If a thruhull is part of a bonding system there will be a wire (usually
green)
connecting all the underwater metals. Just disconnect it to isolate the
thruhull you plan to use. If you can pick up multiple thruhulls that is even
better. If you have access to a keel bolt then that is good too. I use
foil because the mesh seems to corrode away much quicker.

Doug
s/v Callista

"John" wrote in message
om...
"Doug Dotson" wrote in message
...
"Jerry Peters" wrote in message
...
Hello group - This is my second post regarding SSB installation

Three quick questions if I may. First, I understand that round wire
is
invisible in the grounding system and flat sheet or screen copper is
required/preferable.

That is true. Copper foil is used most often.

If screen is used, what are the critical characteristics - grid size,
wire
size, etc?

As far as I know it is not critical.

I am concerned that the screen is just a bunch of small round wires.

Not electrically.

Second question is related. It is
recommended to use several isolation capacitors for establishing the
connection to the engine or other DC ground to avoid a DC ground loop
between the antenna system and the radio. Once again, aren't the lead
wires
to the capacitors round wire and won't they "disappear" electrically?

Round wires don't eliminate the signal just attenuate it.

Third,
is it important to keep the ground plane below the water level?

Yes. It is intended to capacitively couple to the water.

My current plan is to laminate the interior of the hulls (catamaran),
above
and below the water line, with copper "insect screen" and tie it to
the
engine ground, water tank, etc with 3" copper straps and pull it all
back
to
a single point at the tuner.

Alot of work for not much gain. Just connecting the ground using foil
from the tuner and radio to a thruhull works just fine. The old methods
of running all kinds of mesh and foil has been pretty much debunked in
the
past few years. There have been a few articles on the subject. One I can
recall compared 1) mesh glassed into a new boat, 2) hanging the
ground over the side, 3) trailing the ground behind the boat, 4) tying
the ground to a thruhull. All systems were connected to a switch so that
the rig could be switched between the systems quickly. Result: no system
performed any better than the others in any substantive sense both
transmitting and receiving.

Make sure the thruhull isn;t part of a bonding system.

Opinions?

Jerry Peters

Doug, could you elaborate on the point of the through hull not being
part of the bonding system.
I am putting in a SSB next in week my '74 Swan 38. I have Monal water
and fuel tanks and bronze through hulls. I was planning on connecting
the tanks with a piece of mesh running through the bilge. Sounds like
you are suggesting that I would be just as well off to run a 1" foil
from the tuner to the first bronze through hull.
Thanks
John