OK, this is no longer an isolated incident. It's 5:00 PM, and noise is off the charts again... luckily, after the incident a couple days ago, i made all local control not send links, so at least those work.
however, i can no longer blame this on the snow (in the 50's today). it looks more and more like it must be from outside the house, although I can't prove it. The only thing I know is that nothing is on in my house that is not normally on. At this rate, if this happens every other day, I'll have to declare UPB unusable soon. Somebody who cares about whether or not I use UPB, please help.
Who's devices are they - SAI? If so call Brad Cone at 760-431-2100. They are very good at support and I'm sure will do whatever in their power to at least help diagnose it.
Also, as a test, are you friendly with one of your neighbors? If so, take a laptop and PIM and an appliance or lamp module over to their house and check it out. See if they have noise as well. If so, try another neighbor. If all the neighbors have the same noise then it is a good chance it is coming from outside. I have heard once that a bad transformer put a ton of noise on the line. If you can show there is all this noise in several houses perhaps you can get the local utility company to do some tests or find the faulty component. I don't know the size of your install or your local area but I know this was done before. If you know the layout of your power grid and who is on what transformer it would be ideal if you can try the above in someone's house on a different transformer also.
Also, have any of your neighbors plugged in any major electrical equipment outside their house?
If you do not have a problem in a neighbors house on the same transformer then you need to look harder in your place for something that might have gone bad. I know its not fun, but there are always gotchas with PLC. I went thru the same thing with x10 and could never get it to work, even on a single circuit with nothing else there.
Do you have any CFL's in your house, either old or new? You may want to remove those to test, or kill the breaker they are on.
There is no guarantee anything else beside hardwire will work any better or have issues either, so if you have an investment already I would certainly give it everything I had before getting frustrated and switching it out.
Hang in there, usually these things can be worked out with some persistence.