Well, the tuners that come with marine sidebands (AT-140 etc) are
designed for end-fed long wires. Also, dipole lengths are specific to
the band one is working. Multiband operation would require some sort
of traps in both the backstay (sort of easy) and also matching traps
in the mast (really hard!). So in short, you can eliminate the ground
plane, but you also inherit less flexability. You also need to get an
antenna tuner that can tune a dipole. There has been some discussion
about tuning the entire rig (W4CCC) but I have no experience in
that area. Larry (W4CCC) also seems to have vanished from this
forum. I hope it was not a result of RF burns or that someone pointed
out there is no record of his ham licence in the FCC database

The elusive groundplane in the hull is a myth. Run foil from the tuner and
radio
to a thruhull and you are done. Make sure the thruhull is not part of a
bonding
system, it must be isolated. I wrapped the foil around a cockpit scupper
seacock and secured it with a hose clamp. I get excellent signal reports
and had no problems doing email from The Bahamas to dozens of land
station inside the US and Canada. Let me know if you want to arrange
for a QSO to check out my signal.

Doug, k3qt
s/v Callista

"Gordon Wedman" wrote in message
news:xhDEd.91279$KO5.69231@clgrps13...
Thanks Doug
So it would work well as an antenna for marine SSB?
If so I'm a bit surprised more people don't use this instead of trying to
achieve that elusive ground plane in the hull. Sounds like you could just
run the feed wire inside the mast if you don't need standoffs and the
whole installation would be pretty slick.

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...
That's a slightly different animal. It is acts essentually like a dipole
which is a balanced antenna. Balanced antennas do not need a
ground plane. Standoffs are not needed because the mast is part of
the ground side of the antenna which is what the shield on the coax
is. I experimentd with a real dipole by stretching it between the
masthead and the radar arch. It was fed in the middle with a balun.
Worked well, but
keeping the feedline out of harms way proved to be a problem.

If the antenna in question was fed with coax, a balun would be
desirable.

Doug, k3qt
s/v Callista

"Gordon Wedman" wrote in message
news:6wAEd.61994$nN6.13173@edtnps84...
Over the holidays I killed some time looking through a few back issues
of Cruising World. In the April 1986 issue a boat-based ham operator
said he used a top-fed backstay antenna with excellent results AND he
had no in-hull ground plane. He said he connected the shield from his
feed wire to the mast-side of the backstay and this allowed the mast and
all the standing rigging to act as a ground plane. He didn't say
anything about using stand-offs between the feed wire and the mast. I
would think you would get a lot of signal loss over that much length if
you didn't use stand-offs?
If a person could put up with the appearance and make sure the whole
set-up didn't get torn down by sails/running rigging, would this really
give good performance? I don't recall reading about this type of set-up
so I guess its not too common on recreational boats but maybe it could
be worth considering in some situations?