"Wet-n-Wild Bill" wrote in
:

I forgot to mention that the boat is all metal (aluminum). You stated
that the strap should be short! my intent is to place the tuner three
to four feet from the antenna and mount it exposed to the elements on
the roof.

That would require the use of standoff insulators to hold the strap, even
insulated wire steadily away from the metal hull. If the wire is
flopping around, moving back and forth near the metal hull, it will
constantly detune then tune then detune the antenna, especially on some
frequencies where the impedance at the bottom of the whip is high. The
tuning solution needs to be fairly stable, so the wire needs to be
stable.


Any problems other than Dacron Guywires need when mounting on an
aluminum roof? Also on near by will be other RF cables for Weather
Fax and VHF, where as my GPS and Radar are 14' away!

Don't let the wire from the tuner to the antenna anywhere near any other
antennas. If it must be near other coaxial cables, these cables need
their shields bonded to the hull as soon as they go inside the boat to
prevent the outside of the coaxial shield from becoming an HF antenna,
leading the transmitter's RF right into the connector on the equipment.
Bonding is simple, out of the weather. Skin off a small ring of the
coax's outer plastic shield, wrap some wire around the outside of the
coax's braided shield, then ground that to the nearest screw into the
metal hull. This will drain off the RF at that point to hull ("ground")
so it doesn't follow the outside of the shield to the equipment the coax
belongs to.

Best would be small plate welded to the hull with coaxial connectors
running through it, those double female through-the-chassis connectors
with females on either end. The coax then uses standard coax connectors
to connect the cut cables to the plate's ground plane. Mine is a 4X8"
stainless plate with two U clamps to an 8' ground rod outside my ham
station. The RF following the cables down from the antenna, bleeds off
to the ground rod on one side. The RF going through the connectors, of
course, is INSIDE the cable and is unaffected. The outside of the coax
going into my house is RF free, now out of the antenna's big field. This
is a bigger issue when you're running 1500 watts PEP SSB...(c; POWER is
our FRIEND.