How about trying to locate the source of the noise? Is it in your
house or is it in the neighborhood? It could be something simple like
a streetlight buzzing a couple of blocks away. The power company
USUALLY pretty good about fixing those kinds of problems. Walk around
with a portable AM or shortwave radio and see if you can find the
offending pole or whatever. If the noise is in the house, like a
dimmer switch, or a tap on lamp, or an appliance, you can fix all that
easy enough too.
I'm also wondering about your rigs noise blanker. Most modern radios
have pretty darn good NB's. Its not a cure, but it should be
reasonably effective, unless the noise is a total monster. In that
case, all the more reason to find out where its coming from.

Good Luck K2TL