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stations Nos 2 and 3 are less than 50 of the 1 21 mV m limitation under the above provision they are nevertheless included for comparative studies and the RSS limitation is calculated to be 1 47 mV m However if the increase proposed by Station No 1 is authorized the RSS value then calculated is 1 21 mV m because Stations Nos 2 and 3 are excluded in view of the fact that the limitations they impose are less than 50 of 1 21 mV m Note The principles demonstrated in the previous examples for the calculation of the 50 exclusion method also apply to calculations using the 25 exclusion method after appropriate adjustment l Objectionable nighttime interference from a station shall be considered to exist to a station when at the field strength contour specified in paragraph q of this section with respect to the class to which the station belongs the field strength of an interfering station operating on the same channel or on a first adjacent channel after signal adjustment using the proper protection ratio exceeds for 10 or more of the time the value of the permissible interfering signal set forth opposite such class in paragraph q of this section m For the purpose of estimating the coverage and the interfering effects of stations in the absence of field strength measurements use shall be made of Figure 8 of 73 190 which describes the estimated effective field for 1 kW power input of simple vertical omnidirectional antennas of various heights with ground systems having at least 120 quarter wavelength radials Certain approximations based on the curve or other appropriate theory may be made when other than such antennas and ground systems are employed but in any event the effective field to be employed shall not | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
be less than the following Effective Class of station field at 1 km All Class A except Alaskan 275 mV m Class A Alaskan B and D 215 mV m Class C 180 mV m Note 1 When a directional antenna is employed the radiated signal of a broadcasting station will vary in strength in different directions possibly being greater than the above values in certain directions and less in other directions depending upon the design and adjustment of the directional antenna system To determine the interference in any direction the measured or calculated radiated field unattenuated field strength at 1 kilometer from the array must be used in conjunction with the appropriate propagation curves See 73 185 for further discussion and solution of a typical directional antenna case Note 2 For Class B stations in Alaska Hawaii Puerto Rico and the U S Virgin Islands 180 mV m shall be used 47 CFR 73 182 m enhanced display page 70 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 182 n Radio Broadcast Services n The existence or absence of objectionable groundwave interference from stations on the same or adjacent channels shall be determined by actual measurements made in accordance with the method described in 73 186 or in the absence of such measurements by reference to the propagation curves of 73 184 The existence or absence of objectionable interference due to skywave propagation shall be determined by reference to Formula 2 in 73 190 o Computation of skywave field strength values 1 Fifty percent skywave field strength values clear channel In computing the fifty percent skywave field strength values of a Class A clear channel station use shall be made of Formula 1 of 73 190 entitled Skywave Field Strength | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
for 50 percent of the time 2 Ten percent skywave field strength values In computing the 10 skywave field strength for stations on a single signal or an RSS basis Formula 2 in 73 190 shall be used 3 Determination of angles of departure In calculating skywave field strength for stations on all channels the pertinent vertical angle shall be determined by use of the formula in 73 190 d p The distance to any specified groundwave field strength contour for any frequency may be determined from the appropriate curves in 73 184 entitled Ground Wave Field Strength vs Distance q Normally protected service contours and permissible interference signals for broadcast stations are as follows for Class A stations see also paragraph a of this section Signal strength contour of area protected from Permissible interfering Class of Class of channel objectionable interference remove footnote signal reference station used µV m µV m Day1 Night Day1 Night2 A Clear SC 100 SC 500 50 SW SC 5 SC 25 AC 500 AC 500 GW AC 250 AC 250 A Alaskan do SC 100 SC 100 50 SW SC 5 SC 5 AC 500 AC 500 GW AC 250 AC 250 B Clear 500 20001 25 25 Regional AC 250 250 C Local 500 No presc 3 SC 25 Not presc D Clear 500 Not presc SC 25 Not presc Regional AC 250 1 Groundwave 2 Skywave field strength for 10 percent or more of the time 3During nighttime hours Class C stations in the contiguous 48 States may treat all Class B stations assigned to 1230 1240 1340 1400 1450 and 1490 kHz in Alaska Hawaii Puerto Rico and the U S Virgin Islands as if they were Class C stations 47 CFR 73 182 q enhanced display page 71 of | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 182 r Radio Broadcast Services Note SC Same channel AC Adjacent channel SW Skywave GW Groundwave r The following table of logarithmic expressions is to be used as required for determining the minimum permissible ratio of the field strength of a desired to an undesired signal This table shall be used in conjunction with the protected contours specified in paragraph q of this section Desired Groundwave to Frequency separation of desired to Undesired Desired 50 Skywave to Undesired 10 undesired signals kHz groundwave Undesired 10 Skywave dB Skywave dB dB 0 26 26 26 10 6 6 not presc s Two stations one with a frequency twice of the other should not be assigned in the same groundwave service area unless special precautions are taken to avoid interference from the second harmonic of the station operating on the lower frequency Additionally in selecting a frequency consideration should be given to the fact that occasionally the frequency assignment of two stations in the same area may bear such a relation to the intermediate frequency of some broadcast receivers as to cause image interference However since this can usually be rectified by readjustment of the intermediate frequency of such receivers the Commission in general will not take this kind of interference into consideration when authorizing stations t The groundwave service of two stations operating with synchronized carriers and broadcasting identical programs will be subject to some distortion in areas where the signals from the two stations are of comparable strength For the purpose of estimating coverage of such stations areas in which the signal ratio is between 1 2 and 2 1 will not be considered as receiving satisfactory service Note Two stations are considered to | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
be operated synchronously when the carriers are maintained within 0 2 Hz of each other and they transmit identical program s 56 FR 64862 Dec 12 1991 57 FR 43290 Sept 18 1992 as amended at 58 FR 27950 May 12 1993 81 FR 2759 Jan 19 2016 73 183 Groundwave signals a Interference that may be caused by a proposed assignment or an existing assignment during daytime hours should be determined when possible by measurements on the frequency involved or on another frequency over the same terrain and by means for the curves in 73 184 entitled Ground Wave Field Strength versus Distance Note Groundwave field strength measurements will not be accepted or considered for the purpose of establishing that interference to a station in a foreign country other than Canada or that the field strength at the border thereof would be less than indicated by the use of the ground conductivity maps and engineering standards contained in this part and applicable international agreements Satisfactory groundwave measurements offered for the purpose of demonstrating 47 CFR 73 183 a enhanced display page 72 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 183 b Radio Broadcast Services values of conductivity other than those shown by Figure M3 in problems involving protection of Canadian stations will be considered only if after review thereof the appropriate agency of the Canadian government notifies the Commission that they are acceptable for such purpose b 1 In all cases where measurements taken in accordance with the requirements are not available the groundwave strength must be determined by means of the pertinent map of ground conductivity and the groundwave curves of field strength versus distance The conductivity of a given terrain may be determined by measurements of any | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
broadcast signal traversing the terrain involved Figure M3 See Note 1 shows the conductivity throughout the United States by general areas of reasonably uniform conductivity When it is clear that only one conductivity value is involved Figure R3 of 73 190 may be used It is a replica of Figure M3 and is contained in these standards In all other situations Figure M3 must be employed It is recognized that in areas of limited size or over a particular path the conductivity may vary widely from the values given therefore these maps are to be used only when accurate and acceptable measurements have not been made 2 For determinations of interference and service requiring a knowledge of ground conductivities in other countries the ground conductivity maps comprising Appendix 1 to Annex 2 of each of the following international agreements may be used i For Canada the U S Canada AM Agreement 1984 ii For Mexico the U S Mexico AM Agreement 1986 and iii For other Western Hemisphere countries the Regional Agreement for the Medium Frequency Broadcasting Service in Region 2 Where different conductivities appear in the maps of two countries on opposite sides of the border such differences are to be considered as real even if they are not explained by geophysical cleavages c Example of determining interference by the graphs in 73 184 It is desired to determine whether objectionable interference exists between a proposed 5 kW Class B station on 990 kHz and an existing 1 kW Class B station on first adjacent channel 1000 kHz The distance between the two stations is 260 kilometers and both stations operate nondirectionally with antenna systems that produce a horizontal effective field of 282 in mV m at one kilometer See 73 185 regarding use of directional antennas The ground | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
conductivity at the site of each station and along the intervening terrain is 6 mS m The protection to Class B stations during daytime is to the 500 µV m 0 5 Vm contour using a 6 dB protection factor The distance to the 500 µV m groundwave contour of the 1 kW station is determined by the use of the appropriate curve in 73 184 Since the curve is plotted for 100 mV m at a 1 kilometer to find the distance of the 0 5 mV m contour of the 1 kw station it is necessary to determine the distance to the 0 1773 m Vm contour 100 0 5 282 0 1773 Using the 6 mS m curve the estimated radius of the 0 5 mV m contour is 62 5 kilometers Subtracting this distance from the distance between the two stations leaves 197 5 kilometers Using the same propagation curve the signal from the 5 kW station at this distance is seen to be 0 059 mV m Since a protection ratio of 6 47 CFR 73 183 c enhanced display page 73 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 183 d Radio Broadcast Services dB desired to undesired signal applies to stations separated by 10 kHz the undesired signal could have had a value of up to 0 25 mV m without causing objectionable interference For co channel studies a desired to undesired signal ratio of no less than 20 1 26 dB is required to avoid causing objectionable interference d Where a signal traverses a path over which different conductivities exist the distance to a particular groundwave field strength contour shall be determined by the use of the equivalent distance method Reasonably accurate results | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
may be expected in determining field strengths at a distance from the antenna by application of the equivalent distance method when the unattenuated field of the antenna the various ground conductivities and the location of discontinuities are known This method considers a wave to be propagated across a given conductivity according to the curve for a homogeneous earth of that conductivity When the wave crosses from a region of one conductivity into a region of a second conductivity the equivalent distance of the receiving point from the transmitter changes abruptly but the field strength does not From a point just inside the second region the transmitter appears to be at that distance where on the curve for a homogeneous earth of the second conductivity the field strength equals the value that occurred just across the boundary in the first region Thus the equivalent distance from the receiving point to the transmitter may be either greater or less than the actual distance An imaginary transmitter is considered to exist at that equivalent distance This technique is not intended to be used as a means of evaluating unattenuated field or ground conductivity by the analysis of measured data The method to be employed for such determinations is set out in 73 186 e Example of the use of the equivalent distance method It is desired to determine the distance to the 0 5 mV m and 0 025 mV m contours of a station on a frequency of 1000 kHz with an inverse distance field of 100 mV m at one kilometer being radiated over a path having a conductivity of 10 mS m for a distance of 20 kilometers 5 mS m for the next 30 kilometers and 15 mS m thereafter Using the appropriate curve in 73 184 Graph 12 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
at a distance of 20 kilometers on the curve for 10 mS m the field strength is found to be 2 84 mV m On the 5mS m curve the equivalent distance to this field strength is 14 92 kilometers which is 5 08 20 14 92 kilometers nearer to the transmitter Continuing on the propagation curve the distance to a field strength of 0 5 mV m is found to be 36 11 kilometers The actual length of the path travelled however is 41 19 36 11 5 08 kilometers Continuing on this propagation curve to the conductivity change at 44 92 50 00 5 08 kilometers the field strength is found to be 0 304 mV m On the 15 mS m propagation curve the equivalent distance to this field strength is 82 94 kilometers which changes the effective path length by 38 02 82 94 44 92 kilometers Continuing on this propagation curve the distance to a field strength of 0 025 mV m is seen to be 224 4 kilometers The actual length of the path travelled however is 191 46 224 4 5 08 38 02 kilometers 28 FR 13574 Dec 14 1963 as amended at 44 FR 36037 June 20 1979 48 FR 9011 Mar 3 1983 50 FR 18822 May 2 1985 50 FR 24522 June 11 1985 51 FR 9965 Mar 24 1986 54 FR 39736 Sept 28 1989 56 FR 64866 Dec 12 1991 57 FR 43290 Sept 18 1992 73 184 Groundwave field strength graphs a Graphs 1 to 20 show for each of 20 frequencies the computed values of groundwave field strength as a function of groundwave conductivity and distance from the source of radiation The groundwave field strength is considered to be that part of the vertical component | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
of the electric field which has not been reflected from the ionosphere nor from the troposphere These 20 families of curves are plotted on log log graph paper and each is to be used for the range of frequencies shown thereon Computations are based on a dielectric constant of the ground referred to air as unity equal to 15 for land and 80 for sea 47 CFR 73 184 a enhanced display page 74 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 184 b Radio Broadcast Services water and for the ground conductivities expressed in mS m given on the curves The curves show the variation of the groundwave field strength with distance to be expected for transmission from a vertical antenna at the surface of a uniformly conducting spherical earth with the groundwave constants shown on the curves The curves are for an antenna power of such efficiency and current distribution that the inverse distance unattenuated field is 100 mV m at 1 kilometer The curves are valid for distances that are large compared to the dimensions of the antenna for other than short vertical antennas b The inverse distance field 100 mV m divided by the distance in kilometers corresponds to the groundwave field intensity to be expected from an antenna with the same radiation efficiency when it is located over a perfectly conducting earth To determine the value of the groundwave field intensity corresponding to a value of inverse distance field other than 100 mV m at 1 kilometer multiply the field strength as given on these graphs by the desired value of inverse distance field at 1 kilometer divided by 100 for example to determine the groundwave field strength for a station with an inverse distance field | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
of 2700 mV m at 1 kilometer simply multiply the values given on the charts by 27 The value of the inverse distance field to be used for a particular antenna depends upon the power input to the antenna the nature of the ground in the neighborhood of the antenna and the geometry of the antenna For methods of calculating the interrelations between these variables and the inverse distance field see The Propagation of Radio Waves Over the Surface of the Earth and in the Upper Atmosphere Part II by Mr K A Norton Proc I R E Vol 25 September 1937 pp 1203 1237 Note The computed values of field strength versus distance used to plot Graphs 1 to 20 are available in tabular form For information on obtaining copies of these tabulations call or write the Consumer Affairs Office Federal Communications Commission Washington DC 20554 202 632 7000 c Provided the value of the dielectric constant is near 15 the ground conductivity curves of Graphs 1 to 20 may be compared with actual field strength measurement data to determine the appropriate values of the ground conductivity and the inverse distance field strength at 1 kilometer This is accomplished by plotting the measured field strengths on transparent log log graph paper similar to that used for Graphs 1 to 20 and superimposing the plotted graph over the Graph corresponding to the frequency of the station measured The plotted graph is then shifted vertically until the plotted measurement data is best aligned with one of the conductivity curves on the Graph the intersection of the inverse distance line on the Graph with the 1 kilometer abscissa on the plotted graph determines the inverse distance field strength at 1 kilometer For other values of dielectric constant the following procedure may be | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
used to determine the dielectric constant of the ground the ground conductivity and the inverse distance field strength at 1 kilometer Graph 21 gives the relative values of groundwave field strength over a plane earth as a function of the numerical distance p and phase angle b On graph paper with coordinates similar to those of Graph 21 plot the measured values of field strength as ordinates versus the corresponding distances from the antenna in kilometers as abscissae The data should be plotted only for distances greater than one wavelength or when this is greater five times the vertical height of the antenna in the case of a nondirectional antenna or 10 times the spacing between the elements of a directional antenna and for distances less than 80f1 3 MHz kilometers i e 80 kilometers at 1 MHz Then using a light box place the plotted graph over Graph 21 and shift the plotted graph vertically and horizontally making sure that the vertical lines on both sheets are parallel until the best fit with the data is obtained with one of the curves on Graph 21 When the two sheets are properly lined up the value of the field strength corresponding to the intersection of the inverse distance line of Graph 21 with the 1 kilometer abscissa on the data sheet is 47 CFR 73 184 c enhanced display page 75 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 184 d Radio Broadcast Services the inverse distance field strength at 1 kilometer and the values of the numerical distance at 1 kilometer p1 and of b are also determined Knowing the values of b and p1 the numerical distance at one kilometer we may substitute in the following approximate values of | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
the ground conductivity and dielectric constant R λ 1 Number of wavelengths in 1 kilometer fMHz frequency expressed in megahertz ε dielectric constant on the ground referred to air as unity First solve for χ by substituting the known values of p1 R λ 1 and cos b in equation 1 Equation 2 may then be solved for δ and equation 3 for ε At distances greater than 80 f1 3 MHz kilometers the curves of Graph 21 do not give the correct relative values of field strength since the curvature of the earth weakens the field more rapidly than these plane earth curves would indicate Thus no attempt should be made to fit experimental data to these curves at the larger distances Note For other values of dielectric constant use can be made of the computer program which was employed by the FCC in generating the curves in Graphs 1 to 20 For information on obtaining a printout of this program call or write the Consumer Affairs Office Federal Communications Commission Washington DC 200554 202 632 7000 d At sufficiently short distances less than 55 kilometers at AM broadcast frequencies such that the curvature of the earth does not introduce an additional attenuation of the waves the curves of Graph 21 may be used to determine the groundwave field strength of transmitting and receiving antennas at the surface of the earth for any radiated power frequency or set of ground constants First trace the straight inverse distance line corresponding to the power radiated on transparent log log graph paper similar to that of Graph 21 labelling the ordinates of the chart in terms of field strength and the abscissae in terms of distance Next using the formulas given on Graph 21 calculate the value of the numerical distance p | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
at 1 kilometer and the value of b Then superimpose the log log graph paper over Graph 21 shifting it vertically until both inverse distance lines coincide and shifting it horizontally until the numerical distance at 1 kilometer on Graph 21 coincides with 1 kilometer on the log log graph paper The curve of Graph 21 corresponding to the calculated value of b is then traced on the log log graph paper giving the field strength versus distance in kilometers e This paragraph consists of the following Graphs 1 to 20 and 21 Note The referenced graphs are not published in the CFR nor will they be included in the Commission s automated rules system For information on obtaining copies of the graphs call or write the Consumer Affairs Office Federal Communications Commission Washington DC 20554 Telephone 202 632 7000 47 CFR 73 184 e enhanced display page 76 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 185 Radio Broadcast Services 28 FR 13574 Dec 14 1963 as amended at 50 FR 18823 May 2 1985 51 FR 45891 Dec 23 1986 52 FR 36878 Oct 1 1987 56 FR 64866 Dec 12 1991 57 FR 43290 Sept 18 1992 73 185 Computation of interfering signal a Measured values of radiation are not to be used in calculating overlap interference and coverage 1 In the case of an antenna which is intended to be non directional in the horizontal plane an ideal non directional radiation pattern shall be used in determining interference overlap and coverage even if the antenna is not actually non directional 2 In the case of an antenna which is directional in the horizontal plane the radiation which shall be used in determining interference overlap and coverage is | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
that calculated pursuant to 73 150 or 73 152 depending on whether the station has a standard or modified standard pattern 3 In the case of calculation of interference or overlap to not from a foreign station the notified radiation shall be used even if the notified radiation differs from that in paragraphs a 1 or 2 of this section b For skywave signals from stations operating on all channels interference shall be determined from the appropriate formulas and Figure 6a contained in 73 190 c The formulas in 73 190 d depicted in Figure 6a of 73 190 entitled Angles of Departure versus Transmission Range are to be used in determining the angles in the vertical pattern of the antenna of an interfering station to be considered as pertinent to transmission by one reflection To provide for variation in the pertinent vertical angle due to variations of ionosphere height and ionosphere scattering the curves 2 and 3 indicate the upper and lower angles within which the radiated field is to be considered The maximum value of field strength occurring between these angles shall be used to determine the multiplying factor to apply to the 10 percent skywave field intensity value determined from Formula 2 in 73 190 The multiplying factor is found by dividing the maximum radiation between the pertinent angles by 100 mV m d Example of the use of skywave curves and formulas Assume a proposed new Class B station from which interference may be expected is located at a distance of 724 kilometers from a licensed Class B station The proposed station specifies geographic coordinates of 40 00 00 N and 100 00 00 W and the station to be protected is located at an azimuth of 45 true at geographic coordinates of 44 26 05 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
N and 93 32 54 W The critical angles of radiation as determined from Figure 6a of 73 190 for use with Class B stations are 9 6 and 16 6 If the vertical pattern of the antenna of the proposed station in the direction of the existing station is such that between the angles of 9 6 and 16 6 above the horizon the maximum radiation is 260 mV m at one kilometer the value of the 50 field as derived from Formula 1 of 73 190 is 0 06217 mV m at the location of the existing station To obtain the value of the 10 field the 50 value must be adjusted by a factor derived from Formula 2 of 73 190 The value in this case is 8 42 dB Thus the 10 field is 0 1616 mV m Using this in conjunction with the co channel protection ratio of 26 dB the resultant nighttime limit from the proposed station to the licensed station is 3 232 mV m e In the case of an antenna which is non directional in the horizontal plane the vertical distribution of the relative fields should be computed pursuant to 73 160 In the case of an antenna which is directional in the horizontal plane the vertical pattern in the great circle direction toward the point of reception in question must first be calculated In cases where the radiation in the vertical plane at the pertinent 47 CFR 73 185 e enhanced display page 77 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 185 f Radio Broadcast Services azimuth contains a large lobe at a higher angle than the pertinent angle for one reflection the method of calculating interference will not be | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
restricted to that just described each such case will be considered on the basis of the best knowledge available f In performing calculations to determine permissible radiation from stations operating presunrise or postsunset in accordance with 73 99 calculated diurnal factors will be multiplied by the values of skywave field strength for such stations obtained from Formula 1 or 2 of 73 190 1 The diurnal factor is determined using the time of day at the mid point of path between the site of the interfering station and the point at which interference is being calculated Diurnal factors are computed using the formula Df a bF cF2 dF3 where Df represents the diurnal factor F is the frequency in MHz a b c and d are constants obtained from the tables in paragraph k 2 A diurnal factor greater than one will not be used in calculations and interpolation is to be used between calculated values where necessary For reference purposes curves for presunrise and postsunset diurnal factors are contained in Figures 13 and 14 of 73 190 2 Constants used in calculating diurnal factors for the presunrise and postsunset periods are contained in paragraphs f 2 i and ii of this section respectively The columns labeled Tmp represent the number of hours before and after sunrise and sunset at the path midpoint 47 CFR 73 185 f 2 enhanced display page 78 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 185 f 2 Radio Broadcast Services i Presunrise Constants Tmp a b c d 2 1 3084 0083 0155 0144 1 75 1 3165 4919 6011 1884 1 5 1 0079 0296 1488 0452 1 25 7773 3751 1911 0736 1 6230 1547 2654 1006 75 3718 1178 3632 1172 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
5 2151 0737 4167 1413 25 2027 2560 7269 2577 SR 1504 2325 5374 1729 25 1057 2092 4148 1239 5 0642 1295 2583 0699 75 0446 1002 1754 0405 1 0148 0135 0462 0010 ii Postsunset Constants Tmp a b c d 1 75 9495 0187 0720 0290 1 5 7196 3583 2280 0611 1 25 6756 1518 0279 0163 1 0 5486 1401 0952 0288 75 3003 4050 0961 0256 5 1186 4281 0799 0197 25 0382 3706 0673 0171 SS 0002 3024 0540 0086 25 0278 0458 1473 0486 5 0203 0132 1166 0340 75 0152 0002 0786 0185 1 0 0043 0452 0040 0103 1 25 0010 0135 0103 0047 1 5 0018 0052 0069 0042 1 75 0012 0122 0076 0076 2 0 0024 0141 0141 0091 Editorial Note At 56 FR 64867 Dec 12 1991 73 185 was amended by redesignating paragraphs d e h and k as c d e and f resulting in two consecutive paragraph f s These paragraphs will be correctly designated by a Federal Communication Commission document published in the FEDERAL REGISTER at a later date 47 CFR 73 185 f 2 enhanced display page 79 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 185 f Radio Broadcast Services f For stations operating on regional and local channels interfering skywave field intensities shall be determined in accordance with the procedure specified in d of this section and illustrated in e of this section except that Figure 2 of 73 190 is used in place of Figure 1a and 1b and the formulas of 73 190 In using Figure 2 of 73 190 one additional parameter must be considered i e the variation of received field with the latitude of the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
path g Figure 2 of 73 190 10 percent Skywave Signal Range Chart shows the signal as a function of the latitude of the transmission path which is defined as the geographic latitude of the midpoint between the transmitter and receiver When using Figure 2 of 73 190 latitude 35 should be used in case the mid point of the path lies below 35 North and latitude 50 should be used in case the mid point of the path lies above 50 North 30 FR 13783 Oct 29 1965 as amended at 33 FR 15420 Oct 17 1968 46 FR 11995 Feb 12 1981 48 FR 42958 Sept 20 1983 50 FR 18843 May 2 1985 56 FR 64867 Dec 12 1991 73 186 Establishment of effective field at one kilometer a Section 73 189 provides that certain minimum field strengths are acceptable in lieu of the required minimum physical heights of the antennas proper Also in other situations it may be necessary to determine the effective field The following requirements shall govern the taking and submission of data on the field strength produced 1 Beginning as near to the antenna as possible without including the induction field and to provide for the fact that a broadcast antenna is not a point source of radiation not less than one wave length or 5 times the vertical height in the case of a single element i e nondirectional antenna or 10 times the spacing between the elements of a directional antenna measurements shall be made on six or more radials at intervals of approximately 0 2 kilometer up to 3 kilometers from the antenna at intervals of approximately one kilometer from 3 kilometers to 5 kilometers from the antenna at intervals of approximately 2 kilometers from 5 kilometers to 15 kilometers | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
from the antenna and a few additional measurements if needed at greater distances from the antenna Where the antenna is rurally located and unobstructed measurements can be made there shall be at least 15 measurements on each radial These shall include at least 7 measurements within 3 kilometers of the antenna However where the antenna is located in a city where unobstructed measurements are difficult to make measurements shall be made on each radial at as many unobstructed locations as possible even though the intervals are considerably less than stated above particularly within 3 kilometers of the antenna In cases where it is not possible to obtain accurate measurements at the closer distances even out to 8 or 10 kilometers due to the character of the intervening terrain the measurements at greater distances should be made at closer intervals 2 The data required by paragraph a 1 of this section should be plotted for each radial in accordance with either of the two methods set forth below i Using log log coordinate paper plot field strengths as ordinate and distance as abscissa ii Using semi log coordinate paper plot field strength times distance as ordinate on the log scale and distance as abscissa on the linear scale 3 However regardless of which of the methods in paragraph a 2 of this section is employed the proper curve to be drawn through the points plotted shall be determined by comparison with the curves in 73 184 as follows Place the sheet on which the actual points have been plotted over the appropriate Graph in 73 184 hold to the light if necessary and adjust until the curve most closely 47 CFR 73 186 a 3 enhanced display page 80 of 580 47 CFR Part 73 up to date as of 2 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
20 2024 47 CFR 73 186 a 4 Radio Broadcast Services matching the points is found This curve should then be drawn on the sheet on which the points were plotted together with the inverse distance curve corresponding to that curve The field at 1 kilometer for the radial concerned shall be the ordinate on the inverse distance curve at 1 kilometer 4 When all radials have been analyzed in accordance with paragraph a 3 of this section a curve shall be plotted on polar coordinate paper from the fields obtained which gives the inverse distance field pattern at 1 kilometer The radius of a circle the area of which is equal to the area bounded by this pattern is the effective field See 73 14 5 The antenna power of the station shall be maintained at the authorized level during all field measurements The power determination will be made using the direct method as described in 73 51 a with instruments of acceptable accuracy specified in 73 1215 b Complete data taken in conjunction with the field strength measurements shall be submitted to the Commission in affidavit form including the following 1 Tabulation by number of each point of measurement to agree with the maps required in paragraph c of this section the date and time of each measurement the field strength E the distance from the antenna D and the product of the field strength and distance ED if data for each radial are plotted on semilogarithmic paper see paragraph a 2 ii of this section for each point of measurement 2 Description of method used to take field strength measurements 3 The family of theoretical curves used in determining the curve for each radial properly identified by conductivity and dielectric constants 4 The curves drawn for each | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
radial and the field strength pattern 5 The antenna resistance at the operating frequency 6 Antenna current or currents maintained during field strength measurements c Maps showing each measurement point numbered to agree with the required tabulation shall be retained in the station records and shall be available to the FCC upon request 28 FR 13574 Dec 14 1963 as amended at 41 FR 44178 Oct 7 1976 46 FR 11995 Feb 12 1981 49 FR 49851 Dec 24 1984 50 FR 18843 May 2 1985 50 FR 47055 Nov 14 1985 51 FR 2707 Jan 21 1986 52 FR 10570 Apr 2 1987 66 FR 20757 Apr 25 2001 73 187 Limitation on daytime radiation a 1 Except as otherwise provided in paragraphs a 2 and 3 of this section no authorization will be granted for a Class B or Class D station on a frequency specified in 73 25 if the proposed operation would radiate during the period of critical hours the two hours after local sunrise and the two hours before local sunset toward any point on the 0 1 mV m contour of a co channel U S Class A station at or below the pertinent vertical angle determined from Curve 2 of Figure 6a of 73 190 values in excess of those obtained as provided in paragraph b of this section 2 The limitation set forth in paragraph a 1 of this section shall not apply in the following cases i Any Class B or Class D operation authorized before November 30 1959 or 47 CFR 73 187 a 2 i enhanced display page 81 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 187 a 2 ii Radio Broadcast Services ii For Class B and Class | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
D stations authorized before November 30 1959 subsequent changes of facilities which do not involve a change in frequency an increase in radiation toward any point on the 0 1 mV m contour of a co channel U S Class A station or the move of transmitter site materially closer to the 0 1 mV m contour of such Class A station 3 A Class B or Class D station authorized before November 30 1959 and subsequently authorized to increase daytime radiation in any direction toward the 0 1 mV m contour of a co channel U S Class A station without a change in frequency or a move of transmitter site materially closer to such contour may not during the two hours after local sunrise or the two hours before local sunset radiate in such directions a value exceeding the higher of i The value radiated in such directions with facilities last authorized before November 30 1959 or ii The limitation specified in paragraph a 1 of this section b To obtain the maximum permissible radiation for a Class B or Class D station on a given frequency from 640 through 990 kHz multiply the radiation value obtained for the given distance and azimuth from the 500 kHz chart Figure 9 of 73 190 by the appropriate interpolation factor shown in the K500 column of paragraph c of this section and multiply the radiation value obtained for the given distance and azimuth from the 1000 kHz chart Figure 10 of 73 190 by the appropriate interpolation factor shown in the K1000 column of paragraph c of this section Add the two products thus obtained the result is the maximum radiation value applicable to the Class B or Class D station in the pertinent directions For frequencies from 1010 to | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
1580 kHz obtain in a similar manner the proper radiation values from the 1000 and 1600 kHz charts Figures 10 and 11 of 73 190 multiply each of these values by the appropriate interpolation factors in the K 1000 and K 1600 columns in paragraph c of this section and add the products c Interpolation factors 1 Frequencies below 1000 kHz fkHz K500 K1000 640 0 720 0 280 650 0 700 0 300 660 0 680 0 320 670 0 660 0 340 680 0 640 0 360 690 0 620 0 380 700 0 600 0 400 710 0 580 0 420 720 0 560 0 440 730 0 540 0 460 740 0 520 0 480 750 0 500 0 500 760 0 480 0 520 770 0 460 0 540 780 0 440 0 560 800 0 400 0 600 47 CFR 73 187 c 1 enhanced display page 82 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 187 c 2 Radio Broadcast Services fkHz K500 K1000 810 0 380 0 620 820 0 360 0 640 830 0 340 0 660 840 0 320 0 680 850 0 300 0 700 860 0 280 0 720 870 0 260 0 740 880 0 240 0 760 890 0 220 0 780 900 0 200 0 800 940 0 120 0 880 990 0 020 0 980 2 Frequencies above 1000 kHz f kHz K 1000 K 1600 1010 0 983 0 017 1020 0 967 0 033 1030 0 950 0 050 1040 0 933 0 067 1050 0 917 0 083 1060 0 900 0 100 1070 0 883 0 117 1080 0 867 0 133 1090 0 850 0 150 1100 0 833 0 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
167 1110 0 817 0 183 1120 0 800 0 200 1130 0 783 0 217 1140 0 767 0 233 1160 0 733 0 267 1170 0 717 0 283 1180 0 700 0 300 1190 0 683 0 317 1200 0 667 0 333 1210 0 650 0 350 1220 0 633 0 367 1500 0 167 0 833 1510 0 150 0 850 1520 0 133 0 867 47 CFR 73 187 c 2 enhanced display page 83 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 189 Radio Broadcast Services f kHz K 1000 K 1600 1530 0 117 0 883 1540 0 100 0 900 1550 0 083 0 917 1560 0 067 0 933 1570 0 050 0 950 1580 0 033 0 967 28 FR 13574 Dec 14 1963 as amended at 49 FR 43962 Nov 1 1984 56 FR 64868 Dec 12 1991 73 189 Minimum antenna heights or field strength requirements a Section 73 45 requires that all applicants for new additional or different broadcast facilities and all licensees requesting authority to move 0the transmitter of an existing station shall specify a radiating system the efficiency of which complies with the requirements of good engineering practice for the class and power of the station b The specifications deemed necessary to meet the requirements of good engineering practice at the present state of the art are set out in detail below 1 The licensee of a AM broadcast station requesting a change in power time of operation frequency or transmitter location must also request authority to install a new antenna system or to make changes in the existing antenna system which will meet the minimum height requirements or submit evidence that the present antenna | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
system meets the minimum requirements with respect to field strength before favorable consideration will be given thereto See 73 186 In the event it is proposed to make substantial changes in an existing antenna system the changes shall be such as to meet the minimum height requirements or will be permitted subject to the submission of field strength measurements showing that it meets the minimum requirements with respect to effective field strength 2 These minimum actual physical vertical heights of antennas permitted to be installed are shown by curves A B and C of Figure 7 of 73 190 as follows i Class C stations and stations in Alaska Hawaii Puerto Rico and the U S Virgin Islands on 1230 1240 1340 1400 1450 and 1490 kHz that were formerly Class C and were redesignated as Class B pursuant to 73 26 b 45 meters or a minimum effective field strength of 180 mV m for 1 kW at 1 kilometer 90 mV m for 0 25 kW at 1 kilometer This height applies to a Class C station on a local channel only Curve A shall apply to any Class C stations in the 48 conterminous States that are assigned to Regional channels ii Class A Alaska Class B and Class D stations other than those covered in 73 189 b 2 i a minimum effective field strength of 215 mV m for 1 kW at 1 kilometer iii Class A stations a minimum effective field strength of 275 mV m for 1 kW at 1 kilometer 3 The heights given on the graph for the antenna apply regardless of whether the antenna is located on the ground or on a building Except for the reduction of shadows locating the antenna on a building does not necessarily increase the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
efficiency and where the height of the building is in the order of a quarter wave the efficiency may be materially reduced 47 CFR 73 189 b 3 enhanced display page 84 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 189 b 4 Radio Broadcast Services 4 At the present development of the art it is considered that where a vertical radiator is employed with its base on the ground the ground system should consist of buried radial wires at least one fourth wave length long There should be as many of these radials evenly spaced as practicable and in no event less than 90 120 radials of 0 35 to 0 4 of a wave length in length and spaced 3 is considered an excellent ground system and in case of high base voltage a base screen of suitable dimensions should be employed 5 In case it is contended that the required antenna efficiency can be obtained with an antenna of height or ground system less than the minimum specified a complete field strength survey must be supplied to the Commission showing that the field strength at a mile without absorption fulfills the minimum requirements See 73 186 This field survey must be made by a qualified engineer using equipment of acceptable accuracy 6 The main element or elements of a directional antenna system shall meet the above minimum requirements with respect to height or effective field strength No directional antenna system will be approved which is so designed that the effective field of the array is less than the minimum prescribed for the class of station concerned or in case of a Class A station less than 90 percent of the ground wave field which would be obtained from | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
a perfect antenna of the height specified by Figure 7 of 73 190 for operation on frequencies below 1000 kHz and in the case of a Class B or Class D station less than 90 percent of the ground wave field which would be obtained from a perfect antenna of the height specified by Figure 7 of 73 190 for operation on frequencies below 750 kHz 28 FR 13574 Dec 14 1963 as amended at 31 FR 8069 June 8 1966 33 FR 15420 Oct 17 1968 44 FR 36038 June 20 1979 50 FR 18844 May 2 1985 51 FR 2707 Jan 21 1986 51 FR 4753 Feb 7 1986 52 FR 10570 Apr 2 1987 56 FR 64868 Dec 12 1991 81 FR 2760 Jan 19 2016 73 190 Engineering charts and related formulas a This section consists of the following Figures 2 r3 5 6a 7 8 9 10 11 12 and 13 Additionally formulas that are directly related to graphs are included b Formula 1 is used for calculation of 50 skywave field strength values Formula 1 Skywave field strength 50 of the time at SS 6 The skywave field strength Fc 50 for a characteristic field strength of 100 mV m at 1 km is given by The slant distance D is given by The geomagnetic latitude of the midpoint of the path ΦM is given by ΦM arcsin sin aM sin 78 5 cos aM cos 78 5 cos 69 bM degrees Eq 3 47 CFR 73 190 b enhanced display page 85 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 c Radio Broadcast Services The short great circle path distance d is given by Where d arccos sin aT sin aR cos aT | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
cos aR cos bR bT degrees Eq 5 Where aT is the geographic latitude of the transmitting terminal degrees aR is the geographic latitude of the receiving terminal degrees bT is the geographic longitude of the transmitting terminal degrees bR is the geographic longitude of the receiving terminal degrees aM is the geographic latitude of the midpoint of the great circle path degrees and is given by bM is the geographic longitude of the midpoint of the great circle path degrees and is given by Note 1 If FM is greater than 60 degrees equation 1 is evaluated for FM 60 degrees Note 2 North and east are considered positive south and west negative Note 3 In equation 7 k 1 for west to east paths i e bR bT otherwise k 1 c Formula 2 is used for calculation of 10 skywave field strength values Formula 2 Skywave field strength 10 of the time at SS 6 The skywave field strength Fc 10 is given by Fc 10 Fc 50 Δ dB µV m 47 CFR 73 190 c enhanced display page 86 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 d Radio Broadcast Services Where Δ 6 when FM 40 Δ 0 2 FM 2 when 40 FM 60 Δ 10 when FM 60 d Figure 6a depicts angles of departure versus transmission range These angles may also be computed using the following formulas Where d distance in kilometers n 1 for 50 field strength values n 2 or 3 for 10 field strength values and where K1 0 00752 K2 0 00938 K3 0 00565 Note Computations using these formulas should not be carried beyond 0 1 degree e In the event of disagreement between computed values | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
using the formulas shown above and values obtained directly from the figures the computed values will control 47 CFR 73 190 e enhanced display page 87 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 88 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 89 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 90 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 91 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 92 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 93 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 94 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 95 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
e enhanced display page 96 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 97 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 98 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 99 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 190 e Radio Broadcast Services 47 CFR 73 190 e enhanced display page 100 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 201 Radio Broadcast Services 28 FR 13574 Dec 14 1963 as amended at 30 FR 12720 Oct 6 1965 33 FR 15420 Oct 17 1968 48 FR 42959 Sept 20 1983 49 FR 43963 Nov 1 1984 50 FR 18844 May 2 1985 51 FR 4753 Feb 7 1986 52 FR 36879 Oct 1 1987 56 FR 64869 Dec 12 1991 Subpart B FM Broadcast Stations 73 201 Numerical designation of FM broadcast channels The FM broadcast band consists of that portion of the radio frequency spectrum between 88 MHz and 108 MHz It is divided into 100 channels of 200 kHz each For convenience the frequencies available for FM broadcasting including those assigned to noncommercial educational broadcasting are given numerical designations which are shown in the table below Frequency Mc s Channel No 88 1 201 88 3 202 88 5 203 88 7 204 88 9 205 89 1 206 89 3 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
207 89 5 208 89 7 209 89 9 210 90 1 211 90 3 212 90 5 213 90 7 214 90 9 215 91 1 216 91 3 217 91 5 218 91 7 219 91 9 220 92 1 221 92 3 222 92 5 223 92 7 224 92 9 225 93 1 226 93 3 227 93 5 228 93 7 229 93 9 230 47 CFR 73 201 enhanced display page 101 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 201 Radio Broadcast Services Frequency Mc s Channel No 94 1 231 94 3 232 94 5 233 94 7 234 94 9 235 95 1 236 95 3 237 95 5 238 95 7 239 95 9 240 96 1 241 96 3 242 96 5 243 96 7 244 96 9 245 97 1 246 97 3 247 97 5 248 97 7 249 97 9 250 98 1 251 98 3 252 98 5 253 98 7 254 98 9 255 99 1 256 99 3 257 99 5 258 99 7 259 99 9 260 100 1 261 100 3 262 100 5 263 100 7 264 100 9 265 101 1 266 101 3 267 101 5 268 101 7 269 101 9 270 47 CFR 73 201 enhanced display page 102 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 Radio Broadcast Services Frequency Mc s Channel No 102 1 271 102 3 272 102 5 273 102 7 274 102 9 275 103 1 276 103 3 277 103 5 278 103 7 279 103 9 280 104 1 281 104 3 282 104 5 283 104 7 284 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
104 9 285 105 1 286 105 3 287 105 5 288 105 7 289 105 9 290 106 1 291 106 3 292 106 5 293 106 7 294 106 9 295 107 1 296 107 3 297 107 5 298 107 7 299 107 9 300 NOTE The frequency 108 0 MHz may be assigned to VOR test stations subject to the condition that interference is not caused to the reception of FM broadcasting stations present or future 28 FR 13623 Dec 14 1963 as amended at 30 FR 4480 Apr 7 1965 52 FR 10570 Apr 2 1987 73 202 Table of Allotments a General The following Table of Allotments contains the channels other than noncommercial educational Channels 201 220 designated for use in communities in the United States its territories and possessions and not currently assigned to a licensee or permittee or subject to a pending application for construction permit or license All listed channels are for Class B stations in Zones I and I A and for Class 47 CFR 73 202 a enhanced display page 103 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 a 1 Radio Broadcast Services C stations in Zone II unless otherwise specifically designated Channels to which licensed permitted and reserved facilities have been assigned are reflected in the Media Bureau s publicly available Consolidated Data Base System 1 Channels designated with an asterisk may be used only by noncommercial educational broadcast stations The rules governing the use of those channels are contained in part 73 subpart C of this chapter An entity that would be eligible to operate a noncommercial educational broadcast station can in conjunction with an initial petition for rulemaking filed pursuant to part 1 subpart C | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
of this chapter request that a nonreserved FM channel channels 221 through 300 be allotted as reserved only for noncommercial educational broadcasting by demonstrating the following i No reserved channel can be used without causing prohibited interference to TV channel 6 stations or foreign broadcast stations or ii The applicant is technically precluded from using the reserved band by existing stations or previously filed applications and the proposed station would provide a first or second noncommercial educational radio service to 2 000 or more people who constitute 10 of the population within the proposed allocation s 60 dBu 1 mV m service contour 2 Each channel listed in the Table of Allotments reflects the class of station that is authorized to use it based on the minimum and maximum facility requirements for each class contained in 73 211 Note The provisions of this paragraph a 2 of this section become effective 3 years from the effective date of the Report and Order in BC Docket 80 90 b Table of FM Allotments Table 1 to Paragraph b U S States Channel No ALABAMA Camden 230A Hamilton 221A Maplesville 292A Thomaston 280C3 ALASKA Kotzebue 280A Yakutat 280A ARIZONA Aguila 297C2 Ajo 275A Desert Hills 292A Ehrenberg 228C2 First Mesa 281C 47 CFR 73 202 b enhanced display page 104 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Fredonia 266C1 Leupp 293C1 Overgaard 234C1 Parker 257C2 Paulden 228C3 Peach Springs 287A Pima 296A Salome 231A Sells 285A Snowflake 259C2 Tusayan 222C1 Wickenburg 229C3 ARKANSAS Hermitage 300A Lake Village 278C3 Rison 255A Strong 296C3 CALIFORNIA Alturas 277C Avenal 269A Boonville 300A Cartago 233A Cedarville 238A Coalinga 247B1 Coalinga 261B Cottonwood 221A Dos Palos 240A Earlimart 228A Essex | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
280B Firebaugh 234A Ford City 271A Ft Bragg 253B1 Kettleman City 299A Lindsay 277B1 Ludlow 261B1 Portola 258A Randsburg 275A Sacramento 300B Tecopa 256A Visalia 241A 47 CFR 73 202 b enhanced display page 105 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Wasco 224A COLORADO Battlement Mesa 275C3 Calhan 284C3 Dinosaur 262C1 Dotsero 261A Eckley 257C1 Hugo 222A Idalia 231A Lake City 247A Olathe 270C2 293C Stratton 246C1 Walden 226A Yampa 277C3 CONNECTICUT DELAWARE DISTRICT OF COLUMBIA FLORIDA Big Coppitt Key 265C3 Cross City 249C3 Fort Walton Beach 295A Horseshoe Beach 234C3 Otter Creek 240A GEORGIA Pembroke 257C1 Plains 290A HAWAII IDAHO Weiser 247C1 ILLINOIS Abingdon 291A Cedarville 258A Greenup 230A Pinckneyville 282A INDIANA Columbus 228A Fowler 291A Madison 265A IOWA Asbury 254A 47 CFR 73 202 b enhanced display page 106 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Dunkerton 280A Keosauqua 271C3 Moville 246A Rockford 225A Rudd 268A KANSAS Council Grove 281C3 KENTUCKY Irvington 261A LOUISIANA Florien 222A Golden Meadow 289C2 Haynesville 286A Hornbeck 269A Oil City 285A Wisner 300C3 MAINE MARYLAND MASSACHUSETTS Orange 247A West Tisbury 282A MICHIGAN Bear Lake 264C3 Carney 260A Custer 260A Houghton 242C1 Lake Isabella 255A Lexington 256A Onekama 227C3 Pigeon 267A MINNESOTA Grand Marais 245C3 Grand Portage 251A MISSISSIPPI Bruce 233A Cleveland 226C2 Greenwood 230C3 McLain 245A New Albany 268A New Augusta 269A 47 CFR 73 202 b enhanced display page 107 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No MISSOURI Bourbon 231A Bunker 292C3 Cuba 269A Eminence 281A Maryville 285C3 Wheatland 272A | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
MONTANA Cut Bank 265C2 Valler 289C1 NEBRASKA Bayard 251A NEVADA Caliente 264A Owyhee 247C1 Tonopah 224A NEW HAMPSHIRE Enfield 282A Groveton 268A Jefferson 247A Stratford 254A NEW JERSEY NEW MEXICO Animas 279C1 Carrizozo 261C2 Chama 241C3 Clovis 272C3 Des Moines 287C Lovington 269C3 Skyline Ganipa 240A NEW YORK Keeseville 231A Narrowsburg 275A Sagaponack 233A Shelter Island 277A Westfield 265A NORTH CAROLINA NORTH DAKOTA Beulah 250A Gackle 256C1 47 CFR 73 202 b enhanced display page 108 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Medina 222C1 Sarles 290C1 OHIO Dennison 272A OKLAHOMA Arnett 293C2 Cheyenne 247C2 Clayton 262A Coalgate 242A Cordell 229A Covington 290A Savanna 275A Vici 249A Wayne 266A Weatherford 286A Wright City 295A OREGON Arlington 295C2 Diamond Lake 251A Huntington 228C1 Vale 288C PENNSYLVANIA Liberty 298A RHODE ISLAND SOUTH CAROLINA Edgefield 238A SOUTH DAKOTA Edgemont 289C1 TENNESSEE Englewood 250A TEXAS Albany 255A Asherton 284A Aspermont 226C2 Balmorhea 283C Benjamin 237C3 Big Lake 246A 252C2 281C1 296C3 Bogata 247A Bruni 293A Canadian 235C1 47 CFR 73 202 b enhanced display page 109 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Carrizo Springs 228A 295A Centerville 274A Crystal Beach 268A Dalhart 261C2 Denver City 248C2 Dickens 240A 294A Dilley 291A Eden 294A El Indio 236A Encino 250A 283A Estelline 263C3 Fort Stockton 263C Freer 288A George West 292A Girard 248C3 Goree 277A Groom 223A 273A Hale Center 236C1 Hamilton 263A Hamlin 283C2 Hereford 278C2 Iraan 269C2 Jayton 231C2 Junction 228C2 277C3 290A Kermit 289C3 Knox City 293A Leakey 275A 299A Lockney 271C3 Lometa 253A Lovelady 288A Marathon 276C1 Marquez 296A Mason 239C2 Matador 244C2 276C3 McCamey 233C3 237C3 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
McLean 298C3 Memphis 292A Menard 265A 292A Milano 274A Mullin 224A 277A 47 CFR 73 202 b enhanced display page 110 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Munday 270C1 O Donnell 249A Olney 282A Palacios 259C1 Pearsall 277A Premont 264C3 287A Richland Springs 235A 299A Rising Star 290C3 Roaring Springs 227A Roby 290A Rocksprings 291A Roscoe 228A Rule 253A San Isidro 255A 278A Sanderson 274C1 Sanger 281C3 Seymour 222C2 Sheffield 224C2 Silverton 221A Sonora 272C3 South Padre Island 288A Teague 237C3 Trinity 251A Turkey 221C2 Van Alstyne 260A Wellington 248C3 253C3 Wells 254A Westbrook 272A Wharton 277C2 Zapata 292A UTAH Huntington 287C3 Milford 288C Paragonah 258A VERMONT Barton 262A Hardwick 290A West Rutland 298A VIRGINIA WASHINGTON 47 CFR 73 202 b enhanced display page 111 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 202 b Radio Broadcast Services Channel No Coupeville 266A Kahlotus 283A Oak Harbor 233A Raymond 300A Trout Lake 236A WEST VIRGINIA WISCONSIN Ashland 275A Crandon 276A Hayward 232C2 Laona 272C3 Lac Du Flambeau 225A New Holstein 258A Tomahawk 265C3 WYOMING Albin 282C3 Bairoil 235C3 Basin 299C1 Cora 274C2 Dubois 242A Jackson 294C2 Lusk 242A Manville 255C1 Marbleton 257C1 Medicine Bow 259C3 Pine Bluffs 287A Ralston 233C Rawlins 298C2 Rozet 256C3 Wamsutter 285A Wheatland 286A 293A U S Territories AMERICAN SAMOA CENTRAL MARIANAS GARAPAN GUAM PUERTO RICO VIRGIN ISLANDS Charlotte Amalie 237B Charlotte Amalie 275A 47 CFR 73 202 b enhanced display page 112 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 203 Radio Broadcast Services 30 FR 12711 Oct 6 1965 Editorial Note For FEDERAL REGISTER citations affecting 73 202 see | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
the List of CFR Sections Affected which appears in the Finding Aids section of the printed volume and at www govinfo gov 73 203 Availability of channels a Except as provided for in paragraph b of this section and 1 401 d of this chapter and 73 3573 a 1 applications may be filed to construct new FM broadcast stations only at the communities and on the channels contained in the Table of Allotments 73 202 b b Applications filed on a first come first served basis for the minor modification of an existing FM broadcast station may propose any change in channel and or class and or community not defined as major in 73 3573 a Applications for a change in community of license must comply with the requirements set forth in 73 3573 g Note to 73 203 This section is limited to non reserved band changes in channel and or class and or community Applications requesting such changes must meet either the minimum spacing requirements of 73 207 at the site specified in the application without resort to the provisions of the Commission s rules permitting short spaced stations as set forth in 73 213 through 73 215 or demonstrate by a separate exhibit attached to the application the existence of a suitable allotment site that fully complies with 73 207 and 73 315 without resort to 73 213 through 73 215 71 FR 76219 Dec 20 2006 73 204 International agreements and other restrictions on use of channels See 73 207 73 220 and 73 1650 49 FR 10264 Mar 20 1984 73 205 Zones For the purpose of allotments and assignments the United States is divided into three zones as follows a Zone I consists of that portion of the United States located within the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
confines of the following lines drawn on the United States Albers Equal Area Projection Map based on standard parallels 291 2 and 451 2 North American datum Beginning at the most easterly point on the State boundary line between North Carolina and Virginia thence in a straight line to a point on the Virginia West Virginia boundary line located at north latitude 37 49 and west longitude 80 12 30 thence westerly along the southern boundary lines of the States of West Virginia Ohio Indiana and Illinois to a point at the junction of the Illinois Kentucky and Missouri State boundary lines thence northerly along the western boundary line of the State of Illinois to a point at the junction of the Illinois Iowa and Wisconsin State boundary lines thence easterly along the northern State boundary line of Illinois to the 90th meridian thence north along this meridian to the 43 5 parallel thence east along this parallel to the United States Canada border thence southerly and following that border until it again intersects the 43 5 parallel thence east along 47 CFR 73 205 a enhanced display page 113 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 205 b Radio Broadcast Services this parallel to the 71st meridian thence in a straight line to the intersection of the 69th meridian and the 45th parallel thence east along the 45th parallel to the Atlantic Ocean When any of the above lines pass through a city the city shall be considered to be located in Zone I See Figure 1 of 73 699 b Zone I A consists of Puerto Rico the Virgin Islands and that portion of the State of California which is located south of the 40th parallel c Zone | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
II consists of Alaska Hawaii and the rest of the United States which is not located in either Zone I or Zone I A 29 FR 14116 Oct 14 1964 and 31 FR 10125 July 27 1966 as amended at 48 FR 29504 June 27 1983 73 207 Minimum distance separation between stations a Except for assignments made pursuant to 73 213 or 73 215 FM allotments and assignments must be separated from other allotments and assignments on the same channel co channel and five pairs of adjacent channels by not less than the minimum distances specified in paragraphs b and c of this section The Commission will not accept petitions to amend the Table of Allotments unless the reference points meet all of the minimum distance separation requirements of this section The Commission will not accept applications for new stations or applications to change the channel or location of existing assignments unless transmitter sites meet the minimum distance separation requirements of this section or such applications conform to the requirements of 73 213 or 73 215 However applications to modify the facilities of stations with short spaced antenna locations authorized pursuant to prior waivers of the distance separation requirements may be accepted provided that such applications propose to maintain or improve that particular spacing deficiency Class D secondary assignments are subject only to the distance separation requirements contained in paragraph b 3 of this section See 73 512 for rules governing the channel and location of Class D secondary assignments b The distances listed in Tables 1 2 and 3 of this paragraph b apply to allotments and assignments on the same channel and each of five pairs of adjacent channels The five pairs of adjacent channels are the first 200 kHz above and 200 kHz below the channel | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
under consideration the second 400 kHz above and below the third 600 kHz above and below the fifty third 10 6 MHz above and below and the fifty fourth 10 8 MHz above and below The distances in the Tables apply regardless of whether the proposed station class appears first or second in the Relation column of the table 1 Domestic distance separation Domestic allotments and assignments must be separated from each other by not less than the distances in Table 1 to this paragraph b Table 1 to Paragraph b Minimum Distance Separation Requirements in Kilometers Miles Relation Co channel 200 kHz 400 600 kHz 10 6 10 8 MHz A to A 115 71 72 45 31 19 10 6 A to B1 143 89 96 60 48 30 12 7 A to B 178 111 113 70 69 43 15 9 A to C3 142 88 89 55 42 26 12 7 47 CFR 73 207 b 1 enhanced display page 114 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 207 b 2 Radio Broadcast Services Relation Co channel 200 kHz 400 600 kHz 10 6 10 8 MHz A to C2 166 103 106 66 55 34 15 9 A to C1 200 124 133 83 75 47 22 14 A to C0 215 134 152 94 86 53 25 16 A to C 226 140 165 103 95 59 29 18 B1 to B1 175 109 114 71 50 31 14 9 B1 to B 211 131 145 90 71 44 17 11 B1 to C3 175 109 114 71 50 31 14 9 B1 to C2 200 124 134 83 56 35 17 11 B1 to C1 233 145 161 100 77 48 24 15 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
B1 to C0 248 154 180 112 87 54 27 17 B1 to C 259 161 193 120 105 65 31 19 B to B 241 150 169 105 74 46 20 12 B to C3 211 131 145 90 71 44 17 11 B to C2 241 150 169 105 74 46 20 12 B to C1 270 168 195 121 79 49 27 17 B to C0 272 169 214 133 89 55 31 19 B to C 274 170 217 135 105 65 35 22 C3 to C3 153 95 99 62 43 27 14 9 C3 to C2 177 110 117 73 56 35 17 11 C3 to C1 211 131 144 90 76 47 24 15 C3 to C0 226 140 163 101 87 54 27 17 C3 to C 237 147 176 109 96 60 31 19 C2 to C2 190 118 130 81 58 36 20 12 C2 to C1 224 139 158 98 79 49 27 17 C2 to C0 239 148 176 109 89 55 31 19 C2 to C 249 155 188 117 105 65 35 22 C1 to C1 245 152 177 110 82 51 34 21 C1 to C0 259 161 196 122 94 58 37 23 C1 to C 270 168 209 130 105 65 41 25 C0 to C0 270 168 207 129 96 60 41 25 C0 to C 281 175 220 137 105 65 45 28 C to C 290 180 241 150 105 65 48 30 2 Canadian border distance separation Under the 1991 United States Canada FM Broadcasting Agreement as amended any domestic U S allotment or assignment within 320 kilometers 199 miles of the common border must either satisfy the contour overlap provisions set out in the Agreement or be separated | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
from Canadian allotments and assignments by not less than the distance given in Table 2 to this paragraph b using the distance calculation methodology set out in the Agreement When applying Table 2 U S Class C0 allotments and assignments are considered to be Class C U S Class C2 allotments and assignments are considered to be Class B and U S Class C3 allotments and assignments are considered to be Class B1 47 CFR 73 207 b 2 enhanced display page 115 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 207 b 3 Radio Broadcast Services Table 2 to Paragraph b Minimum Distance Separation Requirements in Kilometers Canada 10 6 10 8 MHz Relation Co channel 200 kHz 400 kHz 600 kHz I F A1 to A1 78 45 24 20 4 A1 to A 131 78 44 40 7 A1 to B1 164 98 57 53 9 A1 to B 190 117 71 67 12 A1 to C1 223 148 92 88 19 A1 to C 227 162 103 99 26 A to A 151 98 51 42 10 A to B1 184 119 64 55 12 A to B 210 137 78 69 15 A to C1 243 168 99 90 22 A to C 247 182 110 101 29 B1 to B1 197 131 70 57 24 B1 to B 223 149 84 71 24 B1 to C1 256 181 108 92 40 B1 to C 259 195 116 103 40 B to B 237 164 94 74 24 B to C1 271 195 115 95 40 B to C 274 209 125 106 40 C1 to C1 292 217 134 101 48 C1 to C 302 230 144 111 48 C to C 306 241 153 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
113 48 3 Mexican border distance separation Under the 1992 United States Mexico FM Broadcasting Agreement any domestic U S assignment or allotment within 320 kilometers 199 miles of the common border must either satisfy the contour overlap provisions set out in section 7 3 of the Agreement or be separated from Mexican assignments or allotments by not less than the distances given in Table 3 to this paragraph b using the distance calculation methodology set out in the Agreement The minimum required distance separation between I F allotments and assignments cannot be reduced When applying Table 3 i U S or Mexican assignments or allotments which have been notified internationally as Class A are limited to a maximum of 3 0 kW ERP at 100 meters HAAT or the equivalent ii U S or Mexican assignments or allotments which have been notified internationally as Class AA are limited to a maximum of 6 0 kW ERP at 100 meters HAAT or the equivalent iii U S Class C3 assignments or allotments are considered Class B1 47 CFR 73 207 b 3 iii enhanced display page 116 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 207 b 3 iv Radio Broadcast Services iv U S Class C2 assignments or allotments are considered Class B v Class C1 assignments or allotments assume maximum facilities of 100 kW ERP at 300 meters HAAT However U S Class C1 stations may not in any event exceed the domestic U S limit of 100 kW ERP at 299 meters HAAT or the equivalent and vi U S Class C0 assignments or allotments are considered Class C Table 3 to Paragraph b Minimum Distance Separation Requirements in Kilometers Mexico Relation Co Channel 200 kHz 400 kHz | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
or 600 kHz 10 6 or 10 8 MHz I F A to A 100 61 25 8 A to AA 111 68 31 9 A to B1 138 88 48 11 A to B 163 105 65 14 A to C1 196 129 74 21 A to C 210 161 94 28 AA to AA 115 72 31 10 AA to B1 143 96 48 12 AA to B 178 125 69 15 AA to C1 200 133 75 22 AA to C 226 165 95 29 B1 to B1 175 114 50 14 B1 to B 211 145 71 17 B1 to C1 233 161 77 24 B1 to C 259 193 96 31 B to B 237 164 65 20 B to C1 270 195 79 27 B to C 270 215 98 35 C1 to C1 245 177 82 34 C1 to C 270 209 102 41 C to C 290 228 105 48 c The distances listed below apply only to allotments and assignments on Channel 253 98 5 MHz The Commission will not accept petitions to amend the Table of Allotments applications for new stations or applications to change the channel or location of existing assignments where the following minimum distances between transmitter sites in kilometers from any TV Channel 6 allotment or assignment are not met 47 CFR 73 207 c enhanced display page 117 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 208 Radio Broadcast Services Minimum Distance Separation From TV Channel 6 82 88 MHz FM Class TV Zone I TV Zones II III A 17 22 B1 19 23 B 22 26 C3 19 23 C2 22 26 C1 29 33 C 36 41 48 FR 29504 June 27 1983 as | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
amended at 49 FR 10264 Mar 20 1984 49 FR 19670 May 9 1984 49 FR 50047 Dec 26 1984 51 FR 26250 July 22 1986 54 FR 14963 Apr 14 1989 54 FR 16366 Apr 24 1989 54 FR 19374 May 5 1989 54 FR 35338 Aug 25 1989 56 FR 27426 June 14 1991 56 FR 57293 Nov 8 1991 62 FR 50256 Sept 25 1997 65 FR 79776 Dec 20 2000 87 FR 15342 Mar 18 2022 73 208 Reference points and distance computations a 1 The following reference points must be used to determine distance separation requirements when petitions to amend the Table of Allotments 73 202 b are considered i First transmitter sites if authorized or if proposed in applications with cut off protection pursuant to paragraph a 3 of this section ii Second reference coordinates designated by the FCC iii Third coordinates listed in the United States Department of Interior publication entitled Index to the National Atlas of the United States of America or iv Last coordinates of the main post office The community s reference points for which the petition is submitted will normally be the coordinates listed in the above publication 2 When the distance between communities is calculated using community reference points and it does not meet the minimum separation requirements of 73 207 the channel may still be allotted if a transmitter site is available that would meet the minimum separation requirements and still permit the proposed station to meet the minimum field strength requirements of 73 315 A showing indicating the availability of a suitable site should be sumitted with the petition In cases where a station is not authorized in a community or communities and the proposed channel cannot meet the separation requirement a showing should also be | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
made indicating adequate distance between suitable transmitter sites for all communities 3 Petitions to amend the Table of Allotments that do not meet minimum distance separation requirements to transmitter sites specified in pending applications will not be considered unless they are filed no later than 47 CFR 73 208 a 3 enhanced display page 118 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 208 a 3 i Radio Broadcast Services i The last day of a filing window if the application is for a new FM facility or a major change in the non reserved band and is filed during a filing window established under section 73 3564 d 3 or ii The cut off date established in a Commission Public Notice under 73 3564 d and 73 3573 e if the application is for a new FM facility or a major change in the reserved band or iii The date of receipt of all other types of FM applications If an application is amended so as to create a conflict with a petition for rule making filed prior to the date the amendment is filed the amended application will be treated as if filed on the date of the amendment for purposes of this paragraph a 3 Note If the filing of a conflicting FM application renders an otherwise timely filed counterproposal unacceptable the counterproposal may be considered in the rulemaking proceeding if it is amended to protect the site of the previously filed FM application within 15 days after being placed on the Public Notice routinely issued by the staff concerning the filing of counterproposals No proposals involving communities not already included in the proceeding can be introduced during the reply comment period as a method of resolving conflicts | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
The counterproponent is required to make a showing that at the time it filed the counterproposal it did not know and could not have known by exercising due diligence of the pendency of the conflicting FM application b Station separations in licensing proceedings shall be determined by the distance between the coordinates of the proposed transmitter site in one community and 1 The coordinates of an authorized transmitter site for the pertinent channel in the other community or where such transmitter site is not available for use as a reference point 2 Reference coordinates designated by the FCC or if none are designated 3 The coordinates of the other community as listed in the publication listed in paragraph a of this section or if not contained therein 4 The coordinates of the main post office of such other community 5 In addition where there are pending applications in other communities which if granted would have to be considered in determining station separations the coordinates of the transmitter sites proposed in such applications must be used to determine whether the requirements with respect to minimum separations between the proposed stations in the respective cities have been met c The method given in this paragraph shall be used to compute the distance between two reference points except that for computation of distance involving stations in Canada and Mexico the method for distance computation specified in the applicable international agreement shall be used instead The method set forth in this paragraph is valid only for distances not exceeding 475 km 295 miles 1 Convert the latitudes and longitudes of each reference point from degree minute second format to degree decimal format by dividing minutes by 60 and seconds by 3600 then adding the results to degrees 47 CFR 73 208 c 1 enhanced | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
display page 119 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 208 c 2 Radio Broadcast Services 2 Calculate the middle latitude between the two reference points by averaging the two latitudes as follows ML LAT1dd LAT2dd 2 3 Calculate the number of kilometers per degree latitude difference for the middle latitude calculated in paragraph c 2 as follows KPDlat 111 13209 0 56605 cos 2ML 0 00120 cos 4ML 4 Calculate the number of kilometers per degree longitude difference for the middle latitude calculated in paragraph c 2 as follows KPDlon 111 41513 cos ML 0 09455 cos 3ML 0 00012 cos 5ML 5 Calculate the North South distance in kilometers as follows NS KPDlat LAT1dd LAT2dd 6 Calculate the East West distance in kilometers as follows EW KPDlon LON1dd LON2dd 7 Calculate the distance between the two reference points by taking the square root of the sum of the squares of the East West and North South distances as follows DIST NS2 EW2 0 5 8 Round the distance to the nearest kilometer 9 Terms used in this section are defined as follows i LAT1dd and LON1dd the coordinates of the first reference point in degree decimal format ii LAT2dd and LON2dd the coordinates of the second reference point in degree decimal format iii ML the middle latitude in degree decimal format iv KPDlat the number of kilometers per degree of latitude at a given middle latitude v KPDlon the number of kilometers per degree of longitude at a given middle latitude vi NS the North South distance in kilometers vii EW the East West distance in kilometers viii DIST the distance between the two reference points in kilometers 28 FR 13623 Dec 14 1963 as amended at 29 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
FR 14116 Oct 14 1964 48 FR 29505 June 27 1983 52 FR 37788 Oct 9 1987 52 FR 39920 Oct 26 1987 54 FR 9806 Mar 8 1989 57 FR 36020 Aug 12 1992 58 FR 38537 July 19 1993 73 209 Protection from interference a Permittees and licensees of FM broadcast stations are not protected from any interference which may be caused by the grant of a new station or of authority to modify the facilities of an existing station in accordance with the provisions of this subpart However they are protected from interference caused by Class D secondary noncommercial educational FM stations See 73 509 47 CFR 73 209 a enhanced display page 120 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 209 b Radio Broadcast Services b The nature and extent of the protection from interference afforded FM broadcast stations operating on Channels 221 300 is limited to that which results when assignments are made in accordance with the rules in this subpart c Permittees and licensees of FM stations are not protected from interference which may be caused by the grant of a new LPFM station or of authority to modify an existing LPFM station except as provided in subpart G of this part 43 FR 39715 Sept 6 1978 and 48 FR 29505 June 27 1983 54 FR 9802 Mar 8 1989 65 FR 7640 Feb 15 2000 65 FR 67299 Nov 9 2000 73 210 Station classes a The rules applicable to a particular station including minimum and maximum facilities requirements are determined by its class Possible class designations depend upon the zone in which the station s transmitter is located or proposed to be located The zones are defined in 73 205 Allotted | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
station classes are indicated in the Table of Allotments 73 202 Class A B1 and B stations may be authorized in Zones I and I A Class A C3 C2 C1 C0 and C stations may be authorized in Zone II b The power and antenna height requirements for each class are set forth in 73 211 If a station has an ERP and an antenna HAAT such that it cannot be classified using the maximum limits and minimum requirements in 73 211 its class shall be determined using the following procedure 1 Determine the reference distance of the station using the procedure in paragraph b 1 i of 73 211 If this distance is less than or equal to 28 km the station is Class A otherwise 2 For a station in Zone I or Zone I A except for Puerto Rico and the Virgin Islands i If this distance is greater than 28 km and less than or equal to 39 km the station is Class B1 ii If this distance is greater than 39 km and less than or equal to 52 km the station is Class B 3 For a station in Zone II i If this distance is greater than 28 km and less than or equal to 39 km the station is Class C3 ii If this distance is greater than 39 km and less than or equal to 52 km the station is Class C2 iii If this distance is greater than 52 km and less than or equal to 72 km the station is Class C1 iv If this distance is greater than 72 km and less than or equal to 83 km the station is Class C0 v If this distance is greater than 83 km and less than or equal | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
to 92 km the station is Class C 4 For a station in Puerto Rico or the Virgin Islands i If this distance is less than or equal to 42 km the station is Class A ii If this distance is greater than 42 km and less than or equal to 46 km the station is Class B1 iii If this distance is greater then 46 km and less than or equal to 78 km the station is Class B 52 FR 37788 Oct 9 1987 52 FR 39920 Oct 26 1987 as amended at 54 FR 16367 Apr 24 1989 54 FR 19374 May 5 1989 54 FR 35339 Aug 25 1989 65 FR 79777 Dec 20 2000 47 CFR 73 210 b 4 iii enhanced display page 121 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 211 Radio Broadcast Services 73 211 Power and antenna height requirements a Minimum requirements 1 Except as provided in paragraphs a 3 and b 2 of this section FM stations must operate with a minimum effective radiated power ERP as follows i The minimum ERP for Class A stations is 0 1 kW ii The ERP for Class B1 stations must exceed 6 kW iii The ERP for Class B stations must exceed 25 kW iv The ERP for Class C3 stations must exceed 6 kW v The ERP for Class C2 stations must exceed 25 kW vi The ERP for Class C1 stations must exceed 50 kW vii The minimum ERP for Class C and C0 stations is 100 kW 2 Class C0 stations must have an antenna height above average terrain HAAT of at least 300 meters 984 feet Class C stations must have an antenna height above average terrain HAAT | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
of at least 451 meters 1480 feet 3 Stations of any class except Class A may have an ERP less than that specified in paragraph a 1 of this section provided that the reference distance determined in accordance with paragraph b 1 i of this section exceeds the distance to the class contour for the next lower class Class A stations may have an ERP less than 100 watts provided that the reference distance determined in accordance with paragraph b 1 i of this section equals or exceeds 6 kilometers b Maximum limits 1 Except for stations located in Puerto Rico or the Virgin Islands the maximum ERP in any direction reference HAAT and distance to the class contour for each FM station class are listed below Station class Maximum ERP Reference HAAT in meters ft Class contour distance in kilometers A 6 kW 7 8 dBk 100 328 28 B1 25 kW 14 0 dBk 100 328 39 B 50 kW 17 0 dBk 150 492 52 C3 25 kW 14 0 dBk 100 328 39 C2 50 kW 17 0 dBk 150 492 52 C1 100 kW 20 0 dBk 299 981 72 C0 100 kW 20 0 dBk 450 1476 83 C 100 kW 20 0 dBk 600 1968 92 i The reference distance of a station is obtained by finding the predicted distance to the 1mV m contour using Figure 1 of 73 333 and then rounding to the nearest kilometer Antenna HAAT is determined using the procedure in 73 313 If the HAAT so determined is less than 30 meters 100 feet a HAAT of 30 meters must be used when finding the predicted distance to the 1 mV m contour 47 CFR 73 211 b 1 i enhanced display page 122 of 580 47 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
CFR Part 73 up to date as of 2 20 2024 47 CFR 73 211 b 1 ii Radio Broadcast Services ii If a station s ERP is equal to the maximum for its class its antenna HAAT must not exceed the reference HAAT regardless of the reference distance For example a Class A station operating with 6 kW ERP may have an antenna HAAT of 100 meters but not 101 meters even though the reference distance is 28 km in both cases iii Except as provided in paragraph b 3 of this section no station will be authorized in Zone I or I A with an ERP equal to 50 kW and a HAAT exceeding 150 meters No station will be authorized in Zone II with an ERP equal to 100 kW and a HAAT exceeding 600 meters 2 If a station has an antenna HAAT greater than the reference HAAT for its class its ERP must be lower than the class maximum such that the reference distance does not exceed the class contour distance If the antenna HAAT is so great that the station s ERP must be lower than the minimum ERP for its class specified in paragraphs a 1 and a 3 of this section that lower ERP will become the minimum for that station 3 For stations located in Puerto Rico or the Virgin Islands the maximum ERP in any direction reference HAAT and distance to the class contour for each FM station class are listed below Station class Maximum ERP Reference HAAT in meters ft Class contour distance in kilometers A 6kW 7 8 dBk 240 787 42 B1 25kW 14 0 dBk 150 492 46 B 50kW 17 0 dBk 472 1549 78 c Existing stations Stations authorized prior to March 1 1984 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
that do not conform to the requirements of this section may continue to operate as authorized Stations operating with facilities in excess of those specified in paragraph b of this section may not increase their effective radiated powers or extend their 1 mV m field strength contour beyond the location permitted by their present authorizations The provisions of this section will not apply to applications to increase facilities for those stations operating with less than the minimum power specified in paragraph a of this section d Existing Class C stations below minimum antenna HAAT Class C stations authorized prior to January 19 2001 that do not meet the minimum antenna HAAT specified in paragraph a 2 of this section for Class C stations may continue to operate as authorized subject to the reclassification procedures set forth in Note 4 to 73 3573 53 FR 17042 May 13 1988 as amended at 54 FR 16367 Apr 24 1989 54 FR 19374 May 5 1989 54 FR 35339 Aug 25 1989 65 FR 79777 Dec 20 2000 73 212 Administrative changes in authorizations a In the issuance of FM broadcast station authorizations the Commission will specify the transmitter output power and effective radiated power in accordance with the following tabulation Power watts or kW Rounded out to nearest figure watts or kW 1 to 3 05 3 to 10 1 10 to 30 5 30 to 100 1 47 CFR 73 212 a enhanced display page 123 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 212 b Radio Broadcast Services Power watts or kW Rounded out to nearest figure watts or kW 100 to 300 5 300 to 1 000 10 b Antenna heights above average terrain will be rounded out to the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
nearest meter 28 FR 13623 Dec 14 1963 as amended at 48 FR 29506 June 27 1983 73 213 Grandfathered short spaced stations a Stations at locations authorized prior to November 16 1964 that did not meet the separation distances required by 73 207 and have remained continuously short spaced since that time may be modified or relocated with respect to such short spaced stations provided that i any area predicted to receive interference lies completely within any area currently predicted to receive co channel or first adjacent channel interference as calculated in accordance with paragraph a 1 of this section or that ii a showing is provided pursuant to paragraph a 2 of this section that demonstrates that the public interest would be served by the proposed changes 1 The F 50 50 curves in Figure 1 of 73 333 are to be used in conjunction with the proposed effective radiated power and antenna height above average terrain as calculated pursuant to 73 313 c d 2 and d 3 using data for as many radials as necessary to determine the location of the desired service field strength The F 50 10 curves in Figure 1a of 73 333 are to be used in conjunction with the proposed effective radiated power and antenna height above average terrain as calculated pursuant to 73 313 c d 2 and d 3 using data for as many radials as necessary to determine the location of the undesired interfering field strength Predicted interference is defined to exist only for locations where the desired service field strength exceeds 0 5 mV m 54 dBu for a Class B station 0 7 mV m 57 dBu for a Class B1 station and 1 mV m 60 dBu for any other class of station i Co | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
channel interference is predicted to exist for the purpose of this section at all locations where the undesired interfering station F 50 10 field strength exceeds a value 20 dB below the desired service F 50 50 field strength of the station being considered e g where the protected field strength is 60 dBu the interfering field strength must be 40 dBu or more for predicted interference to exist ii First adjacent channel interference is predicted to exist for the purpose of this section at all locations where the undesired interfering station F 50 10 field strength exceeds a value 6 dB below the desired service F 50 50 field strength of the station being considered e g where the protected field strength is 60 dBu the interfering field strength must be 54 dBu or more for predicted interference to exist 2 For co channel and first adjacent channel stations a showing that the public interest would be served by the changes proposed in an application must include exhibits demonstrating that the total area and population subject to co channel or first adjacent channel interference caused and received would be maintained or decreased In addition the showing must include exhibits demonstrating that the area and the population subject to co channel or first adjacent channel interference caused by the proposed facility to each short spaced station individually is not 47 CFR 73 213 a 2 enhanced display page 124 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 213 a 3 Radio Broadcast Services increased In all cases the applicant must also show that any area predicted to lose service as a result of new co channel or first adjacent channel interference has adequate aural service remaining For the purpose of this | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
section adequate service is defined as 5 or more aural services AM or FM 3 For co channel and first adjacent channel stations a copy of any application proposing interference caused in any areas where interference is not currently caused must be served upon the licensee s of the affected short spaced station s 4 For stations covered by this paragraph a there are no distance separation or interference protection requirements with respect to second adjacent and third adjacent channel short spacings that have existed continuously since November 16 1964 b Stations at locations authorized prior to May 17 1989 that did not meet the IF separation distances required by 73 207 and have remained short spaced since that time may be modified or relocated provided that the overlap area of the two stations 36 mV m field strength contours is not increased c Short spacings involving at least one Class A allotment or authorization Stations that became short spaced on or after November 16 1964 including stations that do not meet the minimum distance separation requirements of paragraph c 1 of this section and that propose to maintain or increase their existing distance separations may be modified or relocated in accordance with paragraph c 1 or c 2 of this section except that this provision does not apply to stations that became short spaced by grant of applications filed after October 1 1989 or filed pursuant to 73 215 If the reference coordinates of an allotment are short spaced to an authorized facility or another allotment as a result of the revision of 73 207 in the Second Report and Order in MM Docket No 88 375 an application for the allotment may be authorized and subsequently modified after grant in accordance with paragraph c 1 or c 2 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
of this section only with respect to such short spacing No other stations will be authorized pursuant to these paragraphs 1 Applications for authorization under requirements equivalent to those of prior rules Each application for authority to operate a Class A station with no more than 3000 watts ERP and 100 meters antenna HAAT or equivalent lower ERP and higher antenna HAAT based on a class contour distance of 24 km must specify a transmitter site that meets the minimum distance separation requirements in this paragraph Each application for authority to operate a Class A station with more than 3000 watts ERP up to a maximum of 5800 watts but with an antenna HAAT lower than 100 meters such that the distance to the predicted 0 05 mV m 34 dBµV m F 50 10 field strength contour does not exceed 98 km must specify a transmitter site that meets the minimum distance separation requirements in this paragraph Each application for authority to operate an FM station of any class other than Class A must specify a transmitter site that meets the minimum distance separation requirements in this paragraph with respect to Class A stations operating pursuant to this paragraph or paragraph c 2 of this section and that meets the minimum distance separation requirements of 73 207 with respect to all other stations Minimum Distance Separation Requirements in Kilometers miles Relation Co channel 200 kHz 400 600 kHz 10 6 10 8 MHz A to A 105 65 64 40 27 17 8 5 A to B1 138 86 88 55 48 30 11 6 A to B 163 101 105 65 69 43 14 9 A to C3 138 86 84 52 42 26 11 6 47 CFR 73 213 c 1 enhanced display page 125 of 580 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 213 c 2 Radio Broadcast Services Relation Co channel 200 kHz 400 600 kHz 10 6 10 8 MHz A to C2 163 101 105 65 55 34 14 9 A to C1 196 122 129 80 74 46 21 13 A to C 222 138 161 100 94 58 28 17 2 Applications for authorization of Class A facilities greater than 3 000 watts ERP and 100 meters HAAT Each application to operate a Class A station with an ERP and HAAT such that the reference distance would exceed 24 kilometers must contain an exhibit demonstrating the consent of the licensee of each co channel first second or third adjacent channel station for which the requirements of 73 207 are not met to a grant of that application Each such application must specify a transmitter site that meets the applicable IF related channel distance separation requirements of 73 207 Applications that specify a new transmitter site which is short spaced to an FM station other than another Class A station which is seeking a mutual increase in facilities may be granted only if no alternative fully spaced site or less short spaced site is available Licensees of Class A stations seeking mutual increases in facilities need not show that a fully spaced site or less short spaced site is available Applications submitted pursuant to the provisions of this paragraph may be granted only if such action is consistent with the public interest 52 FR 37789 Oct 9 1987 as amended at 54 FR 14964 Apr 14 1989 54 FR 35339 Aug 25 1989 56 FR 27426 June 14 1991 62 FR 50521 Sept 26 1997 63 FR 33876 June 22 1998 73 215 Contour | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
protection for short spaced assignments The Commission will accept applications that specify short spaced antenna locations locations that do not meet the domestic co channel and adjacent channel minimum distance separation requirements of 73 207 Provided That such applications propose contour protection as defined in paragraph a of this section with all short spaced assignments applications and allotments and meet the other applicable requirements of this section Each application to be processed pursuant to this section must specifically request such processing on its face and must include the necessary exhibit to demonstrate that the requisite contour protection will be provided Such applications may be granted when the Commission determines that such action would serve the public interest convenience and necessity a Contour protection Contour protection for the purpose of this section means that on the same channel and on the first second and third adjacent channels the predicted interfering contours of the proposed station do not overlap the predicted protected contours of other short spaced assignments applications and allotments and the predicted interfering contours of other short spaced assignments applications and allotments do not overlap the predicted protected contour of the proposed station 1 The protected contours for the purpose of this section are defined as follows For all Class B and B1 stations on Channels 221 through 300 inclusive the F 50 50 field strengths along the protected contours are 0 5 mV m 54 dBµ and 0 7 mV m 57 dBµ respectively For all other stations the F 50 50 field strength along the protected contour is 1 0 mV m 60 dBµ 2 The interfering contours for the purpose of this section are defined as follows For co channel stations the F 50 10 field strength along the interfering contour is 20 dB lower than the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
F 50 50 field strength along the protected contour for which overlap is prohibited For first adjacent channel stations 200 kHz the F 50 10 field strength along the interfering contour is 6 dB lower than the F 50 50 field strength along the protected contour for which overlap is prohibited For both second 47 CFR 73 215 a 2 enhanced display page 126 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 215 a 3 Radio Broadcast Services and third adjacent channel stations 400 kHz and 600 kHz the F 50 10 field strength along the interfering contour is 40 dB higher than the F 50 50 field strength along the protected contour for which overlap is prohibited 3 The locations of the protected and interfering contours of the proposed station and the other short spaced assignments applications and allotments must be determined in accordance with the procedures of paragraphs c d 2 and d 3 of 73 313 using data for as many radials as necessary to accurately locate the contours 4 Protected and interfering contours in dBu for stations in Puerto Rico and the U S Virgin Islands are as follows Station with protected contour Station with interfering contour Class A Class B1 Class B Interfering Protected Interfering Protected Interfering Protected Co Channel Class A 46 66 41 61 40 60 Class B1 43 63 39 59 38 58 Class B 45 65 41 61 41 61 1st Adj Channel Class A 61 67 56 62 59 65 Class B1 57 63 54 60 54 60 Class B 62 68 56 62 57 63 2nd 3rd Adj Channel Class A 107 67 100 60 104 64 Class B1 99 59 100 60 104 64 Class B 94 54 94 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
54 104 64 Maximum permitted facilities assumed for each station pursuant to 47 CFR 73 211 b 3 6 kW ERP 240 meters HAAT Class A 25 kW ERP 150 meters HAAT Class B1 50 kW ERP 472 meters HAAT Class B b Applicants requesting short spaced assignments pursuant to this section must take into account the following factors in demonstrating that contour protection is achieved 1 The ERP and antenna HAAT of the proposed station in the direction of the contours of other short spaced assignments applications and allotments If a directional antenna is proposed the pattern of that antenna must be used to calculate the ERP in particular directions See 73 316 for additional requirements for directional antennas 2 The ERP and antenna HAAT of other short spaced assignments applications and allotments in the direction of the contours of the proposed station The ERP and antenna HAATs in the directions of concern must be determined as follows 47 CFR 73 215 b 2 enhanced display page 127 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 215 b 2 i Radio Broadcast Services i For vacant allotments contours are based on the presumed use at the allotment s reference point of the maximum ERP that could be authorized for the station class of the allotment and antenna HAATs in the directions of concern that would result from a non directional antenna mounted at a standard eight radial antenna HAAT equal to the reference HAAT for the station class of the allotment ii For existing stations that were not authorized pursuant to this section including stations with authorized ERP that exceeds the maximum ERP permitted by 73 211 for the standard eight radial antenna HAAT employed and for applications not requesting | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
authorization pursuant to this section contours are based on the presumed use of the maximum ERP for the applicable station class as specified in 73 211 and the antenna HAATs in the directions of concern that would result from a non directional antenna mounted at a standard eight radial antenna HAAT equal to the reference HAAT for the applicable station class without regard to any other restrictions that may apply e g zoning laws FAA constraints application of 73 213 iii For stations authorized pursuant to this section except stations with authorized ERP that exceeds the maximum ERP permitted by 73 211 for the standard eight radial antenna HAAT employed contours are based on the use of the authorized ERP in the directions of concern and HAATs in the directions of concern derived from the authorized standard eight radial antenna HAAT For stations with authorized ERP that exceeds the maximum ERP permitted by 73 211 for the standard eight radial antenna HAAT employed authorized under this section contours are based on the presumed use of the maximum ERP for the applicable station class as specified in 73 211 and antenna HAATs in the directions of concern that would result from a non directional antenna mounted at a standard eight radial antenna HAAT equal to the reference HAAT for the applicable station class without regard to any other restrictions that may apply iv For applications containing a request for authorization pursuant to this section except for applications to continue operation with authorized ERP that exceeds the maximum ERP permitted by 73 211 for the standard eight radial antenna HAAT employed contours are based on the use of the proposed ERP in the directions of concern and antenna HAATs in the directions of concern derived from the proposed standard eight radial antenna | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
HAAT For applications to continue operation with an ERP that exceeds the maximum ERP permitted by 73 211 for the standard eight radial HAAT employed if processing is requested under this section contours are based on the presumed use of the maximum ERP for the applicable station class as specified in 73 211 and antenna HAATs in the directions of concern that would result from a nondirectional antenna mounted at a standard eight radial antenna HAAT equal to the reference HAAT for the applicable station class without regard to any other restrictions that may apply Note to paragraph b Applicants are cautioned that the antenna HAAT in any particular direction of concern will not usually be the same as the standard eight radial antenna HAAT or the reference HAAT for the station class 47 CFR 73 215 b 2 iv enhanced display page 128 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 215 c Radio Broadcast Services c Applications submitted for processing pursuant to this section are not required to propose contour protection of any assignment application or allotment for which the minimum distance separation requirements of 73 207 are met and may in the directions of those assignments applications and allotments employ the maximum ERP permitted by 73 211 for the standard eight radial antenna HAAT employed d Stations authorized pursuant to this section may be subsequently authorized on the basis of compliance with the domestic minimum separation distance requirements of 73 207 upon filing of an FCC Form 301 or FCC Form 340 as appropriate requesting a modification of authorization e The Commission will not accept applications that specify a short spaced antenna location for which the following minimum distance separation requirements in kilometers miles are not met Relation | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
Co Channel 200 kHz 400 600 kHz A to A 92 57 49 30 25 16 A to B1 119 74 72 45 42 26 A to B 143 89 96 60 63 39 A to C3 119 74 72 45 36 22 A to C2 143 89 89 55 49 30 A to C1 178 111 111 69 69 43 A to C0 193 120 130 81 80 50 A to C 203 126 142 88 89 55 B1 to B1 143 89 96 60 44 27 B1 to B 178 111 114 71 65 40 B1 to C3 143 89 96 60 44 27 B1 to C2 175 109 114 71 50 31 B1 to C1 200 124 134 83 71 44 B1 to C0 0215 134 153 95 81 50 B1 to C 233 145 165 103 99 61 B to B 211 131 145 90 68 42 B to C3 178 111 114 70 65 40 B to C2 211 131 145 90 68 42 B to C1 241 150 169 105 73 45 B to C0 266 165 195 121 83 52 B to C 268 163 195 121 99 61 C3 to C3 142 88 89 55 37 23 C3 to C2 166 103 106 66 50 31 C3 to C1 200 124 133 83 70 43 C3to C0 215 134 152 94 81 50 C3 to C 226 140 165 103 90 56 C2 to C2 177 110 117 73 52 32 C2 to C1 211 131 144 90 73 45 C2 to C0 227 141 163 101 83 52 C2 to C 237 147 176 109 96 61 47 CFR 73 215 e enhanced display page 129 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
CFR 73 220 Radio Broadcast Services Relation Co Channel 200 kHz 400 600 kHz C1 to C1 224 139 158 98 76 47 C1 to C0 239 148 176 109 88 55 C1 to C 249 155 188 117 99 61 C0 to C0 259 161 196 122 90 56 C0 to C 270 168 207 129 99 61 C to C 270 168 209 130 99 61 54 FR 9802 Mar 8 1989 as amended at 54 FR 35340 Aug 25 1989 56 FR 57294 Nov 8 1991 57 FR 46325 Oct 8 1992 65 FR 79777 Dec 20 2000 66 FR 8149 Jan 29 2001 73 220 Restrictions on use of channels a The frequency 89 1 MHz channel 206 is revised in the New York City metropolitan area for the use of the United Nations with the equivalent of an antenna height of 150 meters 492 feet above average terrain and effective radiated power of 20 kWs and the FCC will make no assignments which would cause objectionable interference with such use b Reserved 43 FR 45845 Oct 4 1978 as amended at 46 FR 50376 Oct 13 1981 47 FR 30068 July 12 1982 48 FR 29507 June 27 1983 70 FR 46676 Aug 10 2005 73 232 Territorial exclusivity No licensee of an FM broadcast station shall have any arrangement with a network organization which prevents or hinders another station serving substantially the same area from broadcasting the network s programs not taken by the former station or which prevents or hinders another station serving a substantially different area from broadcasting any program of the network organization Provided however That this section does not prohibit arrangements under which the station is granted first call within its primary service area upon the network s programs The | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
term network organization means any organization originating program material with or without commercial messages and furnishing the same to stations interconnected so as to permit simultaneous broadcast by all or some of them However arrangements involving only stations under common ownership or only the rebroadcast by one station of programming from another with no compensation other than a lump sum payment by the station rebroadcasting are not considered arrangements with a network organization The term arrangement means any contract arrangement or understanding express or implied 42 FR 16422 Mar 28 1977 as amended at 57 FR 48333 Oct 23 1992 73 258 Indicating instruments a Each FM broadcast station shall be equipped with indicating instruments which conform with the specifications described in 73 1215 for determining power by the indirect method for indicating the relative amplitude of the transmission line radio frequency current voltage or power and with such other instruments as are necessary for the proper adjustment operation and maintenance of the transmitting system b The function of each instrument shall be clearly and permanently shown in the instrument itself or on the panel immediately adjacent thereto 47 CFR 73 258 b enhanced display page 130 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 258 c Radio Broadcast Services c In the event that any one of these indicating instruments becomes defective when no substitute which conforms with the required specifications is available the station may be operated without the defective instrument pending its repair or replacement for a period not in excess of 60 days without further authority of the FCC Provided that if the defective instrument is the transmission line meter of a station which determines the output power by the direct method the operating power shall be | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
determined by the indirect method in accordance with 73 267 c during the entire time the station is operated without the transmission line meter d If conditions beyond the control of the licensee prevent the restoration of the meter to service within the above allowed period an informal letter request in accordance with 73 3549 may be filed with the FCC Attention Audio Division Media Bureau in Washington DC for such additional time as may be required to complete repairs of the defective instrument 41 FR 36818 Sept 1 1976 as amended at 48 FR 44805 Sept 30 1983 50 FR 32416 Aug 12 1985 63 FR 33876 June 22 1998 67 FR 13231 Mar 21 2002 73 267 Determining operating power a The operating power of each FM station is to be determined by either the direct or indirect method b Direct method The direct method of power determination for an FM station uses the indications of a calibrated transmission line meter responsive to relative voltage current or power located at the RF output terminals of the transmitter This meter must be calibrated whenever there is any indication that the calibration is inaccurate or whenever any component of the metering circuit is repaired or replaced The calibration must cover as a minimum the range from 90 to 105 of authorized power The meter calibration may be checked by measuring the power at the transmitter terminals while either 1 Operating the transmitter into the transmitting antenna and determining actual operating power by the indirect method described in 73 267 c or 2 Operating the transmitter into a load of substantially zero reactance and a resistance equal to the transmission line characteristic impedance and using an electrical device within 5 accuracy or temperature and coolant flow indicator within 4 accuracy to | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
determine the power 3 The calibration must cover as a minimum the range from 90 to 105 of authorized power and the meter must provide clear indications which will permit maintaining the operating power within the prescribed tolerance or the meter shall be calibrated to read directly in power units c Indirect method The operating power is determined by the indirect method by applying an appropriate factor to the input power to the last radio frequency power amplifier stage of the transmitter using the following formula Transmitter output power Ep Ip F Where Ep DC input voltage of final radio stage Ip Total DC input current of final radio stage F Efficiency factor 47 CFR 73 267 c enhanced display page 131 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 267 c 1 Radio Broadcast Services 1 If the above formula is not appropriate for the design of the transmitter final amplifier use a formula specified by the transmitter manufacturer with other appropriate operating parameters 2 The value of the efficiency factor F established for the authorized transmitter output power is to be used for maintaining the operating power even though there may be some variation in F over the power operating range of the transmitter 3 The value of F is to be determined and a record kept thereof by one of the following procedures listed in order of preference i Using the most recent measurement data for calibration of the transmission line meter according to the procedures described in paragraph b of this section or the most recent measurements made by the licensee establishing the value of F In the case of composite transmitters or those in which the final amplifier stages have been modified pursuant to FCC approval | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
the licensee must furnish the FCC and also retain with the station records the measurement data used as a basis for determining the value of F ii Using measurement data shown on the transmitter manufacturer s test data supplied to the licensee Provided That measurements were made at the authorized frequency and transmitter output power iii Using the transmitter manufacturer s measurement data submitted to the FCC for type acceptance and as shown in the instruction book supplied to the licensee Secs 4 5 303 48 Stat as amended 1066 1068 1082 47 U S C 154 155 303 44 FR 58731 Oct 11 1979 as amended at 45 FR 28141 Apr 28 1980 48 FR 38479 Aug 24 1983 49 FR 4210 Feb 3 1984 49 FR 49851 Dec 24 1984 73 277 Permissible transmissions a No FM broadcast licensee or permittee shall enter into any agreement arrangement or understanding oral or written whereby it undertakes to supply or receives consideration for supplying on its main channel a functional music background music or other subscription service including storecasting for reception in the place or places of business of any subscriber b The transmission or interruption of radio energy in the FM broadcast band is permissible only pursuant to a station license program test authority construction permit or experimental authorization and the provisions of this part of the rules 29 FR 7471 June 10 1964 Redesignated at 39 FR 38655 Nov 1 1974 and amended at 48 FR 28454 June 22 1983 73 293 Use of FM multiplex subcarriers Licensees of FM broadcast stations may transmit without further authorization subcarrier communication services in accordance with the provisions of 73 319 and 73 322 51 FR 17028 May 8 1986 47 CFR 73 293 enhanced display page 132 of 580 47 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
CFR Part 73 up to date as of 2 20 2024 47 CFR 73 295 Radio Broadcast Services 73 295 FM subsidiary communications services a Subsidiary communication services are those transmitted on a subcarrier within the FM baseband signal but do not include services which enhance the main program broadcast service or exclusively relate to station operations see 73 293 Subsidiary communications include but are not limited to services such as functional music specialized foreign language programs radio reading services utility load management market and financial data and news paging and calling traffic control signal switching bilingual television audio and point to point or multipoint messages b FM subsidiary communications services that are common carrier in nature are subject to common carrier regulation Licensees operating such services are required to apply to the FCC for the appropriate authorization and to comply with all policies and rules applicable to the service Responsibility for making the initial determinations of whether a particular activity is common carriage rests with the FM station licensee Initial determinations by licensees are subject to FCC examination and may be reviewed at the FCC s discretion c Subsidiary communications services are of a secondary nature under the authority of the FM station authorization and the authority to provide such communications services may not be retained or transferred in any manner separate from the station s authorization The grant or renewal of an FM station permit or license is not furthered or promoted by proposed or past services The permittee or licensee must establish that the broadcast operation is in the public interest wholly apart from the subsidiary communications services provided d The station identification delayed recording and sponsor identification announcements required by 73 1201 73 1208 and 73 1212 are not applicable to material transmitted under an SCA | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
e The licensee or permittee must retain control over all material transmitted in a broadcast mode via the station s facilities with the right to reject any material that it deems inappropriate or undesirable 48 FR 28454 June 22 1983 as amended at 48 FR 44805 Sept 30 1983 49 FR 33663 Aug 15 1984 50 FR 32416 Aug 12 1985 57 FR 48333 Oct 23 1992 73 297 FM stereophonic sound broadcasting a An FM broadcast station may without specific authority from the FCC transmit stereophonic biphonic quadraphonic etc sound programs upon installation of stereophonic sound transmitting equipment under the provisions of 2 1001 73 322 and 73 1590 of the Rules Prior to commencement of stereophonic sound broadcasting equipment performance measurements must be made to ensure that the transmitted signal complies with all applicable rules and standards b Each licensee or permittee engaging in multichannel broadcasting must measure the pilot subcarrier frequency as often as necessary to ensure that it is kept at all times within 2 Hz of the authorized frequency 48 FR 28454 June 22 1983 and 48 FR 38479 Aug 24 1983 73 310 FM technical definitions a Frequency modulation Antenna height above average terrain HAAT HAAT is calculated by determining the average of the antenna heights above the terrain from 3 to 16 kilometers 2 to 10 miles from the antenna for the eight directions evenly spaced for each 45 of azimuth starting with True North a 47 CFR 73 310 a enhanced display page 133 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 310 a Antenna power gain Radio Broadcast Services different antenna height will be determined in each direction from the antenna and computing the average of these separate heights In some cases | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
less than eight directions may be used See 73 313 d Where circular or elliptical polarization is used the antenna height above average terrain must be based upon the height of the radiation of the antenna that transmits the horizontal component of radiation Antenna power gain The square of the ratio of the root mean square RMS free space field strength produced at 1 kilometer in the horizontal plane in millivolts per meter for 1 kW antenna input power to 221 4 mV m This ratio is expressed in decibels dB If specified for a particular direction antenna power gain is based on that field strength in the direction only Auxiliary facility An auxiliary facility is an antenna separate from the main facility s antenna permanently installed on the same tower or at a different location from which a station may broadcast for short periods without prior Commission authorization or notice to the Commission while the main facility is not in operation e g where tower work necessitates turning off the main antenna or where lightning has caused damage to the main antenna or transmission system See 73 1675 Center frequency The term center frequency means 1 The average frequency of the emitted wave when modulated by a sinusoidal signal 2 The frequency of the emitted wave without modulation Composite antenna pattern The composite antenna pattern is a relative field horizontal plane pattern for 360 degrees of azimuth for which the value at a particular azimuth is the greater of the horizontally polarized or vertically polarized component relative field values The composite antenna pattern is normalized to a maximum of unity 1 000 relative field Composite baseband signal A signal which is composed of all program and other communications signals that frequency modulates the FM carrier Effective radiated power The | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
term effective radiated power means the product of the antenna power transmitter output power less transmission line loss times 1 The antenna power gain or 2 the antenna field gain squared Where circular or elliptical polarization is employed the term effective radiated power is applied separately to the horizontal and vertical components of radiation For allocation purposes the effective radiated power authorized is the horizontally polarized component of radiation only Equivalent isotropically radiated power EIRP The term equivalent isotropically radiated power also known as effective radiated power above isotropic means the product of the antenna input power and the antenna gain in a given direction relative to an isotropic antenna FM Blanketing Blanketing is that form of interference to the reception of other broadcast stations which is caused by the presence of an FM broadcast signal of 115 dBu 562 mV m or greater signal strength in the area adjacent to the antenna of the transmitting station The 115 dBu contour is referred to as the blanketing contour and the area within this contour is referred to as the blanketing area FM broadcast band The band of frequencies extending from 88 to 108 MHz which includes those assigned to noncommercial educational broadcasting 47 CFR 73 310 a FM broadcast band enhanced display page 134 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 310 a FM broadcast channel Radio Broadcast Services FM broadcast channel A band of frequencies 200 kHz wide and designated by its center frequency Channels for FM broadcast stations begin at 88 1 MHz and continue in successive steps of 200 kHz to and including 107 9 MHz FM broadcast station A station employing frequency modulation in the FM broadcast band and licensed primarily for the transmission of radiotelephone | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
emissions intended to be received by the general public Field strength The electric field strength in the horizontal plane Free space field strength The field strength that would exist at a point in the absence of waves reflected from the earth or other reflecting objects Frequency departure The amount of variation of a carrier frequency or center frequency from its assigned value Frequency deviation The peak difference between modulated wave and the carrier frequency Frequency modulation A system of modulation where the instantaneous radio frequency varies in proportion to the instantaneous amplitude of the modulating signal amplitude of modulating signal to be measured after pre emphasis if used and the instantaneous radio frequency is independent of the frequency of the modulating signal Frequency swing The peak difference between the maximum and the minimum values of the instantaneous frequency of the carrier wave during modulation Multiplex transmission The term multiplex transmission means the simultaneous transmission of two or more signals within a single channel Multiplex transmission as applied to FM broadcast stations means the transmission of facsimile or other signals in addition to the regular broadcast signals Percentage modulation The ratio of the actual frequency deviation to the frequency deviation defined as 100 modulation expressed in percentage For FM broadcast stations a frequency deviation of 75kHz is defined as 100 modulation b Stereophonic sound broadcasting Cross talk An undesired signal occurring in one channel caused by an electrical signal in another channel FM stereophonic broadcast The transmission of a stereophonic program by a single FM broadcast station utilizing the main channel and a stereophonic subchannel Left or right signal The electrical output of a microphone or combination of microphones placed so as to convey the intensity time and location of sounds originating predominately to the listener s left or right of | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
the center of the performing area Left or right stereophonic channel The left or right signal as electrically reproduced in reception of FM stereophonic broadcasts Main channel The band of frequencies from 50 to 15 000 Hz which frequency modulate the main carrier Pilot subcarrier A subcarrier that serves as a control signal for use in the reception of FM stereophonic sound broadcasts 47 CFR 73 310 b enhanced display page 135 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 310 b Radio Broadcast Services Stereophonic separation The ratio of the electrical signal caused in sound channel A to the signal caused in sound channel B by the transmission of only a channel B signal Channels A and B may be any two channels of a stereophonic sound broadcast transmission system Stereophonic sound The audio information carried by plurality of channels arranged to afford the listener a sense of the spatial distribution of sound sources Stereophonic sound broadcasting includes but is not limited to biphonic two channel triphonic three channel and quadrophonic four channel program services Stereophonic sound subcarrier A subcarrier within the FM broadcast baseband used for transmitting signals for stereophonic sound reception of the main broadcast program service Stereophonic sound subchannel The band of frequencies from 23 kHz to 99 kHz containing sound subcarriers and their associated sidebands c Visual transmissions Communications or message transmitted on a subcarrier intended for reception and visual presentation on a viewing screen teleprinter facsimile printer or other form of graphic display or record d Control and telemetry transmissions Signals transmitted on a multiplex subcarrier intended for any form of control and switching functions or for equipment status data and aural or visual alarms 28 FR 13623 Dec 14 1963 as amended at 39 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
FR 10575 Mar 21 1974 44 FR 36038 June 20 1979 48 FR 28454 June 22 1983 48 FR 29507 June 27 1983 48 FR 37216 Aug 17 1983 49 FR 45145 Nov 15 1984 57 FR 48333 Oct 23 1992 62 FR 51058 Sept 30 1997 73 311 Field strength contours a Applications for FM broadcast authorizations must show the field strength contours required by FCC Form 301 or FCC Form 340 as appropriate b The field strength contours provided for in this section shall be considered for the following purposes only 1 In the estimation of coverage resulting from the selection of a particular transmitter site by an applicant for an FM broadcast station 2 In connection with problems of coverage arising out of application of 73 3555 3 In determining compliance with 73 315 a concerning the minimum field strength to be provided over the principal community to be served 4 In determining compliance with 73 215 concerning contour protection 28 FR 13623 Dec 14 1963 as amended at 31 FR 10126 July 27 1966 32 FR 11471 Aug 9 1967 52 FR 10570 Apr 2 1987 54 FR 9802 Mar 8 1989 73 312 Topographic data a In the preparation of the profile graphs previously described and in determining the location and height above mean sea level of the antenna site the elevation or contour intervals shall be taken from United States Geological Survey Topographic Quadrangle Maps United States Army Corps of Engineers Maps or Tennessee Valley Authority maps whichever is the latest for all areas for which such maps are available 47 CFR 73 312 a enhanced display page 136 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 312 b Radio Broadcast Services If such maps | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
are not published for the area in question the next best topographic information should be used Topographic data may sometimes be obtained from state and municipal agencies The data from the Sectional Aeronautical Charts including bench marks or railroad depot elevations and highway elevations from road maps may be used where no better information is available In cases where limited topographic data can be obtained use may be made of an altimeter in a car driven along roads extending generally radially from the transmitter site b The Commission will not ordinarily require the submission of topographical maps for areas beyond 24 km 15 miles from the antenna site but the maps must include the principal city or cities to be served If it appears necessary additional data may be requested c The U S Geological Survey Topography Quadrangle Sheets may be obtained from the U S Geological Survey Department of the Interior Washington DC 20240 The Sectional Aeronautical Charts are available from the U S Coast and Geodetic Survey Department of Commerce Washington DC 20235 These maps may also be secured from branch offices and from authorized agents or dealers in most principal cities d In lieu of maps the average terrain elevation may be computer generated except in cases of dispute using elevations from a 30 second point or better topographic data file The file must be identified and the data processed for intermediate points along each radial using linear interpolation techniques The height above mean sea level of the antenna site must be obtained manually using appropriate topographic maps 28 FR 13623 Dec 14 1963 as amended at 31 FR 10126 July 27 1966 49 FR 48937 Dec 17 1984 58 FR 44950 Aug 25 1993 63 FR 33877 June 22 1998 73 313 Prediction of coverage a | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
All predictions of coverage made pursuant to this section shall be made without regard to interference and shall be made only on the basis of estimated field strengths b Predictions of coverage shall be made only for the same purposes as relate to the use of field strength contours as specified in 73 311 c In predicting the distance to the field strength contours the F 50 50 field strength chart Figure 1 of 73 333 must be used The 50 field strength is defined as that value exceeded for 50 of the time 1 The F 50 50 chart gives the estimated 50 field strengths exceeded at 50 of the locations in dB above 1 uV m The chart is based on an effective power radiated from a half wave dipole antenna in free space that produces an unattenuated field strength at 1 kilometer of about 107 dB above 1 uV m 221 4 mV m 2 To use the chart for other ERP values convert the ordinate scale by the appropriate adjustment in dB For example the ordinate scale for an ERP of 50 kW should be adjusted by 17 dB 10 log 50 kW 17 dBk and therefore a field strength of 60 dBu would correspond to the field strength value at 60 17 44 dBu on the chart When predicting the distance to field strength contours use the maximum ERP of the main radiated lobe in the pertinent azimuthal direction do not account for beam tilt When predicting field strengths over areas not in the plane of the maximum main lobe use the ERP in the direction of such areas determined by considering the appropriate vertical radiation pattern 47 CFR 73 313 c 2 enhanced display page 137 of 580 47 CFR Part 73 up to | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
date as of 2 20 2024 47 CFR 73 313 d Radio Broadcast Services d The antenna height to be used with this chart is the height of the radiation center of the antenna above the average terrain along the radial in question In determining the average elevation of the terrain the elevations between 3 and 16 kilometers from the antenna site are used 1 Profile graphs must be drawn for eight radials beginning at the antenna site and extending 16 kilometers therefrom The radials should be drawn for each 45 of azimuth starting with True North At least one radial must include the principal community to be served even though it may be more than 16 kilometers from the antenna site However in the event none of the evenly spaced radials include the principal community to be served and one or more such radials are drawn in addition these radials must not be used in computing the antenna height above average terrain 2 Where the 3 to 16 kilometers portion of a radial extends in whole or in part over a large body of water or extends over foreign territory but the 50 uV m 34 dBu contour encompasses land area within the United States beyond the 16 kilometers portion of the radial the entire 3 to 16 kilometers portion of the radial must be included in the computation of antenna height above average terrain However where the 50 uV m 34 dBu contour does not so encompass United States land area and i the entire 3 to 16 kilometers portion of the radial extends over large bodies of water or over foreign territory such radial must be completely omitted from the computation of antenna height above average terrain and ii where a part of the 3 to 16 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
kilometers portion of a radial extends over large bodies of water or foreign territory only that part of the radial extending from 3 kilometers to the outermost portion of land in the United States covered by the radial used must be used in the computation of antenna height above average terrain 3 The profile graph for each radial should be plotted by contour intervals of from 12 to 30 meters and where the data permits at least 50 points of elevation generally uniformly spaced should be used for each radial In instances of very rugged terrain where the use of contour intervals of 30 meters would result in several points in a short distance 60 or 120 meter contour intervals may be used for such distances On the other hand where the terrain is uniform or gently sloping the smallest contour interval indicated on the topographic map should be used although only relatively few points may be available The profile graph should indicate the topography accurately for each radial and the graphs should be plotted with the distance in kilometers as the abscissa and the elevation in meters above mean sea level as the ordinate The profile graphs should indicate the source of the topographical data used The graph should also show the elevation of the center of the radiating system The graph may be plotted either on rectangular coordinate paper or on special paper that shows the curvature of the earth It is not necessary to take the curvature of the earth into consideration in this procedure as this factor is taken care of in the charts showing signal strengths The average elevation of the 13 kilometer distance between 3 and 16 kilometers from the antenna site should then be determined from the profile graph for each radial This | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
may be obtained by averaging a large number of equally spaced points by using a planimeter or by obtaining the median elevation that exceeded for 50 of the distance in sectors and averaging those values 4 Examples of HAAT calculations i The heights above average terrain on the eight radials are as follows Meters 0 120 47 CFR 73 313 d 4 i enhanced display page 138 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 313 d 4 ii Radio Broadcast Services Meters 45 255 90 185 135 90 180 10 225 85 270 40 315 85 The antenna height above terrain defined in 73 310 a is computed as follows 120 255 185 90 10 85 40 85 8 85 meters ii Same as paragraph d 4 i of this section except the 0 radial is entirely over sea water The antenna height above average terrain is computed as follows note that the divisor is 7 not 8 255 185 90 10 85 40 85 7 80 meters iii Same as paragraph d 4 i of this section except that only the first 10 kilometers of the 90 radial are in the United States beyond 10 kilometers the 90 radial is in a foreign country The height above average terrain of the 3 to 10 kilometer portion of the 90 radial is 105 meters The antenna height above average terrain is computed as follows note that the divisor is 8 not 7 5 120 255 105 90 10 85 40 85 8 75 meters e In cases where the terrain in one or more directions from the antenna site departs widely from the average elevation of the 3 to 16 kilometer sector the prediction method may indicate contour distances that | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
are different from what may be expected in practice For example a mountain ridge may indicate the practical limit of service although the prediction method may indicate otherwise In such cases the prediction method should be followed but a supplemental showing may be made concerning the contour distances as determined by other means Such supplemental showings should describe the procedure used and should include sample calculations Maps of predicted coverage should include both the coverage as predicted by the regular method and as predicted by a supplemental method When measurements of area are required these should include the area obtained by the regular prediction method and the area obtained by the supplemental method In directions where the terrain is such that antenna heights less than 30 meters for the 3 to 16 kilometer sector are obtained an assumed height of 30 meters must be used for the prediction of coverage However where the actual contour distances are critical factors a supplemental showing of expected coverage must be included together with a description of the method used in predicting such coverage In special cases the FCC may require additional information as to terrain and coverage f The effect of terrain roughness on the predicted field strength of a signal at points distant from an FM transmitting antenna is assumed to depend on the magnitude of a terrain roughness factor h which for a specific propagation path is determined by the characteristics of a segment of the terrain profile for that path 40 kilometers in length located between 10 and 50 kilometers from the antenna The terrain roughness factor has a value equal to the distance in meters between elevations exceeded by all points on the profile for 10 and 90 respectively of the length of the profile segment See 73 333 | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
Figure 4 g If the lowest field strength value of interest is initially predicted to occur over a particular propagation path at a distance that is less than 50 kilometers from the antenna the terrain profile segment used in the determination of terrain roughness factor over that path must be that included between points 10 47 CFR 73 313 g enhanced display page 139 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 313 h Radio Broadcast Services kilometers from the transmitter and such lesser distances No terrain roughness correction need be applied when all field strength values of interest are predicted to occur 10 kilometers or less from the transmitting antenna h Profile segments prepared for terrain roughness factor determinations are to be plotted in rectangular coordinates with no less than 50 points evenly spaced within the segment using data obtained from topographic maps with contour intervals of approximately 15 meters 50 feet or less if available i The field strength charts 73 333 Figs 1 1a were developed assuming a terrain roughness factor of 50 meters which is considered to be representative of average terrain in the United States Where the roughness factor for a particular propagation path is found to depart appreciably from this value a terrain roughness correction ΔF should be applied to field strength values along this path as predicted with the use of these charts The magnitude and sign of this correction for any value of Δh may be determined from a chart included in 73 333 as Figure 5 j Alternatively the terrain roughness correction may be computed using the following formula ΔF 1 9 0 03 Δh 1 f 300 Where ΔF terrain roughness correction in dB Δk terrain roughness factor in meters f | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
frequency of signal in MHz MHz Secs 4 5 303 48 Stat as amended 1066 1068 1082 47 U S C 154 155 303 28 FR 13623 Dec 14 1963 as amended at 40 FR 27678 July 1 1975 48 FR 29507 June 27 1983 52 FR 11655 Apr 10 1987 52 FR 37789 Oct 9 1987 57 FR 48333 Oct 23 1992 63 FR 33877 June 22 1998 Effective Date Note At 42 FR 25736 May 19 1977 the effective date of 73 313 paragraphs i and j was stayed indefinitely 73 314 Field strength measurements a Except as provided for in 73 209 FM broadcast stations shall not be protected from any type of interference or propagation effect Persons desiring to submit testimony evidence or data to the Commission for the purpose of showing that the technical standards contained in this subpart do not properly reflect the levels of any given type of interference or propagation effect may do so only in appropriate rule making proceedings concerning the amendment of such technical standards Persons making field strength measurements for formal submission to the Commission in rule making proceedings or making such measurements upon the request of the Commission shall follow the procedure for making and reporting such measurements outlined in paragraph b of this section In instances where a showing of the measured level of a signal prevailing over a specific community is appropriate the procedure for making and reporting field strength measurements for this purpose is set forth in paragraph c of this section b Collection of field strength data for propagation analysis 47 CFR 73 314 b enhanced display page 140 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 314 b 1 Radio Broadcast Services 1 Preparation | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
for measurements i On large scale topographic maps eight or more radials are drawn from the transmitter location to the maximum distance at which measurements are to be made with the angles included between adjacent radials of approximately equal size Radials should be oriented so as to traverse representative types of terrain The specific number of radials and their orientation should be such as to accomplish this objective ii Each radial is marked at a point exactly 16 kilometers from the transmitter and at greater distances at successive 3 kilometer intervals Where measurements are to be conducted over extremely rugged terrain shorter intervals may be used but all such intervals must be of equal length Accessible roads intersecting each radial as nearly as possible at each 3 kilometer marker are selected These intersections are the points on the radial at which measurements are to be made and are referred to subsequently as measuring locations The elevation of each measuring location should approach the elevation at the corresponding 3 kilometer marker as nearly as possible 2 Measurement procedure All measurements must be made utilizing a receiving antenna designed for reception of the horizontally polarized signal component elevated 9 meters above the roadbed At each measuring location the following procedure must be used i The instrument calibration is checked ii The antenna is elevated to a height of 9 meters iii The receiving antenna is rotated to determine if the strongest signal is arriving from the direction of the transmitter iv The antenna is oriented so that the sector of its response pattern over which maximum gain is realized is in the direction of the transmitter v A mobile run of at least 30 meters is made that is centered on the intersection of the radial and the road and the measured | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
field strength is continuously recorded on a chart recorder over the length of the run vi The actual measuring location is marked exactly on the topographic map and a written record keyed to the specific location is made of all factors which may affect the recorded field such as topography height and types of vegetation buildings obstacles weather and other local features vii If during the test conducted as described in paragraph b 2 iii of this section the strongest signal is found to come from a direction other than from the transmitter after the mobile run prescribed in paragraph b 2 v of this section is concluded additional measurements must be made in a cluster of at least five fixed points At each such point the field strengths with the antenna oriented toward the transmitter and with the antenna oriented so as to receive the strongest field are measured and recorded Generally all points should be within 60 meters of the center point of the mobile run viii If overhead obstacles preclude a mobile run of at least 30 meters a cluster of five spot measurements may be made in lieu of this run The first measurement in the cluster is identified Generally the locations for other measurements must be within 60 meters of the location of the first 47 CFR 73 314 b 2 viii enhanced display page 141 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 314 b 3 Radio Broadcast Services 3 Method of reporting measurements A report of measurements to the Commission shall be submitted in affidavit form in triplicate and should contain the following information i Tables of field strength measurements which for each measuring location set forth the following data A Distance from the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
transmitting antenna B Ground elevation at measuring location C Date time of day and weather D Median field in dBu for 0 dBk for mobile run or for cluster as well as maximum and minimum measured field strengths E Notes describing each measuring location ii U S Geological Survey topographic maps on which is shown the exact location at which each measurement was made The original plots shall be made on maps of the largest available scale Copies may be reduced in size for convenient submission to the Commission but not to the extent that important detail is lost The original maps shall be made available if requested If a large number of maps is involved an index map should be submitted iii All information necessary to determine the pertinent characteristics of the transmitting installation including frequency geographical coordinates of antenna site rated and actual power output of transmitter measured transmission line loss antenna power gain height of antenna above ground above mean sea level and above average terrain The effective radiated power should be computed and horizontal and vertical plane patterns of the transmitting antenna should be submitted iv A list of calibrated equipment used in the field strength survey which for each instrument specifies its manufacturer type serial number and rated accuracy and the date of its most recent calibration by the manufacturer or by a laboratory Complete details of any instrument not of standard manufacture shall be submitted v A detailed description of the calibration of the measuring equipment including field strength meters measuring antenna and connecting cable vi Terrain profiles in each direction in which measurements were made drawn on curved earth paper for equivalent 4 3 earth radius of the largest available scale c Collection of field strength data to determine FM broadcast service in | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
specific communities 1 Preparation for measurement i The population P of the community and its suburbs if any is determined by reference to an appropriate source e g the 1970 U S Census tables of population of cities and urbanized areas ii The number of locations at which measurements are to be made shall be at least 15 and shall be approximately equal to 0 1 P 1 2 if this product is a number greater than 15 47 CFR 73 314 c 1 ii enhanced display page 142 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 314 c 1 iii Radio Broadcast Services iii A rectangular grid of such size and shape as to encompass the boundaries of the community is drawn on an accurate map of the community The number of line intersections on the grid included within the boundaries of the community shall be at least equal to the required number of measuring locations The position of each intersection on the community map determines the location at which a measurement shall be made 2 Measurement procedure All measurements must be made using a receiving antenna designed for reception of the horizontally polarized signal component elevated 9 meters above ground level i Each measuring location shall be chosen as close as feasible to a point indicated on the map as previously prepared and at as nearly the same elevation as that point as possible ii At each measuring location after equipment calibration and elevation of the antenna a check is made to determine whether the strongest signal arrives from a direction other than from the transmitter iii At 20 percent or more of the measuring locations mobile runs as described in paragraph b 2 of this section shall be | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
made with no less than three such mobile runs in any case The points at which mobile measurements are made shall be well separated Spot measurements may be made at other measuring points iv Each actual measuring location is marked exactly on the map of the community and suitably keyed A written record shall be maintained describing for each location factors which may affect the recorded field such as the approximate time of measurement weather topography overhead wiring heights and types of vegetation buildings and other structures The orientation with respect to the measuring location shall be indicated of objects of such shape and size as to be capable of causing shadows or reflections If the strongest signal received was found to arrive from a direction other than that of the transmitter this fact shall be recorded 3 Method of reporting measurements A report of measurements to the Commission shall be submitted in affidavit form in triplicate and should contain the following information i A map of the community showing each actual measuring location specifically identifying the points at which mobile runs were made ii A table keyed to the above map showing the field strength at each measuring point reduced to dBu for the actual effective radiated power of the station Weather date and time of each measurement shall be indicated iii Notes describing each measuring location iv A topographic map of the largest available scale on which are marked the community and the transmitter site of the station whose signals have been measured which includes all areas on or near the direct path of signal propagation v Computations of the mean and standard deviation of all measured field strengths or a graph on which the distribution of measured field strength values is plotted vi A list of calibrated | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
equipment used for the measurements which for each instrument specifies its manufacturer type serial number and rated accuracy and the date of its most recent calibration by the manufacturer or by a laboratory Complete details of any instrument not of standard manufacture shall be submitted 47 CFR 73 314 c 3 vi enhanced display page 143 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 314 c 3 vii Radio Broadcast Services vii A detailed description of the procedure employed in the calibration of the measuring equipment including field strength meters measuring antenna and connecting cable 40 FR 27682 July 1 1975 40 FR 28802 July 9 1975 as amended at 48 FR 29508 June 27 1983 73 315 FM transmitter location a The transmitter location shall be chosen so that on the basis of the effective radiated power and antenna height above average terrain employed a minimum field strength of 70 dB above one uV m dBu or 3 16 mV m will be provided over the entire principal community to be served b The transmitter location should be chosen to maximize coverage to the city of license while minimizing interference This is normally accomplished by locating in the least populated area available while maintaining the provisions of paragraph a of this section In general the transmitting antenna of a station should be located in the most sparsely populated area available at the highest elevation available The location of the antenna should be so chosen that line of sight can be obtained from the antenna over the principle city or cities to be served in no event should there be a major obstruction in this path c The transmitting location should be selected so that the 1 mV m contour encompasses | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
the urban population within the area to be served It is recognized that topography shape of the desired service area and population distribution may make the choice of a transmitter location difficult In such cases consideration may be given to the use of a directional antenna system although it is generally preferable to choose a site where a nondirectional antenna may be employed d In cases of questionable antenna locations it is desirable to conduct propagation tests to indicate the field strength expected in the principal city or cities to be served and in other areas particularly where severe shadow problems may be expected In considering applications proposing the use of such locations the Commission may require site tests to be made Such tests should include measurements made in accordance with the measurement procedures described in 73 314 and full data thereon shall be supplied to the Commission The test transmitter should employ an antenna having a height as close as possible to the proposed antenna height using a balloon or other support if necessary and feasible Information concerning the authorization of site tests may be obtained from the Commission upon request e Cognizance must of course be taken regarding the possible hazard of the proposed antenna structure to aviation and the proximity of the proposed site to airports and airways Procedures and standards with respect to the Commission s consideration of proposed antenna structures which will serve as a guide to persons intending to apply for radio station licenses are contained in Part 17 of this chapter Construction Marking and Lighting of Antenna Structures 28 FR 13623 Dec 14 1963 as amended at 41 FR 22943 June 8 1976 49 FR 38131 Sept 27 1984 49 FR 45146 Nov 15 1984 51 FR 9965 Mar 24 1986 52 FR | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
10570 Apr 2 1987 65 FR 79778 Dec 20 2000 73 316 FM antenna systems a It shall be standard to employ horizontal polarization however circular or elliptical polarization may be employed if desired Clockwise or counterclockwise rotation may be used The supplemental vertically polarized effective radiated power required for circular or elliptical polarization shall in no event exceed the effective radiated power authorized 47 CFR 73 316 a enhanced display page 144 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 316 b Radio Broadcast Services b Directional antennas A directional antenna is an antenna that is designed or altered for the purpose of obtaining a non circular radiation pattern 1 Applications for the use of directional antennas that propose a ratio of maximum to minimum radiation in the horizontal plane of more than 15 dB will not be accepted 2 Directional antennas used to protect short spaced stations pursuant to 73 213 or 73 215 of the rules that have a radiation pattern which varies more than 2 dB per 10 degrees of azimuth will not be authorized c Applications for directional antennas 1 Applications for construction permit proposing the use of directional antenna systems must include a tabulation of the composite antenna pattern for the proposed directional antenna A value of 1 0 must be used to correspond to the direction of maximum radiation The pattern must be tabulated such that 0 corresponds to the direction of maximum radiation or alternatively in the case of an asymmetrical antenna pattern the pattern must be tabulated such that 0 corresponds to the actual azimuth with respect to true North In the case of a composite antenna composed of two or more individual antennas the pattern required is that for the composite | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
antenna not the patterns for each of the individual antennas Applications must include valuations tabulated at intervals of not greater than ten 10 degrees In addition tabulated values of all maximas and minimas with their corresponding azimuths must be submitted 2 Applications for license upon completion of antenna construction must include the following i A complete description of the antenna system including the manufacturer and model number of the directional antenna It is not sufficient to label the antenna with only a generic term such as dipole In the case of individually designed antennas with no model number or in the case of a composite antenna composed of two or more individual antennas the antenna must be described as a custom or composite antenna as appropriate A full description of the design of the antenna must also be submitted ii A plot of the composite pattern of the directional antenna A value of 1 0 must be used to correspond to the direction of maximum radiation The plot of the pattern must be oriented such that 0 corresponds to the direction of maximum radiation or alternatively in the case of an asymmetrical antenna pattern the plot must be oriented such that 0 corresponds to the actual azimuth with respect to true North The horizontal plane pattern must be plotted to the largest scale possible on unglazed letter size polar coordinate paper main engraving approximately 18 cm 25 cm 7 inches 10 inches using only scale divisions and subdivisions of 1 2 2 5 or 5 times 10 nth Values of field strength less than 10 of the maximum field strength plotted on that pattern must be shown on an enlarged scale In the case of a composite antenna composed of two or more individual antennas the composite antenna pattern should | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
be provided and not the pattern for each of the individual antennas iii A tabulation of the measured or computer modeled relative field pattern required in paragraph c 1 of this section The tabulation must use the same zero degree reference as the plotted pattern and must contain values for at least every 10 degrees Sufficient vertical patterns to indicate clearly the radiation characteristics of the antenna above and below the horizontal plane Complete information and patterns must be provided for angles of 10 deg from the horizontal plane and sufficient additional information must be included on that portion of the pattern lying between 10 deg and the zenith and 10 deg and the nadir to conclusively demonstrate the absence of undesirable lobes in these areas The vertical plane pattern must 47 CFR 73 316 c 2 iii enhanced display page 145 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 316 c 2 iv Radio Broadcast Services be plotted on rectangular coordinate paper with reference to the horizontal plane In the case of a composite antenna composed of two or more individual antennas the composite antenna pattern should be used and not the pattern for each of the individual antennas iv When the relative field pattern is computer modeled as permitted in paragraphs c 2 iii and x of this section and in 73 1690 c 2 the computer model must be generated by the manufacturer of the antenna and must include a statement from the engineer s responsible for designing the antenna performing the modeling and preparing the manufacturer s instructions for installation of the antenna that identifies and describes the software tool s used in the modeling and the procedures applied in using the software It must also include | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
a certification that the software executed normally without generating any error messages or warnings indicating an error in the program inputs Such computer modeling shall include modeling of the antenna mounted on a tower or tower section and the tower or tower section model must include transmission lines ladders conduits appurtenances other antennas and any other installations that may affect the computer modeled directional pattern The first time the directional pattern of a particular model of antenna is verified using a particular modeling software the license applicant must submit to the Commission both the results of the computer modeling and measurements of either a full size or scale model of the antenna or elements thereof demonstrating reasonable correlation between the measurements achieved and the computer model results Once a particular antenna model or series of elements has been verified by any license applicant using a particular modeling software subsequent license applicants using the same antenna model number or elements and using the same modeling software to verify the directional pattern may submit the computer model for the subsequent antenna installation and cross reference the original submission by providing the application file number v A statement that the antenna is mounted on the top of an antenna tower recommended by the antenna manufacturer or is side mounted on a particular type of antenna tower in accordance with specific instructions provided by the antenna manufacturer vi A statement that the directional antenna is not mounted on the top of an antenna tower which includes a top mounted platform larger than the nominal cross sectional area of the tower in the horizontal plane vii A statement that no other antenna of any type is mounted on the same tower level as a directional antenna and that no antenna of any type is mounted | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
within any horizontal or vertical distance specified by the antenna manufacturer as being necessary for proper directional operation viii A statement from an engineer listing such individual engineer s qualifications and certifying that the antenna has been installed pursuant to the manufacturer s instructions ix A statement from a licensed surveyor that the installed antenna is properly oriented x A For a station authorized pursuant to 73 215 or 73 509 a showing that the root mean square RMS of the measured or computer modeled composite antenna pattern encompassing both the horizontally and vertically polarized radiation components in relative field is at least 85 percent of the RMS of the authorized composite directional antenna pattern in relative field The RMS value for a composite antenna pattern specified in relative field values may be determined from the following formula 47 CFR 73 316 c 2 x A enhanced display page 146 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 316 c 2 x B Radio Broadcast Services RMS the square root of relative field value 1 2 relative field value 2 2 last relative field value 2 total number of relative field values B Where the relative field values are taken from at least 36 evenly spaced radials for the entire 360 degrees of azimuth The application for license must also demonstrate that coverage of the community of license by the 70 dBu contour is maintained for stations authorized pursuant to 73 215 on Channels 221 through 300 as required by 73 315 a while noncommercial educational stations operating on Channels 201 through 220 must show that the 60 dBu contour covers at least a portion of the community of license d Applications proposing the use of FM transmitting antennas in the | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
immediate vicinity i e 60 meters or less of other FM or TV broadcast antennas must include a showing as to the expected effect if any of such proximate operation e Where an FM licensee or permittee proposes to mount its antenna on or near an AM tower as defined in 1 30002 the FM licensee or permittee must comply with 1 30003 or 1 30002 depending on whether the antenna is proposed to be mounted on an AM tower 1 30003 or near an AM tower 1 30002 28 FR 13623 Dec 14 1963 as amended at 34 FR 14222 Sept 10 1969 37 FR 25841 Dec 5 1972 43 FR 53738 Nov 17 1978 48 FR 29508 June 27 1983 51 FR 17028 May 8 1986 54 FR 9804 Mar 8 1989 56 FR 57294 Nov 8 1991 62 FR 51058 Sept 30 1997 63 FR 70047 Dec 18 1998 78 FR 66298 Nov 5 2013 87 FR 15343 Mar 18 2022 87 FR 35430 June 10 2022 73 317 FM transmission system requirements a FM broadcast stations employing transmitters authorized after January 1 1960 must maintain the bandwidth occupied by their emissions in accordance with the specification detailed below FM broadcast stations employing transmitters installed or type accepted before January 1 1960 must achieve the highest degree of compliance with these specifications practicable with their existing equipment In either case should harmful interference to other authorized stations occur the licensee shall correct the problem promptly or cease operation b Any emission appearing on a frequency removed from the carrier by between 120 kHz and 240 kHz inclusive must be attenuated at least 25 dB below the level of the unmodulated carrier Compliance with this requirement will be deemed to show the occupied bandwidth to be 240 kHz | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |
or less c Any emission appearing on a frequency removed from the carrier by more than 240 kHz and up to and including 600 kHz must be attenuated at least 35 dB below the level of the unmodulated carrier d Any emission appearing on a frequency removed from the carrier by more than 600 kHz must be attenuated at least 43 10 Log10 Power in watts dB below the level of the unmodulated carrier or 80 dB whichever is the lesser attenuation e Preemphasis shall not be greater than the impedance frequency characteristics of a series inductance resistance network having a time constant of 75 microseconds See upper curve of Figure 2 of 73 333 51 FR 17028 May 8 1986 47 CFR 73 317 e enhanced display page 147 of 580 47 CFR Part 73 up to date as of 2 20 2024 47 CFR 73 318 Radio Broadcast Services 73 318 FM blanketing interference Areas adjacent to the transmitting antenna that receive a signal with a strength of 115 dBu 562 mV m or greater will be assumed to be blanketed In determining the blanketed area the 115 dBu contour is determined by calculating the inverse distance field using the effective radiated power of the maximum radiated lobe of the antenna without considering its vertical radiation pattern or height For directional antennas the effective radiated power in the pertinent bearing shall be used a The distance to the 115 dBu contour is determined using the following equation D in kilometers 0 394 P D in miles 0 245 P Where P is the maximum effective radiated power ERP measured in kilowatts of the maximum radiated lobe b After January 1 1985 permittees or licensees who either 1 commence program tests or 2 replace their antennas or 3 request | corpus_data/corpus_txt/47-CFR-Part-73-_up-to-date-as-of-2-20-2024_.txt |