[BC] 9th FM harmonic causing interference

[Kevin C. Kidd CSRE/AMD]

Although not harmonically related, I had an FAA tech call to tell me
that I had to immediately shut down the #2 station in the market due to
the interference that we were causing to a main aircraft channel at
Huntsville (AL) International Airport.  He wasn't particularly polite.

The stations audio was clearly audible on all aircraft and tower radios
within a couple miles of the airport and was causing delays in "ground
procedures".

I happened to be in the area AND had my spectrum analyzer.  Checking the
TX output showed ZERO signal on the freq in question.  I was just about
to shut the TX down when the tech called back telling me to hold off for
a few minutes.

He called back a few minutes later to tell me that he found an aircraft
radio keyed in the general aviation area of the airport.  It seems that
a pilot had his headset wired to listen to the station in one earpiece,
had folded the mic back into the headset, pitched the headset down
between the seats which accidentally hit and locked down a mic button.
Hence, my client was being clearly heard on the locked down transmitter.

He was much more polite on the last call.

On 2/18/2010 7:02 AM, Mike McCarthy wrote:
> I had this very same issue occur to a co-located cell site 200ft. down
> from the main 7 bay FM. It was Nextel.
> 

-- 
Kevin C. Kidd, CSRE/AMD
http://www.kkbc.com
http://www.amgroundsystems.com
Local:        931-766-2999