§  74.861   Technical requirements.

   (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 log10 (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]

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