I've been plagued by S7-S9 noise level on 20M but no problems on the other bands. I checked with John (N9BTM) who who lives only 2 houses up the street from me and he reported only S1-S2 while I was seeing S7. Went back home and ran the Kenwood on battery power - no difference. Turned off the house main breaker and the noise went away. Turned off all the individual breakers, turned the main breaker back on, then checked the noise level as each breaker was turned on. Found one breaker that seemed to increase the level but it didn't after it had been cycled a couple of times.

Now with all the breakers on I have S1-S2 noise level on 20m. A really easy fix and I wish I'd found it months ago. I suppose I should change the breaker for a new one before the problem comes back again.