In two Notices of Violation issued on one day this week, an FCC Field Office cited Low Power FM operators for using transmission systems that, in addition to transmitting signals on their authorized channels, were also emitting signals on other channels that posed the potential for interference with other users on those other frequencies – sometimes not even broadcast frequencies.  In one case, the FCC noted that it was the FAA that reported the interference (the other notice released the same day is available here).

All broadcast transmissions have the potential for these spurious emissions on channels other than the ones for which a station is authorized, especially if a station is near other stations as frequencies can interact to produce these unintended emissions.  When constructing and operating any broadcast station, care should be given to ensure that these off-channel emissions are not of a signal strength beyond that permitted by the FCC rules as interference can occur and the FCC can potentially impose fines.
Continue Reading FCC Notes Violations for Two LPFM Operators for Spurious Emissions – Make Sure that Your Station is Transmitting Only Within Its Assigned Frequency