In article FuM9c.17580$Ft.5252@lakeread02,
"Garland Gray II" wrote:

They say there is no such thing as a stupid question, but I'm going to put
that theory to a real test.
I have removed a shroud from my catamaran to install insulators so it can be
used as the SSB antenna. Since there is no backstay as such, a main shroud
will have to do. However, I now find that the sparmaker who rigged the boat
is somewhat leery of my installing two more potential failure points in a so
highly loaded and critical support (of course, all are critical). He
suggests using one of the lowers, but these just won't be very long.
In the end I expect I'll continue with the original plan to insulate a main
shroud, but a thought came to me. The shrouds are inside a thick walled
plastic tube (which I had planned on removing), so I've wondered if rather
than using insulators I retain the plastic tube and secure a wire...or 2 or
3... along the length of the plastic tube as the antenna? I suppose the
presence of the grounded wire inside would interfere with the signal, maybe
not. Would it work?




The main ingerdiant for an MF/HF antenna is Electrical Length. If the
antenna is to short, it will not radiate properly in the MF portion of
the RF Spectrum. Yes, the autotuner will match a short antenna to the
radio, but it will not help the short antenna radiate that power
efficently. Longer is Better. Insulated shrouds can be effective
Antennas for marine use. It will not matter if the conductive
material is covered with insulative material. What wouldn't work
is to string and insulated antenna wire along a grounded shroud or
backstay, as the mutual coupling would destroy any RF Radiation.
I really liked the Kevlar Backstay with the antenna wire, either
inside, or alongside the length of the backstay. That is a very nice
idea, and would work well. I might suggest that one could add to
the Electrical Length, by using a spiral wrap on the antenna wire
over the Kevlar Backstay, as a way to improve the RF Radiation
Effecency of such a system.

Bruce in alaska
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add a 2 before @