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73.827: Difference between revisions
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Part 73, Subpart G, Section 73.827 is a complex rule that addresses interference by LPFM stations to the "input" channels of FM translators. | [[Part 73]], [[Subpart G]], Section 73.827 is a complex rule that addresses interference by LPFM stations to the "input" channels of FM translators. | ||
== Interference to the input of an FM translator == | == Interference to the input of an FM translator == | ||
FM translator stations are intended to rebroadcast the signals of a full-service FM station to another area. Some translators are used to rebroadcast the signal of an AM radio station and others are used to rebroadcast the HD subchannels (HD2, HD3 or HD4) of a full-service FM stations allowing these HD subchannels to be heard on an analog FM radio that does not include HD Radio functionality. | FM translator stations are intended to rebroadcast the signals of a full-service FM station to another area. Some translators are used to rebroadcast the signal of an AM radio station and others are used to rebroadcast the HD subchannels (HD2, HD3 or HD4) of a full-service FM stations allowing these HD subchannels to be heard on an analog FM radio that does not include [[HD Radio]] functionality. | ||
Many FM translators are required to receive the full-service FM station directly over the air or through another FM translator over the air. The frequency that the FM translator receives their source signal is referred to as their "input channel". | Many FM translators are required to receive the full-service FM station directly over the air or through another FM translator over the air. The frequency that the FM translator receives their source signal is referred to as their "input channel". | ||
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== Third-adjacent input channel interference == | == Third-adjacent input channel interference == | ||
Section 6 of the Local Community Radio Act of 2010 requires that the FCC establishes standards to address interference to FM translator inputs by LPFM stations operating on the third-adjacent channel of the input channel that the FM translator is monitoring. The rule states that an LPFM station will not be authorized if on a third-adjacent channel, there is an input channel for an FM translator and the LPFM station is located either within 2 kilometers (1.24 miles) of the FM translator in any direction or within 10 kilometers (6.21 miles) of a translator when the LPFM station is located in the "path" between the FM translator and the station it is monitoring. This is done by determining the bearing (direction) of the path from the FM translator to the station it is monitoring and then protecting the radii within 30 degrees in either direction. An LPFM station proposing operation in this "potential interference area" may need to be prepared to make a technical study that shows that no interference takes place. The rule provides three different technical methods to demonstrate a lack of interference. | Section 6 of the [[Local Community Radio Act of 2010]] (LCRA) requires that the FCC establishes standards to address interference to FM translator inputs by LPFM stations operating on the third-adjacent channel of the input channel that the FM translator is monitoring. The rule states that an LPFM station will not be authorized if on a third-adjacent channel, there is an input channel for an FM translator and the LPFM station is located either within 2 kilometers (1.24 miles) of the FM translator in any direction or within 10 kilometers (6.21 miles) of a translator when the LPFM station is located in the "path" between the FM translator and the station it is monitoring. This is done by determining the bearing (direction) of the path from the FM translator to the station it is monitoring and then protecting the radii within 30 degrees in either direction. An LPFM station proposing operation in this "potential interference area" may need to be prepared to make a technical study that shows that no interference takes place. The rule provides three different technical methods to demonstrate a lack of interference. | ||
== Other input channel interference == | == Other input channel interference == | ||
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(2) Complies with the minimum LPFM/FM translator distance separation calculated in accordance with the following formula: d<sub>u</sub> = 133.5 antilog [(P<sub>eu</sub> + G<sub>ru</sub> − G<sub>rd</sub> − E<sub>d</sub>)/20], where d<sub>u</sub> = the minimum allowed separation in km, P<sub>eu</sub> = LPFM ERP in dBW, G<sub>ru</sub> = gain (dBd) of the FM translator receive antenna in the direction of the LPFM site, G<sub>rd</sub> = gain (dBd) of the FM translator receive antenna in the direction of the primary station site, E<sub>d</sub> = predicted field strength (dBu) of the primary station at the translator site, or | (2) Complies with the minimum LPFM/FM translator distance separation calculated in accordance with the following formula: d<sub>u</sub> = 133.5 antilog [(P<sub>eu</sub> + G<sub>ru</sub> − G<sub>rd</sub> − E<sub>d</sub>)/20], where d<sub>u</sub> = the minimum allowed separation in km, P<sub>eu</sub> = LPFM ERP in dBW, G<sub>ru</sub> = gain (dBd) of the FM translator receive antenna in the direction of the LPFM site, G<sub>rd</sub> = gain (dBd) of the FM translator receive antenna in the direction of the primary station site, E<sub>d</sub> = predicted field strength (dBu) of the primary station at the translator site, or | ||
(3) Reaches an agreement with the licensee of the FM translator regarding an alternative technical solution. | (3) Reaches an agreement with the licensee of the FM translator regarding an alternative technical solution.<blockquote>Note to paragraph (a): | ||
LPFM applicants may assume that an FM translator station's receive and transmit antennas are collocated.</blockquote>(b) An authorized LPFM station will not be permitted to continue to operate if an FM translator or FM booster station demonstrates that the LPFM station is causing actual interference to the FM translator or FM booster station's input signal, provided that the same input signal was in use or proposed in an application filed with the Commission prior to the release of the public notice announcing the dates for an LPFM application filing window and has been continuously in use or proposed since that time. | |||
LPFM applicants may assume that an FM translator station's receive and transmit antennas are collocated. | |||
(b) An authorized LPFM station will not be permitted to continue to operate if an FM translator or FM booster station demonstrates that the LPFM station is causing actual interference to the FM translator or FM booster station's input signal, provided that the same input signal was in use or proposed in an application filed with the Commission prior to the release of the public notice announcing the dates for an LPFM application filing window and has been continuously in use or proposed since that time. | |||
(c) Complaints of actual interference by an LPFM station subject to paragraph (b) of this section must be served on the LPFM licensee and the Federal Communications Commission, Attention: Audio Division, Media Bureau. The LPFM station must suspend operations upon the receipt of such complaint unless the interference has been resolved to the satisfaction of the complainant on the basis of suitable techniques. Short test transmissions may be made during the period of suspended operations to check the efficacy of remedial measures. An LPFM station may only resume full operation at the direction of the Federal Communications Commission. If the Commission determines that the complainant has refused to permit the LPFM station to apply remedial techniques that demonstrably will eliminate the interference without impairment of the original reception, the licensee of the LPFM station is absolved of further responsibility for the complaint. | (c) Complaints of actual interference by an LPFM station subject to paragraph (b) of this section must be served on the LPFM licensee and the Federal Communications Commission, Attention: Audio Division, Media Bureau. The LPFM station must suspend operations upon the receipt of such complaint unless the interference has been resolved to the satisfaction of the complainant on the basis of suitable techniques. Short test transmissions may be made during the period of suspended operations to check the efficacy of remedial measures. An LPFM station may only resume full operation at the direction of the Federal Communications Commission. If the Commission determines that the complainant has refused to permit the LPFM station to apply remedial techniques that demonstrably will eliminate the interference without impairment of the original reception, the licensee of the LPFM station is absolved of further responsibility for the complaint. | ||