[TowerTalk] Coax ground braid

[Jim Lux]

On 4/16/12 11:41 PM, Ian White GM3SEK wrote:

>> The better choice is wide flat copper
>> ribbon -- it lowers inductance a bit (but ONLY a bit) as compared to a
>> round conductor of equivalent cross section, and doesn't corrode as
>> quickly as braid.
>
> Well, strictly speaking it corrodes just as quickly :-)   The difference
> is that continuous strip doesn't have the problem of contact force
> between strands like braid does, so the corrosion on strip is far less
> damaging.

And, you could probably use strap/ribbon to bridge a hinge as well as 
braid, but you want to be careful about the alloy.  Pure copper probably 
would NOT be a good choice because of work hardening (getting brittle 
after being flexed) and the same thing applies to braid, by the way.

Phosphor bronze is tough, but I don't know about the conductivity.

Actually, now that I think about it, I can't think of many places where 
braid is actually appropriate, except as a shield over other wires or as 
solder wick.  Maybe something like bonding two pieces of metal that need 
to move a little bit, but that aren't oriented such that a piece of 
strap wouldn't work?

There is a "woven wire" that's very flexible used in things like motor 
brushes, but it's a special alloy that doesn't work harden.


BTW, strap is good when it's part of your vertical antenna RF ground 
system.  The inductance isn't much different from a wire of the same 
length, but the AC resistance can be a lot less.

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