[RFI] Strange radio static problem in vehicle

Roger Parsons ve3zi at yahoo.com
Mon Jan 15 21:56:51 EST 2007


Further to the answers you have already received, this
used to be(?) a significant problem with large
military vehicles such as tanks, and had its own
acronyn - MMIC. Tanks commonly have (had?) several
HF/VHF radios operating simultaneously. Filtering
could remove interference when the vehicle was
stationary, but as soon as it started moving, the
breakdown of oil films and movement between parts, and
consequent instantaneous changes in the antenna
configurations, would prevent the use of more than one
radio.

I'm sure they have found a solution to it by now, as
this was over 20 years ago. I know I had similar and
horrible problems using full duplex radios on some
large underground mining machines which were only
solved by going to half duplex. The confusing part was
that increasing transmitter power increased
interference levels by exactly the same amount which
is certainly not intuitive.

73 Roger
VE3ZI



	
	
		
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