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Old July 19th 06, 01:31 AM posted to rec.aviation.piloting
Roger (K8RI)[_1_]
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Posts: 3
Default FM radio interference from planes

On Tue, 18 Jul 2006 14:19:48 -0700, "Peter Duniho"
wrote:

"Roger (K8RI)" wrote in message
.. .
If it is a part 15 device (very low power no license required. This
includes the wireless mikes, remote speakers, remote weather stations,
WiFi computer networks, and a whole bunch of other *stuff*) the
*required* sticker on the back says two things. He *may not* cause
any interference and has to accept any he receives.


What you (and the other responders) are failing to understand is that the
device in question is a TRANSMITTER. As such, it may very well interfere
with any other device, and such interference would be perfectly legal (as


No it is not. The FCC is very adamant about the interference
interpretation.

long as the transmitter is operating within its legal requirements, a safe


That is the point! The "transmitting" device may not cause (is not
allowed to cause) interference even when it when it is operated fully
with in compliance to part 15. A number of companies are finding that
out the expensive way at present.

assumption given the "off-the-shelf device intended for the use in which
he's applying it" qualification that started this subthread).

You cannot get a complete education on FCC regulations from a little sticker
found on the back of Part 15 devices.


For part 15 devices that little sticker says it all.
The only thing you shouldn't have to worry about interfering with
would be another part 15 device.

As this one is operating in the FM broadcast band even if operated
within the limitations and his neighbors hear it and complain he'd
have to shut it down.

However the original post was not about the transmitter at all, but
him hearing aircraft radios through his system. That could be
intermod/front end overload, or images. As he's listening around 108
and aircraft are roughly 130 that gives a difference of 22 MHz which
shouldn't create an image problem unless one of the IFs runs in the 22
or 44 MHz range. So, I'd guess it's probably front end overload with
intermod.

I occasionally hear aircraft that would be transmitting on 126.45, or
118.45 on 147.00 MHz. However I'm directly under the GPS/RNAV 6 app
into Midland Barstow. Which means they are quite close to my antenna.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Pete

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com