FCC Seizes Radio Equipment

Larry Weil kc1ih@mac.com
Fri May 27 14:35:01 EDT 2011

If you are thinking of image reception, the image frequency is TWICE the I.F. frequency above or below the tuned frequency, thus 21.4 above or below on a common FM receiver.

Larry Weil
Lake Wobegone, NH

Sent from my iPhone
Big freekin deal!

On May 27, 2011, at 7:01 AM, Sid Schweiger <sid@wrko.com> wrote:

> "The pirate was an FM signal, and last I heard aviation communications are done in AM.  So how did the pirate interfere with air traffic?"
> One theory:  99.7 + 10.7 (the IF commonly used in FM receivers) = 110.4, square in the middle of the aviation band.  Another theory:  Spurious radiations from a cheap transmitter with likely little or no filtering and poor frequency control.  In any case, even if the interfering signal uses a different modulation type, just the presence of the signal is enough to interfere, and when commercial aviation is involved, the FCC doesn't hesitate to act.
> Sid Schweiger
> IT Manager, Entercom New England
> 20 Guest St / 3d Floor
> Brighton MA  02135-2040

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