On Oct 13, 8:39 pm, Larry wrote:
Brian Whatcott wrote :



I have silver at 0.0159 microhm meter at 20 degC
copper 0.0168 microhm.meter
gold 0.022 microhm meter

So gold may not be not quite as conductive as the best, but it
STAYS
at that value - no tarnish....

Brian W

I wish you guys would worry much more about "series inductance"
and lots less about how expensive you can make the damned ground
strap.

Look at your ground strap and follow it down to whatever is
supposed to be "ground" on your boat.

1 - Are there any sharp corners or folds back over itself to make
it look really neat, like boaters love their stuff?

This is bad, very bad. Every sharp curve increases the series
inductance, and inductive reactance. If it bends 90 degrees, you
have a 1/4 turn coil in series, raising the ground at the tuner
MUCH more than the total combined resistance of all the metal
chemistry in the circuit, which increases with frequency.

All turns in the ground strap should be as large a diameter as
you can make it and very smooth to reduce series inductance. It
should be routed in as straight a line from the tuner to the
ground as you can make it, for this same reason. This strap is
PART of the antenna. It radiates like mad when you're on the
air, into the bilge wiring, the reason why the LEDs in the DC
panel all light up when you talk. They're detecting the RF
induced into those DC cables in the bilge.

Now, let's put away the periodic tables and go reroute the ground
straps, taking off all the pretty tywraps and making them as
straight as possible, shortening them as much as we can.

Larry W4CSC and other fine old calls since 1957
--
Bruce will be by to inspect your installation, shortly.

Get a steel hull and just run a short wire to the hull. )

Grounding straps are for kids.

Joe

(Richard Casady) wrote in
:

And BTW
tarnished silver is the best, even better than gold.

The tarnish doesn't do anything good. On a relative scale,
silver is
250, copper 225, as is gold. Aluminum is 175. Stainless is
about like
lead, 6 or 8. Plain carbon steel is 25. Thermal conductivity is
closely correlated with electrical conductativity for what that
is
worth. Better at one is generally better at the other.

Casady



You boys worry about this WAY too much. Take a little reality
trip down to your favorite AM radio station and ask the engineer
if he'll show you the ground system at the base of one of the
towers. Don't touch the tower. It has kilowatts on it and the
arc will burn you. Notice how the bridge cables that have been
buried for 40 years look a little "tarnished" where you can see
'em. Half of 'em underground are just copper sulphate by now...
(c;

Your "tarnished" silver-plated ground strap is fine....mine, too.



Larry W4CSC and other fine old calls since 1957
--
You can tell there's extremely
intelligent life in the universe
because they have never called Earth.

On Sun, 14 Oct 2007 01:31:49 +0000, Larry wrote:

Your "tarnished" silver-plated ground strap is fine....mine, too.

It is well known that copper is somewhat soluble in sea water. After
all it was used to cover ships bottoms to retard marine growth. Had to
be in solution to be toxic. Silver is not very subject to attack. They
use it for medical work: I have silver wire in my jaw.
So, silver may well outlast copper in the ground. Life of either
should be long enough, in any case. They often ground electrical
transformers with a six foot or so copper rod driven into the ground
at the base of the pole. Fairly heavy conducters running down the
poles. I wonder if people steal them. They do get killed trying to
steal energized wire. You are supposed to ground your end of the
neutral, but whatever.

Casady

Evan,
I admit that I am not an expert in antenna theory, but the object of this
exercise is to establish a reflective ground plane for your long wire. The
obvious choice is the ocean. Why would anybody string anything inside the
hull? Not only would this wire be subject to corrosion due to electrolysis,
but this wire will always be less than optimum. What is wrong with an
insulated (from the hull) carbon block on the bottom of the boat with a
connecting stud for connection inside? This should deliver the required
connection without risk of corrosion.
Steve

"Evan Gatehouse" wrote in message
news:B3kPi.10444$th2.2814@pd7urf3no...
Never seen this discussed befo

Could I use thin stainless steel foil instead of copper foil in the bilge
as a ground for a long wire (backstay antenna) ham radio setup?

Evan Gatehouse

On Thu, 11 Oct 2007 21:42:01 +0200, "Steve Lusardi"
wrote:

Evan,
I admit that I am not an expert in antenna theory, but the object of this
exercise is to establish a reflective ground plane for your long wire. The
obvious choice is the ocean. Why would anybody string anything inside the
hull? Not only would this wire be subject to corrosion due to electrolysis,
but this wire will always be less than optimum. What is wrong with an
insulated (from the hull) carbon block on the bottom of the boat with a
connecting stud for connection inside? This should deliver the required
connection without risk of corrosion.
Steve

"Evan Gatehouse" wrote in message
news:B3kPi.10444$th2.2814@pd7urf3no...
Never seen this discussed befo

Could I use thin stainless steel foil instead of copper foil in the bilge
as a ground for a long wire (backstay antenna) ham radio setup?

Evan Gatehouse


I'm sure that Larry will comment on this but the foil inside the boat
forms a capacitance connection to the ocean, just outside the hull.

Many boats do have a "ground plate", a finned copper/bronze plate
bolted on the outside of the hull with connections made to one of the
mounting bolts inside the boat.

(The above assumes a fiberglass boat)

Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Thu, 11 Oct 2007 07:14:41 GMT, Evan Gatehouse
wrote:

Never seen this discussed befo

Could I use thin stainless steel foil instead of copper foil in the
bilge as a ground for a long wire (backstay antenna) ham radio setup?

Evan Gatehouse

Yes but it's relatively high-resistance compared with copper, silver
plate, or (preferably soft) aluminum sheet.

Brian Whatcott Altus OK

On Thu, 11 Oct 2007 21:25:14 -0500, Brian Whatcott
wrote:

Yes but it's relatively high-resistance compared with copper, silver
plate, or (preferably soft) aluminum sheet.

Funny you should mention soft. It is true that anything that hardens
copper or aluminum will increase electrical resistance. In the case of
work hardening, you beat dislocations into the crystal structure. Even
that has a very slight effect on the electrical properties. If you
have a joint between copper and aluminum immersed in the bilge water,
you may perhaps have some trouble with corrosion.

Casady