Radium hath wroth:

AFAIK, the main issue with AM is that it is much more vulnerable to
magnetic disruptions than FM.

Wrong. Take a magnet, any magnet. Wave it around your AM or FM
radio. Hear anything different? You won't. Therefore, forget about
magnetic disturbances. The main issue with AM is susceptibility to
pulsed noise, as found in motors, fans, auto engines, and computahs.
FM doesn't have as bad a problem because the limiter in the receiver
clips everything to the same level, thus reducing the effect.

That is why when you are listening to
the AM radio at home and someone turns on the microwave-oven, you here
those odd sounds on the receiver.

No. Microwave ovens operate at 2400Mhz. AM broadcast operates at
1MHz. No way there's going to be any interference there. However,
the microwave oven may have a fan or CPU that runs the display, that
belches garbage at 1MHz. I just tried mine and there's a tiny bit of
buzz coming from the display section when I shove an AM radio right up
to the display. If that's what you're hearing, I would test it with a
different microwave oven. If only yours has the problem, I suggest
you consider a replacement.

Also, if there is a solar prominence you can hear the resulting
magnetic disruptions on an AM radio receiver. They sound scary and
enjoyable at the same time.

You can also hear lightning storms. In the US, most of those are in
the south east of the country. Nothing like interference from 3000
miles away. Lightning detectors operate in the 25-50KHz region.
Incidentally, there are about 8 million lightning hits per day, which
is why the noise sounds almost continuous.

(chomp...)

Sorry, my time is up. Please insert $0.25 for the next 3 minutes.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558