Running dogg, when you say "N. California location," where is that?
Near SF?

I am near SF (East Bay) and I get scores of seemingly random noises
across 5 - 10 MHz. 49m is especially bad for weird unidentifiable QRM.
Some of it sweeps (moves up and down the frequency scale), or changes
pitch while maintaiing a single RF.

I get intermod junk from local 50kW MW stations. Bad in wet weather
when the ground improves.

I also get screwy stuff that just comes on and off. Some of it fades
in and out like the HF signals, so some of it may be far away.

Also get the usual streetlight junk, too - that's fixable.

Bruce Jensen