Brian Whatcott wrote in
:

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.

On Sun, 14 Oct 2007 01:39:43 +0000, Larry wrote:


I wish you guys would worry much more about "series inductance"
and lots less about how expensive you can make the damned ground
strap.
....
Larry W4CSC and other fine old calls since 1957


A valid point. But then, running an insulated wire underwater
has rather appreciable series inductance too
(which can self-tune at some frequency -
I wonder what fx that is? :-)

Brian W

Brian Whatcott wrote in
:

which can self-tune at some frequency

The only reason the boat has a tuner is we can't make an antenna
"self tune" but on a couple of frequencies.

All my ham antennas at home are "self tuning". No tuner is
required or wanted as they are so lossy.



Larry
--
You can tell there's extremely
intelligent life in the universe
because they have never called Earth.

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

Joe wrote in
oups.com:

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


You guys should see how well a Butternut HF9VX vertical ham antenna
works clamped to the handrail of the flight deck of the USS
Yorktown (CV-10) in Charleston Harbor....one of the "World's
Largest Ground Planes".

Her call is WA4USN, thanks to Senator Thurmond. The base of the
antenna is about 80' off the harbor surface.

Larry
--
You can tell there's extremely
intelligent life in the universe
because they have never called Earth.

On Sun, 14 Oct 2007 21:35:49 +0000, Larry wrote:
[Yorktown, CV-10]
about 80' off the harbor surface.

I guess people fall off of carriers and sometimes survive. Eighty feet
is a long drop. Good chance they won't find you, if it is moving. At
night, forget it.
Casady

(Richard Casady) wrote in
:

I guess people fall off of carriers and sometimes survive.
Eighty feet
is a long drop. Good chance they won't find you, if it is
moving. At
night, forget it.
Casady


One night, right after Yorktown came to Patriot's Point Naval
Museum's dock, a brisk breeze came up from the north, pushing
Yorktown away from her dock and big mooring pilings.

The lines snapped and Yorktown headed back out to sea floating
free off towards the port and passenger docks on the downtown
Charleston peninsula. The only man aboard was the astonished
security rent-a-cop screaming for help on his cellphone, all
alone on the monster. By the time the Navy tugboats got haulin'
ass downriver to take control of the derelict, she was almost
aground on Shute's Folly, a tiny island in the harbor. That
would have been bad. Navy tugs got her under power and put her
back at anchor at Patriot's Point. They couldn't dock her as her
dock was totally destroyed, hanging under her starboard side,
mostly.

To prevent this in the future, it was decided to SINK Yorktown,
permanently by pumping millions of gallons of fresh water into
her bilge compartments to put her on the pluff mud, then seal
those flooded compartments in wax to prevent it smelling. She
was then pumped all the way around with sand from a dredge to
insure her stability....well, at least into the far future when
the whole bottom will be rotted off her, creating someone ELSE's
Yorktown problem for the next generation...(c;



Larry
--
You can tell there's extremely
intelligent life in the universe
because they have never called Earth.

(Richard Casady) wrote in
:

I guess people fall off of carriers and sometimes survive. Eighty
feet
is a long drop. Good chance they won't find you, if it is moving.
At
night, forget it.
Casady


Sunk in sand like my last post shows, if you fall over the side,
you'll be falling into water that's a foot deep at low tide.
You'll die, instantly.

Larry
--
You can tell there's extremely
intelligent life in the universe
because they have never called Earth.