FCC Seizes Radio Equipment
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.
Lake Wobegone, NH
Sent from my iPhone
Big freekin deal!
On May 27, 2011, at 7:01 AM, Sid Schweiger <email@example.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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