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Translators--93.7 FM specifically

W

WarwickRadioFan

Can anyone explain the spacing requirements for FM translators. The new 93.7 translator located at the WSTL transmitter site in East Providence seems way too close to 94.1's transmitter (and even 93.3) for it to meet any spacing requirements. Even if it does not interfere with either station, doesn't it receive objectionable interference from at least one of them?

Also, they seem to be running WSTL's programming with FM quality audio--which suggests that they aren't "translating" a received AM signal, but simply feeding the translator from the air chain.

Maybe someone can shed some light on these issues.
 
I think that the only way for a translator to be second adjacent to a big station is actually if it's close to it, believe it or not.

The translator does not have to be picking up the AM audio over the air, they can supply the audio separately. This is the way it's done with most of the new AM-FM translators.
 
jlehmann said:
I think that the only way for a translator to be second adjacent to a big station is actually if it's close to it, believe it or not.
Click to expand...

Correct. The key here is in the ratio between the signal level of the translator and of the adjacent full-power station at any given location.

At the WSTL site, WSNE's field strength is 93.1 dBu (very, very strong), while WHJY's is 119.0 dBu (fry-the-front-end-off-your-radio strong).

The FCC wants to see no less than a 40 dB ratio between the desired full-power signal and the undesired translator signal...so all W227AN had to demonstrate is that there's nobody living within the 133.1 dBu (40 dB above WSNE) contour of the translator signal. That's easy, since the 133.1 dBu contour of a 30-watt signal extends about 25 feet from the antenna.

Put the translator further out from the second-adjacent high-powered signal and you have a bigger problem, since you're protecting a weaker full-power signal, and thus dealing with a lower signal-strength contour for the translator. Imagine putting the translator out in, say, Warwick, where WSNE might deliver only 65 dBu. Now you've got to prove that there's no population within the 105 dBu contour of the translator - not impossible, but more challenging.

And of course it's still possible for there to be other interference issues. The FCC protects "existing reception" of a full-power station from translator incursion, no matter whether it's within or outside of the full-power station's protected contours. So if WMKK, for instance, wanted to find listeners in the Providence area who are now experiencing interference from W227AN, it would have a case to force the translator to alleviate the interference, or, if that's not possible, to shut down. It's been done in other places...
 
Thanks for the technical explanation...but despite the fact that the translator does fit, I suppose the question is: why put on a signal that accepts so much interference from other stations and is hemmed in by 93.7 from Mass.? Is it the most efficient use of that frequency in that location?
 
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