Tom,
It seems interesting that the noise has increased over the past year and
also that the battery was replaced a year ago. Maybe there is some
cause and effect going on here. I'd be sure all connections are tight
and clean, and also try and rethink anything else that may have been
changed, adjusted, or tinkered with around the time of battery replacement.
I remember that you have had trouble with the screwdriver antenna tuning
system. Any correlation between the time the screwdriver failed and
the noise increased?
Good luck,
Steve KW3A