SV: [Elecraft] bonding of grounding systems

[W B Reese]

Dear Rolf,

Sorry to have been ambiguous; please pardon me.

If you peel back some RG8 Coax jacket, you can see an outer braid that is 
used for shield.  If you then cut the shielding braid and remove it from 
the center conductor and it's insulator you will have a wonderfully 
flexible and easy to work with braid that can be flattened into a 
"strap."  Over here, there is no need to cut up RG-8 coax, you can just buy 
the flattened braid by itself only and it is available in many convient 
sizes, many of which give you a much better and thicker braid than you 
would get by making it out of RG8.  This is what I refer to as braid, but 
you are correct, it is a form of :"strap."

On the other hand, if you go into a broadcast station and look at their 
medium wave tower, you will find a different kind of strap used at the base 
of the antenna.  It is solid copper with no braid in it.  I call this 
"strap" and it is solid because anywhere copper is exposed to moisture it 
will rust, resulting in copper oxide.  This solid strap is like a flat 
solid conductor, perhaps 1/32 of an inch thick and 3 or even 6 inches 
wide.  It is always laid flat and usually is silver soldered to resist 
corrosion for any bonds.

Often there is a "ground ring" composed of copper pipe about one inch in a 
circle around the tower and hundreds of #10 copper wires are silver 
soldered to it.  The copper strap forms a cross or an "X" with the 
intersection of the straps on the cement pedestal that the tower rests upon.

I'm sure we have all "grounded" pieces of equipment by virtue of their coax 
shields, and inside the station, protected from the weather, and inside the 
PVC plastic jackets of the coax, this is entirely adequate.  Indeed, one 
consideration inside the transmitter shack is the avoidance of ground "loops."

Due to it's availability and ease of handling, there is always a temptation 
to use braid where it will be exposed to moisture, and this inclination 
needs to be resisted!

Good luck to you Rolf & very 73,

At 04:31 PM 5/25/2004 +0200, you wrote:
>Hi,
>You said "strap". Braided strap is not a "strap" in normal
>english ?
>For not natives it may be a problem to understand what a strap
>is.
>If one says wide and solid strap is that a normal strap ?
>73
>Rolf SM0CLS/5
>
>Ämne: RE: [Elecraft] bonding of grounding systems
>
>Dear Ken & Ron,
>
>In my experience, using braid is a poor idea unless it is
>protected.  Moisture attacks the braid generating copper oxide
>and changing it from a single wide conductor to thousands of
>small conductors, all woven and the inductance is thus increased.
>That's why in every broadcast station I've ever worked at all the
>outside grounding is done with strap.
>
>TR WB6TMY
>K2/100/KAT100
>S/N 0838
>http://www.radions.net/spamfltr.htm