[Icom] RE: Mobile Noise Supression Help Needed

[Dick Flanagan]

At 06:27 AM 8/21/2002, Denis G. Barton wrote:
 >Dick, what did you use to hold the RG-8 shield to the tail pipe?

I cut the braid to length and crimped an uninsulated lug on each end.  I 
then attached each end with a #8-3/8" self-drilling sheet metal screw with 
external-toothed lock washer.  Alternatively, take your car and the shield 
to a muffler shop and they will be happy to tack-weld each end to the frame 
and pipe.

Whenever I have a noise problem, I actually make up a dozen or so of these 
lugged shields and go around the car with my electric drill and bond every 
distinct panel to the body, frame or its adjacent neighbor:  hood, doors, 
fenders, side panels.  I also make it a point to crawl under the car and 
make sure the body is bonded to the frame in at least two locations.

But do the tail pipe first.  I can't speak for any vehicles other than my 
own, but this has always eliminated 80-90% of any ignition noise I was 
experiencing.

This does NOTHING for RF feedback or charging system noise ("alternator 
whine"), each of which require different methods.  My personal rule of 
thumb (I do a lot of mobile operating) is when I install a radio I am 
careful to ground the radio where it is mounted, run separately-fused power 
cables directly to the battery and ground the tail pipe.  Only if I then 
experience noise do I take further steps.

So far on both of my current mobile IC-706s (this is the ICOM reflector, 
after all), when I am monitoring 75 meters I can't tell whether my engine 
is running or not.  They are currently installed in an old 86 Ford F-150 
(aka pickup truck with Magnecor wires and full bonding) and a year-old 
Chevy Tahoe (aka Suburban with tail pipe bonding only).

If anyone would like any additional generic non-ICOM-specific help, please 
contact me directly at dick@twohams.com or join the mobile-portable@qth.net 
reflector.

73, Dick
--
Dick Flanagan W6OLD OOTC CFII Minden, Nevada
Visit http://www.cvrc.net