"Cecil Moore" wrote in message
...
Kevin & Natalia wrote:
Hi All,

I have just built a 20m dipole as a temp antenna for home.
I will be driving it with a TS-830 transceiver, which uses
valves in the final stage.
I know that I can only use it close to the cut frequency, but
want to build a small tuner to allow me to go off the cut slightly.
I only want the tuner to be used on 20m, so I do not need any
coil tapings for switching bands, so maybe a couple of caps will
do the job.

Look forward to any replies. Regards Kevin, ZL1KFM.

Hi Kevin, feed it with 450 ohm ladder-line. Make the ladder-line
length an integer number of 1/2 wavelengths. Then you can tune
your antenna system to resonance without a tuner by adding one
foot of ladder-line for lower frequency operation and subtracting
one foot for higher frequency operation. Varying the length of
the ladder-line by 0, 1, or 2 feet should cover the entire 20m
band. My resonant frequencies are 0' = 14.34 MHz; 1' = 14.2 MHz;
2' = 14.1 MHz. Of course, it doesn't have to be in one foot
increments. 35 cm increments might be better. :-)
--
73, Cecil http://www.qsl.net/w5dxp

Hi Cecil,

I know you like to tout ladder-line/tuned feeder as the solution for
everything from SHF to ingrown toenails... but don't you think you're
a bit over the top this time? Kevin should be able to get full-band
SWR under 1.5 using convenient coax feed, with no worries about
fussy window line, and no tuner of ANY kind, including tuned-feeder.
And you suggest he deliberately create a 5:1 or so SWR at the antenna
by using a mismatched feedline, just so he can have the joy of building
and using a tuned feeder??? Sheesh! Horses for courses, Cecil.

73, Ed


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