No. Changing the feed line length to 1/2 wavelength wouldn't reduce loss
unless of course you actually decreased the total length of your feedline.
What it would do is present the tuner with whatever impedance is present
at your antenna's feed juntion which may or may not be of benefit.
If you are going to switch in those various lengths then you may as well
experiment and find the feedline length that presents the best match to
your 50 ohm rig and eliminate the tuner altogether. It is possible. Check
W6RCA's web site for more information on this subject.
That loop probably has a feedpoint Z of around 100 ohms at resonance on
it's fundemental frequency and around 300 ohms on the first harmonic. I've
managed to use a 4:1 current balun at the feed point, trim the coax for a
match on the fundemental and the harmonics fell within the 50 ohm ballpark
and eliminated the need for a tuner. It's really a great antenna.
We used one during Field Day cut for 80m and fed it with RG8 directly.
The auto tuner in the TS-870 matched it easily on every band.
> > Well, it arrived and after connecting it (there was one of the small
> wall-wart type connectors included in the box but I am afraid it was too
> difficult to solder, I wish TT would have included one with some wires
> attached) and finding a spare 12v at .5 amp wall wart with the correct
> connector), really had to look for the power requirements, they were buried
> in the manual text (sure wish TT would have included a sheet with the units
> specs as they do with everything else they sell ;-) I used it to tune 80,
> 40, 15 and 10 MT on my full wave horizontal loop at 20 ft. It did a very
> good job. We were having a snow storm at the time so I did not get into
> the other bands yet.
>
> My next question concerns the length of the coax between the ant and the
> AT-11MP. If this length were set to a multiple of 1/2 waves would the
> losses on the coax due to high swr be eliminated? I was considering having
> a switch that allowed me to insert the proper length of coax to achieve
> this condition and wonder what the benefit would be?
>
>
> Last, since the AT-11MP only needs 5w to work, is there a way to reduce the
> tune output from my scout down from 20w to 6w or so?
>
>
>
> Bill Ames
> KB1LG
>
>
> --
> FAQ on WWW: http://www.contesting.com/FAQ/tentec
> Submissions: tentec@contesting.com
> Administrative requests: tentec-REQUEST@contesting.com
> Problems: owner-tentec@contesting.com
>
>
Steve Ellington N4LQ
N4LQ@IGLOU.COM
--
FAQ on WWW: http://www.contesting.com/FAQ/tentec
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