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From: (no name) (no email)
Date: Sun Mar 16 2003 - 12:05:44 EST
In a message dated 15-Mar-03 16:38:55 Eastern Standard Time,
writes:
> Would iron [embedded/internal] ballast do the same job as the steel in
> your ferro boat?
>
> If yes, how do you actually "utilize" this capability, please?
>
In my opinion, yes, to a large degree. As frequency goes up, it is easier
for energy to bridge the gap presented by insulation by capacitive and
inductive coupling.
Notice the windshield antennas on cell phones in cars. The coupling is only
by two plates glued on either side of the window glass, yet both the receive
and send signals can easily pass through.
To use the ballast you must be able to make an electrical connection to it.
If you have keel bolts you can attach to a keel bolt. If the ballast is a
lump of iron completely embedded in fiberglas then you must drill and tap (or
drill and drive a rod into) the iron. Be sure to use some sort of
anticorrosion like Never-Seeze, and I would use 316 or bronze for the rod.
It would also be good to use a strip of metal, or tinned braid to connect
this rod to the antenna tuner. Wide strips seem to work better than normal
wire for this, but a nice fat wire, like a battery cable, will probably work
almost as well and be more resistant to corrosion.
Bear in mind that since the ballast does not make a direct conductive
connection to the sea it would not be a good ground for normal ac and DC
power grounds or low freq (loran) signal grounds.
In the event of a lightening strike all bets are off. It could happen that
the lightening bolt would follow the ground wire into the ballast a blow a
chunk of keel off.
Ideally, one would make a heavy bronze keel shoe to fit over the outside of
the bottom and leading edge of the keel, bolted on with large bronze keel
bolts, with a bronze compression post under and connected to the mast to form
a low resistance straight line from the mast truck to the sea directly below.
This would minimize damage to the boat, but still might produce damage in
the bronze as witnessed by damaged bronze sea cocks and thru-hulls in
lightening hit boats.
However, voltage spikes induced in delicate electronic circuitry by the
massive currents in the lightening strike can still blow away all the
electronics in the boat. It only takes 10 volts in a device designed for 3
volts to completely wipe it out by arcing across microscopic places that are
supposed to be insulators.
Norm
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