[RFI] Vehicle Ground Connections

Ed - K0iL k0il@arrl.net" <k0il@arrl.net
Thu, 10 Oct 2002 19:27:21 -0500

On Thursday, 10 October, 2002 5:46 PM, Sandel, Kyle W 
[SMTP:sandelkw@bp.com] wrote:
> What methods work best to attach an RF ground strap to the vehicle frame
> (for example, when grounding the vehicle tailpipe to the frame using 
> copper braid)?

I'll leave the "real" answers to this question to the motorheads out there 
who played with cars growing up; I played with radios and drove junky cars 
as a kid.  Spent all my spare money on radios and bikes (just like today!)

However, one thing to be careful in selecting materials for grounding 
whether in a car or in the hamshack:  Never place copper in direct contact 
with galvenized steel.  The galvanic reaction from the dissimilar metals 
will surely mean accelerated rust in the steel.  To avoid possible damage 
always use tinned straps, and replace when them worn.  Or use a brass 
interface to separate the two dissimilar metals.

Also, watch out for this when grounding tower guy wires using copper ground 
rods.  (The EIA standard now calls for galvanized steel ground rods.)  Just 
having the copper in the ground in the right (or wrong) soil conditions can 
cause the steel to break down rapidly.  We just replaced several guy 
anchors at work over the last 2 years due to this problem on our commercial 
500' towers.  One 4" C-channel anchor had a 1-1/2 inch hole all the way 
through it, and the remaining area was extremely thin and brittle .  We 
might've lost that tower in a few years had we not inspected it when we