"Bill Turner" wrote in message
...
On Fri, 26 Nov 2004 10:14:46 -0500, James wrote:

I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

__________________________________________________ _______

I'd say your system is working pretty well. 50 feet is too long for a
20 meter antenna, however. Your auto tuner is correcting for it, but a
shorter length will actually work better, since the auto tuner won't
have to introduce as much correction and therefore will have lower loss
in the tuner itself.

The vertical part of a ground plane antenna (which is what you have) can
be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet
(rounded off). The exact footage depends on variables in the immediate
environment, but that should be close enough. If you have to have a 50
foot overall wire because of the height of the boat's mast, just put an
egg insulator at the 16.4 foot length to break it up. For multiple
bands, figure the length of each section and put egg insulators where
needed, and then to change bands, just connect a jumper wire across
various eggs to get the correct length. Neat, huh? :-)

Also, you can't have too much ground area, within reason. More aluminum
foil or copper is always better.

If you have access to an SWR analyzer such as the MFJ 259, so much the
better. They are highly recommended for making and troubleshooting
antennas.

--
73, Bill W6WRT

Bill,

50 foot is only too long if you are sticking with the resonant length
situation. Which is not really necessary with his setup. In fact he
probably gets better versatility with the longer length. Just an opinion.

Dan/W4NTI