On Tue, 5 Sep 2006 18:24:08 -0600, "Bruce Wilson"
wrote:

I was thinking that maybe the efficiency of an antenna resonant at 3.5 MHz
would be poor at 3.8 MHz where I want to use it. If there is no diminution
of efficiency when the tuner fixes the impedance, then I'll just keep using
it as is.

Bruce,

I have some antenna system loss plots for a G5RV IV using different
types of feedline at http://www.vk1od.net/G5RV/index.htm .

There is a narrow optimal area around the 75/80m band, and the impact
depends on the length and grade of the coax used, ie the coax loss.
The exact frequency range will depend to some extent on your own
installation.

I would suggest that if you wanted to minimise the coax loss on
3.8MHz, you could adjust (shorten?) the dipole or the open wire
section, but that will also affect the other bands. Though it will
affect the other bands, the win on 3.8MHz might be worthwhile as the
antenna is less critical and lower loss on those higher bands on which
it performs reasonably.

Owen

PS: liked your pics, very impressive even when viewed at screen
resolution.
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