"stan" wrote in
oups.com:
No copper ground was needed
This antenna would be a HALFwave, not a quarter wave. The simple dipole
comes to mind. You'd have to have a separate dipole, or end-fed halfwave,
for each marine band...2, 4, 6, 8, 12, 16..etc. Not very practical on a
small sailboat. The formula for finding the length of this dipole or end-
fed halfwave is L = 468/F in Megahertz. Divide 468 by 2.182 and you'll get
214.5 FEET. How tall did you say that mast was on the little
Hunter??...(c; We COULD deploy it with a kite or gas-filled large balloon.
I've used huge advertising balloons to deploy large end-fed wires on 160
meter ham band (1.8-2.0 Mhz). Works great if the wind isn't blowing. Navy
used to include both kite and balloons in their AN/MAY-3 Emergency CW/AM
transmitters in the lifeboats way back. They worked fine on such low
powered, hand-cranked, tube-type transmitters.
But, alas, I haven't found it profitable on a 41' ketch.....(sigh)
By the way, the VHF version of the end-fed halfwave is already aboard our
boat atop both main and mizzen. It's the Metz VHF marine antenna. The
impedance matching transformer is in the base the coax plugs into. The
impedance of the end of the halfwave is quite high, so a large turns ratio
is needed to match it to 50 ohms. The Metz works fine with no ground. You
can even hold it in your hands, hanging onto the coax connector.
--
Larry
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