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terline ground system and attached directly to each piece of
low and high frequency radio gear.
While this may also seem to be an insurmountable problem in
running foil, rather than wire, foil handles quite nicely, even in
tight places. The foil is easily soldered to the below waterline
ground system, and then routed up the side of the hull into
the area of the NAV station. It may be glassed into the hull,
painted over, glued in, or even left resting on the side of the
hull. The foil may be bent in order
turn. If the foil must absolutely pass through a small hole, it
may be rolled up in a not-so-tight configuration and squeezed
through the orifice. Avoid a concentric type, for that type tends
to cancel oscillating radio frequencies. Flat is best.
There are several sticky marine compounds that will allow
the foil to adhere to the underside of a hatch, or to the side of
a hull. Almost anything will work, and there is little danger of
any substantial amounts of voltage developing on your
ground foil run. The ground foil and your complete RF
ground system, which run inside the hull, also will not sub-
stantially change your corrosion exposure to the seawater.
Galvanic corrosion problems occur when dissimilar metals
are immersed in seawater. The ground system is not actu-
ally immersed, its coupling is only capacitive.
Electrolysis is another form of corrosion where stray currents
may begin to eat up underwater metals. Good wiring tech-
niques for your 12-volt system independent of your RF
ground system will eliminate electrolysis.
Now let's get back to finding a spot to terminate that three-
inch wide copper foil that emanates from the below waterline
ground system. Most manufacturers of Loran weather fax
and marine single sideband sets don't provide an easy way
of adding ground foil to the stern end of their electronics! The
best method is to run the foil up to the back of the equipment
and use existing sheet metal screws to make a firm connec-
tion. Where a ground post stud with nuts and a washer are
provided, all the better— run the foil up to the stud, double it
back on itself several times for strength, punch a hole in it,
and then make the connection. Never negate all your hard
work of running the foil by using a small jumper wire to inter-
connect the foil to the radio set-up. You will be putting a
"weak link" in your ground system at radio frequencies.
We usually accordion up the excess foil in back of the equip-
ment so that we might remove the equipment for servicing
with the foil attached. If you put the bends in the right spot,
the foil will resume its natural collapsed state when the
equipment is put back in place. Watch out for the sharp cor-
ners on the ground foil, they are capable of piercing through
the plastic protective covering on electrical wires. Make sure
that red and black voltage carrying wires are not allowed to
rub up against the side of the ground foil.
We usually ground everything with foil at the navigation sta-
tion. This would include the casing of the wind
and speed equipment, pilot control box, GPS, sideband,
radar, VHF, and just about everything else that lights up. The
more grounding you provide for your central electronics, the
less problems you will have with stray RF.
The ground foil must also run to remote tuners. This includes
the ICOM single sideband tuner that's usually several feet
away from the equipment. These tuners may be all the way
back aft, adding another dimension to your ground foil run.
ANTENNA AND GROUNDING CONSIDERATIONS
to accomplish a 90-degree
It's best to run the foil from the RF ground source directly to
your tuner, rather than stringing everything out in series like
Christmas tree lights. Now picture one ground foil run from
the keel bolt to the electronics, and a second ground foil run
from the keel bolt back aft to the sideband tuner and your
stern-mounted Loran whip. These tuner ground circuits are
mandatory for any type of reliable operation. If you try to run
an ICOM sideband set with a remote tuner that is under-
grounded, you stand the chance of not only burning up your
equipment, but also damaging other electronics onboard with
stray RF. If it's not easy to run ground foil from your central
below the waterline ground source back aft, then try to fig-
ure out another way to do it. It has to be done!
You can also pick up additional ground counterpoise surface
area by adding substantial metals along the way in your cop-
per foil run. Stainless steel hose clamps make it easy to pick
up through-hull bronze fittings, water tanks, copper hydraulic
lines, and anything else that may give you some additional
underwater surface area.
Mariners with sailboats with poured incapsulated lead keels
as well as metal hull vessels have the easiest time in obtain-
ing a good ground counterpoise. If the keel is visible, a sec-
ond nut on the exposed thread will anchor on the ground foil.
We usually seal this connection to prevent deterioration from
the bilge water. It may also be recommended by local ex-
perts to tie in the aluminum mast to this close proximity keel
bolt for lightning protection. The run from the mast to the keel
bolt must be smooth, direct, and without sharp turns in order
to pass lightning energy effectively into the underwater lead.
Again, consult local lightning experts.
Steel-hulled vessels are easily attached to with foil by scrap-
ing away any protective coating from the hull, and making a
low resistant good surface area contact. Again, seal this con-
nection well. Non-metal hull or keel boats require yards and
yards of foil to be run below the waterline, anywhere you
can, and picking up any other large below the waterline tanks
and tubes.
SUMMARY
If you follow these steps, you will have an outstanding single
sideband signal that can be heard around the world. The dif-
ference between a good and bad ground is easily noticed on
transmission as well as reception. Since your ground coun-
terpoise is actually a part of your complete antenna system,
pay just as much attention to RF grounding as you did to
putting up that white fiber glass whip or installing to your in-
sulated backstay.
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