I'm sure this is a really obvious question and I'm also sure I'm
showing my inexperience by even asking, but hopefully I will be spared
criticism, however appropriate it may be.

Here (in the SF Bay Area) I consistently hear what I can only describe
as "satellite noise" around 4Mhz. You know that sort of high-pitched
squeeling noise they play during movies when they're showing a
satellite in orbit? Or when they show a tracking screen with those
sinusoidal waves? Yeah, that sound. I didn't think satellites messed
around with such low frequencies, but maybe I am wrong? Does anyone
know what this might be?

I've just gotten into shortwave radio and while I like listening to all
of the chatter, I am particularly fond of the noises that I am picking
up. There just seem to be so many types. I wish I knew which ones are
nonesense atmospheric/mechanical noise and which are meaningful. I hear
a lot of pulses or tones at regular intervals (and that are not the UTC
time broadcast). I wonder what these are.

Hmm. . .

Selwyn-Lloyd