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