Jeff Liebermann wrote:
If you're thinking of impulse noise, you're mostly correct. However,
there are plenty of other sources of AM noise available. For example,
the typical VHF aircraft radio requires substantial filtering of the
magneto to avoid hash. Same with any onboard motor. If you've ever
tried to install a TV (VSB is a form of AM) in a vehicle, you'll also
find that ignition and motor noise can be a problem.

Dang it...my memory is slipping. What did Motorola call their noise
filtering circuit on their old low band Motracs. Extenders[tm]? As I recall
it was a simple noise blanker.