On 3/19/2011 5:02 AM, m II wrote:

The noise that's been plaguing me for weeks turns out to be the solar
panel battery charger/regulator. It's worse than any dimmer or
fluorescent light I've ever heard. The unit is an Outback 60 amp mppt. I
don't imagine there's an easy way to stop the noise. Night time
miraculously clears things up.

Well, maybe not "easy", but not all that hard either. I'm not sure of
your electronic skill levels (be careful if you try this), but buy a
handful of .001 ufd disc ceramic capacitors and install them on the
appropriate leads and wrap multiple turns of the leads going in to / out
of the regulator box through ferrite cores. If the wires are too big for
that, slip several ferrite beads over the leads. Cheap, can't hurt,
might help.

Another suggestion before you get out the soldering iron: try contacting
the manufacturer; I'm sure you are not the first person to experience
this problem, so why try and re-invent the wheel? They may have a solution.