>Carl's last point is important. A good ground is essential for the
>SSB/ham radio to work well, no matter what the antenna.
On the issue of the antenna, I think it's a waste of time to obsess
too much over the length of the wire, or configuration of it. Since
the SSB channel frequencies are all over the map, you're unlikely to
have a resonant antenna on many, if any, frequencies. A reasonable
length of wire (backstay), well matched by an antenna tuner, will
radiate your full transmitter power, assuming that the cable/wire
between the tuner and the antenna is not too lossy (you'll likely
have a high VSWR on that line/wire). Ham's are notorious for loading
up all sorts of things - random lengths of wire, coat hangers,
barbed-wire fences, bed springs - and still "getting out" OK.
Properly matched, they all radiate the full power. In what direction
they radiate, however, is another matter - it may not be in a useful
direction. For this reason, as much vertical (or horizontal) wire as
possible is a good idea, although even in these cases, at any random
frequency the radiation pattern will squirt some power in a useless
(say, very high angle) direction. Much of it, however, should be
fairly low-angle radiation which is what's desirable for long-range
communications.
Hal
AA2JQ
>This is exactly what I did on my sailboat years ago. I mounted the
>"tuner" (Icom AH 4) right at the base of the chainplate, inside. I use
>that plastic shroud cover over the bottom part of the backstay.
>Remember that the lead from the tuner to the backstay is part of the
>antenna and does radiate. Actually, everything from the output of the
>tuner on is antenna. There are certain lengths to avoid, depending on
>the bands to be used. I am familiar with the ham bands, but not the
>marine frequencies. The antenna doesn't need to be only 23 (?) feet,
>longer is better as long as the "bad" lengths are avoided. Wish I
>still had the chart. My backstay antenna is just short of 40 feet, and
>works good.
>Remember that the RF ground part is just as important. I have 4"
>copper strap from the bottom of the tuner run along the bottom of the
>boat, with connections to the keel and some thru hulls. The proof is
>in the performance. I've made 100's of contacts all over the world on
>various ham bands, even with the sunspot count near zero.
>
>Carl
>AB1DD
>
>
--
Hal Craft (AA2JQ)
Sailing Vessel "Talisman"
Currently asleep, Robinhood, ME
Berkshire, New York
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