Author Topic: Legality of broadcating on 87.9 MHz  (Read 259 times)

jordan

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Legality of broadcating on 87.9 MHz
« on: October 18, 2017, 2248 UTC »
I've been reading some FCC notices of violations, fines, etc. that they've issued to people. I noticed that some had been busted for using 87.9 MHz, and that they exceeded the limit of 100mV/meter as measured 3 meters from the antenna.  On the standard FM band (88-108 MHz), they have a limit of 250 microvolts per meter measured 3m from antenna.  For comparision, 100mV per meter is a lot more than 250 microvolts, which equates to 100,000 microvolts.  Does anyone know what power wattage this would equate to?

In laymen's terms, it sounds like we're allowed to use a lot more power on 87.9 than we are the rest of the FM band.  Could someone elaborate on this?

redhat

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Re: Legality of broadcating on 87.9 MHz
« Reply #1 on: October 19, 2017, 0113 UTC »
The letter of the law is left open to interpretation and as usual quite vague.  This is usually done to allow inspectors greater lattitude in the field. Under the intentional radiator category, the law states 100uV/M below 88 MHz, but 150uV/M above. 

https://www.law.cornell.edu/cfr/text/47/15.209

Yet in this part, its states 250uV/M

https://www.law.cornell.edu/cfr/text/47/15.239

Who knows....

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