(Jay) wrote:

The spectrum analyzer (if you can get one) will answer your inter mod
products question. You might make friends with your local HAM group.
Some of these guys may enjoy the hunt, an airplane ride, and have the
high dollar equipment to do it. But I'm betting that the cause
something simpler than that. The fact that you mentioned that they
were AM broadcasts reminds me of the times I used to get AM radio on
my telephone. In very high fields with amplitude modulation you can
get what's often called "detection by overload". Any non-linear
circuit element in your radio- front end through audio amp have all
kinds of semiconductors which can "detect" and demodulate the AM
broadcast if the signal is powerful enough. In the case of my
telephone, the bridge rectifier that protected the polarity of the
phone was the detector.

I used to be able to turn OFF my car radio and STILL get a loud
"bbBBBRRRRrrrrzzzz" every time the long range radar swept past my car
about 1/4 mile away on US1 in Key West (you could tell which way the
dish was turning in the radome by how long the sweep took).

Talk about "detection by overload"...

Mark Hickey