Translators aren’t just for filling in FM signal coverage gaps anymore.
They have become a more important part of radio owners’ spectrum strategy toolkit. Many commercial and noncommercial radio operators — both AM and FM — are using FM translators in ways previously unimagined, not only supplementing local signal coverage but leveraging them to gain a more lucrative footprint on the FM dial for content that originally airs on AM stations or FM HD2/HD3 channels.
Demand for translators also is increasing as broadcasters realize they effectively can create additional radio stations in markets by location-hopping and moving towards more heavily populated areas, according to several technical radio observers.
An FM translator retransmits the signal of an AM or FM radio station without significantly altering characteristics of the original other than its frequency and amplitude. FM translators historically have been used to fill in coverage where terrain blockage was an issue.
There were 6,141 licensed FM translators and boosters as of March 2011, according to the FCC. That compares to 3,897 in 2005 and 3,243 in 2000, according to commission data. FM boosters essentially are translators that operate on the same frequency as the primary station. The FCC doesn’t distinguish between FM translators and boosters in its database.
Approximately 500 FM translators simulcast AM broadcast stations. That’s a measure of the success of a rule change, adopted just two summers ago, allowing AMs to use existing FM translators in certain circumstances.
Observers say radio’s evolving translator strategies simply take advantage of current translator rules. For instance, a broadcaster can add a fill-in translator with power up to 250 watts regardless of antenna height as long as it does not exceed the protected contour of the associated primary station.
Interestingly, the 60 dBu of a 250 watt fill-in translator at 2,000 feet height above average terrain presents the same coverage area as a Class B or C2 FM station, thus “creating fairly high-power entities,” said Doug Vernier, president of broadcast engineering consulting firm V-Soft Communications.