(a) Transmitter power is the power at the transmitter output terminals and delivered to the antenna, antenna transmission line, or any other impedance-matched, radio frequency load. For the purpose of this subpart, the transmitter power is the carrier power.
(b) Each authorization for a new low power auxiliary station shall require the use of certificated equipment. Such equipment shall be operated in accordance with the emission specifications included in the certification grant and as prescribed in paragraphs (c) through (e) of this section.
(c) Low power auxiliary transmitters not required to operate on specific carrier frequencies shall operate sufficiently within the authorized frequency band edges to insure the emission bandwidth falls entirely within the authorized band.
(d) For low power auxiliary stations operating in the bands other than those allocated for TV broadcasting, the following technical requirements are imposed.
(1) The maximum transmitter power which will be authorized is 1 watt. Licensees may accept the manufacturer's power rating; however, it is the licensee's responsibility to observe specified power limits.
(2) If a low power auxiliary station employs amplitude modulation, modulation shall not exceed 100 percent on positive or negative peaks.
(3) The occupied bandwidth shall not be greater than that necessary for satisfactory transmission and, in any event, an emission appearing on any discrete frequency outside the authorized band shall be attenuated, at least, 43 10 log 10 (mean output power, in watts) dB below the mean output power of the transmitting unit.
(e) For low power auxiliary stations operating in the bands allocated for TV broadcasting, the following technical requirements apply:
(1) The power of the measured unmodulated carrier power at the output of the transmitter power amplifier (antenna input power) may not exceed the following:
(i) 54-72, 76-88, and 174-216 MHz bands—50 mW
(ii) 470-608 and 614-698 MHz bands—250 mW
(2) Transmitters may be either crystal controlled or frequency synthesized.
(3) Any form of modulation may be used. A maximum deviation of ±75 kHz is permitted when frequency modulation is employed.
(4) The frequency tolerance of the transmitter shall be 0.005 percent.
(5) The operating bandwidth shall not exceed 200 kHz.
(6) The mean power of emissions shall be attenuated below the mean output power of the transmitter in accordance with the following schedule:
(i) On any frequency removed from the operating frequency by more than 50 percent up to and including 100 percent of the authorized bandwidth: at least 25 dB;
(ii) On any frequency removed from the operating frequency by more than 100 percent up to and including 250 percent of the authorized bandwidth: at least 35 dB;
(iii) On any frequency removed from the operating frequency by more than 250 percent of the authorized bandwidth: at least 43 10log10 (mean output power in watts) dB.
(f) Unusual transmitting antennas or antenna elevations shall not be used to deliberately extend the range of low power auxiliary stations beyond the limited areas defined in § 74.831.
(g) Low power auxiliary stations shall be operated so that no harmful interference is caused to any other class of station operating in accordance with Commission's rules and regulations and with the Table of Frequency Allocations in part 2 thereof.
(h) In the event a station's emissions outside its authorized frequency band causes harmful interference, the Commission may, at its discretion, require the licensee to take such further steps as may be necessary to eliminate the interference.
(Sec. 5, 48 Stat. 1068; 47 U.S.C. 155)
[43 FR 13576, Mar. 31, 1978, as amended at 52 FR 2535, Jan. 23, 1987; 63 FR 36605, July 7, 1998; 75 FR 3639, Jan. 22, 2010]
Title 47 published on 2012-10-01
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