[Mobile-Portable] 97 Chevy Tahoe noise problem

[Dick Flanagan]

At 10:30 PM 8/1/2004, Scott Neader KA9FOX wrote:
 >Excellent idea.  I'll do it.  But can you tell me more about the "bare
 >braid"?  I have lots of 213 handy here.  But I'm not sure what you want me
 >to do with it, specifically.  My first guess is to cut the black stuff off,
 >then slide the braid off... and have them use just the braid?  But I'm
 >thinking that braid would be to thin/flimsy?

You've got the right idea.  Strip off the jacked taking care not to nick 
the braid.  Actually, with only a 12-inch length, you may be able to grab 
the center conductor with a pair of pliers and simply pull the jacket 
off.  Then it is a simple proposition to pull off the braid.

Remember the old Chinese finger puzzles where you push the ends together 
and they got big and then you pulled them apart to make them tight?  The 
braid is the same way.  Once you have the jacket off, push the two ends of 
the braid toward each other and the dialectic will slip right out.  Then 
pull the ends of the braid tight and you will be surprised how strong and 
condensed it will be.

When I am in bonding-frenzy mode, I will pull off about six or eight feet 
of braid and cut it into six-inch lengths.  Then I will stake-crimp a #10 
uninsulated lug onto each end.  I'll go down to the hardware store and get 
a box of #10 hex-head self-tapping sheet metal screws and a box of #10 
external toothed lock washers.  Then with my portable drill set to slow 
speed and with a quarter-inch socket adapter, I can bond an entire car in 
about twenty minutes:  doors, fenders, bumpers, frame, exhaust, hood, 
trunk.  The idea isn't to bond everything to the frame, but everything to 
each other!

In case you're wondering, the full-car bonding treatment isn't usually done 
to minimize ignition noise.  Yeah, bonding the exhaust pipe will do wonders 
for ignition noise, but the full treatment is usually reserved to provide a 
good radiation ground for your HF antenna.  You don't want your antenna to 
try to radiate off of multiple pieces of metal which happen to be moving in 
unison down the road.  You want the entire vehicle to appear as one solid 
piece of metal.  That's why you bond all of those individual pieces together.

So for right now, just go ahead and ground your exhaust system.  One ground 
toward the rear is usually all you need, but a second one just ahead of the 
muffler has been known to help stubborn cases.

73, Dick
--
Dick Flanagan K7VC NV SM
E-mail: k7vc at arrl.org