"Dave" wrote in message
...
Brenda Ann wrote:
"Jim-NN7K" . wrote in message
...
And, another incident- in
Portland, had a Phone line to Eugene, passed KXL (1190KHz?) radio
station- Had enough leakage, that it got into the baseband of our
microwave system!
we wern't using baseband that high, but when FCC inspected our El Paso,
Texas facility, cited us for re-transmitting that signal, on our
microwave system! Take it to the bank-- dumb things happen! Jim NN7K

KXL (5000 watts) is at 750 KHz. KEX (50,000 watts) is at 1190 KHz. If
your system was anywhere near I-205 at Clackamas, then it would not
surprise me that KEX would get into it. Once I was driving by their tower
site and decided to be funny. It was in my 1969 Pontiac wagon. I
commented to my passengers that "I bet I can really get a good signal
from KEX right now.." and punched the button for KEX on my car radio..
which greeted me with total silence! I just happened to punch that button
while in the strongest part of their pattern, and it took out the RF amp
and local oscillator in the radio (damn, that was a good radio, too...)



Desense doesn't do anything to the local oscillator. It is merely a
nearby (still in the same bandpass as the AVC detector) undesired signal
strong enough to make your AVC turn the gain way down.

It wasn't desense. I benched the radio, and the RF amp was shorted (B-E, B-C
and C-E), while the LO lost only the B-E junction. This happened instantly
when I punched the button for KEX on the radio. It wasn't KEX desensing the
radio while listening to the other station (KGW 620 at the time).

Desense occurs around those towers for about half a mile or so, especially
if you're inline with the beam.