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Old February 5th 06, 08:59 AM posted to rec.radio.amateur.equipment
Roger
 
Posts: n/a
Default RF induction in car radio

On 1 Feb 2006 17:57:42 -0800, "
wrote:

I installed a VFH/UHF radio in a 1997 Grand Cherokee. The RF antenna
is approximately two feet horizontally, and slightly higher from the


2' is pretty close. I'd not mount them that close.

Jeep's radio receive antenna. If I was listening to the vehicle radio
and keyed the VHF radio, it would mute the vehicle radio. The vehicle


it was overloading the front end of the car radio which was causing it
to shut down, probably from the AGC, or actually driving the input
transistor into saturation.

radio finally is no longer working, except for one station. I am
assuming an induction problem. Technically, what exactly happened,
how, or not to fix the vehicle radio. How to prevent this problem in
the future. I raise this question not so much for the sake of the
Jeep, but because I am proposing to a put a VHF/UHF rig in the lady's
2005 Honda Accord. The only viable place on the car is a trunk mount.


Don't mount the ham antenna and the broadcast antennas within 2 feet
of each other. 4 or 5 feet would probably make the difference. They
are about 6 feet apart on my 4-Runner and I notice no interaction even
when running up to 160 watts on 2-meters.

It appears the car radion antenna is embedded in the rear glass and I
believe this area is also where the XM radio antenna is located. I


I doubt it'd bother the XM satellite antenna as that is so far removed
in frequency from the ham frequency, BUT it depends on how well
grounded that system is. If the feed line is not grounded right at
the window it could also pick up signal from the ham antennas.

have tried to contact Honda on various levels but have had no success.
I am wondering if I put the VHF radio in the car, will it "burn out"
the other radios. This should give something for a lot of
conversation. I hope I can get some help.


Any time you mix radio systems there is *some* risk. It may be
miniscule, and it may not. You should see what we have to go through
to get an IFR certified GPS system installed in an airplane. It has
to be tested "in flight" against all of the other radios in the plane
before it can be certified.

Then again, some where, some one will find a way to do it. I prefer
to let some one else find the best way. It's both easier and cheaper
that way. :-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


Thanks,
Ethan Davis KB3EGG