The noise might be picked up from the antenna, or, if you have common mode
currents on the feedline, along the feedline itself acting as part of the antenna.
Since the feedline runs closer to the electronic noise makers inside the house
than the antenna, this actually is a fairly common problem, and one that can
often be solved by installing an effective balun. It is possible to have it on
some bands and not others because the amount of common mode current
depends on the feedline length in wavelengths, along with many other
One thing you might try is to disconnect the feedline at the base of the
vertical and see if the noise level drops as much as you would expect. If
not, you may be picking up noise on the coax.
Certainly a good first step is to run the rig from a battery and shut off the
house power at the main breaker. If that makes a difference, then you can
kill the circuits one at a time to narrow it down. There are lots of noise
sources in the modern house - battery chargers, computers, TV sets (even
when off, if they can be turned on by remote control), heater controllers,
computer networks and routers, switched mode power supplies, CFL lamps,
etc. If you can narrow it down to part of your house, then a hand-held
receiver, or a small pickup loop on the end of a coax to your rig, might help
to sniff out where the noise is strongest.
If it is external to the house, then take the rig mobile with a loop antenna
(or whatever you can manage) and see if you can find where the noise is
But you are also fortunate to live in one of the few parts of the country where
there are a number of hams around who have hand-held 80m DF receivers.
They aren't perfect, especially when the noise is being propagated down
a power line rather than coming from a point source. But if you get stumped
otherwise, contact Joe Moell K0OV through his web site athttp://www.homingin.com/
and he may be able to find someone nearby who can help you.