<VV> 'sparky' electrical question

[judynrandy at comcast.net]

I have a question.  When the gas heater in my '60 is firing, why can I hear the buzz on the stock am radio?  Earlier, I was also able to hear the turn signals "clicking" 
on the radio when used.  I figured it must be the radio noise suppressor condenser on the coil.  When I checked, sure enough, the wire was broken off.  I had a few in my parts stash, so I replaced it.  That cured the hearing of the turn signals issue, but not the gas heater.  Something else.  Whenever I drive close to where the radio station I listen to is located, the buzzing goes away!  But as I drive away from there and head home, the buzzing slowly returns.  Strange. 
All thoughts and ideas welcome. 
  
Randy (Cap'n) Hook 
'60 700 4dr '64'110/4spd