§ 78.103   Emissions and emission limitations.

   (a) A CARS station may be authorized to employ any type of emission, for
   which there are technical standards incorporated in Subpart D of this part,
   suitable for the simultaneous transmission of visual and aural television
   signals.

   (b) Any emission appearing on a frequency outside of the channel authorized
   for a transmitter shall be attenuated below the power of the emission in
   accordance with the following schedule:

   (1) For stations using FM or double sideband AM transmission:

   (i)  On any frequency above the upper channel limit or below the lower
   channel limit by between zero and 50 percent of the authorized channel
   width: At least 25 decibels below the mean power of the emission;

   (ii) On any frequency above the upper channel limit or below the lower
   channel  limit  by  more  than 50 percent and up to 150 percent of the
   authorized channel width: At least 35 decibels below the mean power of the
   emission; and

   (iii) On any frequency above the upper channel limit or below the lower
   channel limit by more than 150 percent of the authorized channel width: At
   least 43 + 10 log10 (power in watts) decibels below the mean power of the
   emission.

   (2) For CARS stations using vestigial sideband AM transmission: At least 50
   decibels below the peak power of the emission.

   (c) For operation in the 17.7.7-19.7 GHz band:

   The mean power of any emission shall be attenuated below the mean output
   power of the transmitter in accordance with the following schedule:

   (1) When using frequency modulation:

   (i) On any frequency removed from the assigned (center) frequency by more
   than 50% up to and including 100% of the authorized bandwidth: At least 25
   dB;

   (ii) On any frequency removed from the assigned (center) frequency by more
   than 100% up to and including 250% of the authorized bandwidth: At least 35
   dB;

   (iii) On any frequency removed from the assigned (center) frequency by more
   than 250% of the authorized bandwidth: At least 43 + 10 log 10 (mean output
   power in watts) dB, or 80 dB, whichever is the lesser attenuation.

   (2) When using digital modulation:

   (i) In any 1 MHz band, the center frequency of which is removed from the
   assigned  frequency  by  more than 50% up to and including 250% of the
   authorized bandwidth: As specified by the following equation but in no event
   less than 11 dB.

   A = 11 + 0.4 (P − 50) + 10 log10 B

   where:

   A = Attenuation (in dB) below the mean output power level.

   P = Percent removed from the carrier frequency.

   B = Authorized bandwidth in MHz.

   [Attenuation greater than 56 decibels is not required.]

   (ii) In any 4 kHz band, the center frequency of which is removed from the
   assigned frequency by more than 250% of the authorized bandwidth: At least
   43 = 10 log10 (mean output power in watts) dB, or 80 dB, whichever is the
   lesser attenuation.

   (3) Amplitude Modulation:

   For vestigial sideband AM video: On any frequency removed from the center
   frequency of the authorized band by more than 50%: at least 50 dB below peak
   power of the emission.

   (d) In the event that interference to other stations is caused by emissions
   outside  the  authorized  channel,  the Commission may require greater
   attenuation than that specified in paragraph (b) of this section.

   (e) The maximum bandwidth that will be authorized per frequency assignment
   is set out in the table that follows. Regardless of the maximum authorized
   bandwidth specified for each frequency band, the Commission reserves the
   right to issue a license for less than the maximum bandwidth if it appears
   that a bandwidth less than the maximum would be sufficient to support an
   applicant's intended communications.
   Frequency band (MHz) Maximum authorized band-width (MHz)
   1,990 to 2,110       17 or 18.^1
   6,425 to 6,525       8 or 25.
   6,875 to 7,125       25.
   12,700 to 13,250     25.
   17,700 to 19,700     80.

   ^1After a licensee has been relocated in accordance with § 78.40, the maximum
   authorized bandwidth in the frequency band 2025 to 2010 MHz will be 12
   megahertz.

   [ 37 FR 3292 , Feb. 12, 1972, as amended at  37 FR 15927 , Aug. 8, 1972;  38 FR 16648 , June 25, 1973;  39 FR 26025 , July 16, 1974;  48 FR 50736 , Nov. 3, 1983;
    49 FR 37779 , Sept. 26, 1984;  52 FR 7145 , Mar. 9, 1987;  65 FR 48182 , Aug. 7,
   2000;  68 FR 12776 , Mar. 17, 2003;  68 FR 68253 , Dec. 8, 2003]

   return arrow Back to Top