RF interference issue again (esp. for E Drucker and Jim Weir and other RF wizards)

On 4-Nov-2003, (Snowbird) wrote:

Elliot, given what we did, is there a way to pinpoint what
signals might be the source of the problem?

That would be pretty difficult because of the huge number of different
combinations of out-of-band signals that could cause the intermodulation
interference.



Given the lat-long, is there a way to find out what antennas
are located there?

Generally, the locations of all commercial broadcast sites in the US are
public domain information available from the FCC. Some or all of this info
is probably available on-line. Unfortunately, I am not particularly
knowledgeable when it comes to tools that might be available for searching
the appropriate FCC data bases.


Is there something which might be a problem in our radios,
which could be fixed?

The fact that three different radios that you tested were similarly affected
suggests that the problem is not a specific malfunction. A "solution" would
most logically involve placing a bandpass filter between each of your com
antennas and the corresponding transceiver. I do not have knowledge of such
filters being commercially available, but others might know of such
products.


At this point the question is whether the interference poses a threat to
safety or merely an annoyance. When the interference "breaks squelch
while
you are tuned to the TRACON freq are you still able to hear the
controller
when he/she transmits?

On one installed radio and the handheld, yes. On the other installed
radio, the controller becomes very faint against a background of
continued noise.

In that case I certainly think that you should bring the problem to the
attention of the FAA.

OK, I was thinking about this. Can you suggest which person in the
FSDO I'd ask for?

I'm no expert about FSDO organization, but I would start with the office of
the Facilities Director.

--
-Elliott Drucker