Section 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. |
1 After 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