"Mike Knudsen"  wrote in message 
... 
 
 Long ago, like early '70s, Popular Electronics mag had a short article on 
how 
 to FM a 6m rig with a varicap diode across the oscillator tank.  Very 
short 
 parts list, and the most expensive item was probably the phone jack for 
the mic 
 input. 
 
 BTW, this article suggested FM as a way to reduce TVI -- not clear why it 
would 
 be less messy on TV picture or sound than an AM signal.  SSB was 
blissfully 
 rare on VHF back then.  --Mike K. 
 
I never understood it, but it seemed to work: those who tried FM reported 
that TVI *was* reduced. Since TV audio is FM, albeit at 25 KHz deviation, I 
would have thought it'd be *easier* to cause interference by using FM. 
 
Of course, perhaps it was a "second order" effect: perhaps it prevented 
*audible* interference, and therefore prevented anyone from identifying the 
source. I'd think that previous complainents might simply assume that the 
local ham whom they'd heard on their TV before was causing the picture to 
roll, but then again, I remember assuring neighbors that "If it was me, 
you'd hear me talking", so I might be wrong there ;-J. 
 
If anyone out there has the authoritative answer, please pass it along: did 
FM cause less interference, or did it simply prevent the interference from 
being in the audio chain? 
 
Enquiring minds want to know! 
 
Bill 
(Remove ".nouce" for direct replies.) 
 
 
		 
		
		
		
		
		
		
		
		
	
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