I have just put up a full wave loop on 160. I fed it directly with 50
ohm coax. A loop is suppose to be approximately 100 ohm antenna and I
figured 2:1 wasn't such a bad match. Well, it doesn't as good as a
dipole that I had up in another location.
Part of my reason for feeding this antenna this way was because I must
live with just one or two wire antennas for a short while and I wanted to
use the antenna on higher frequency bands with the built-in antenna
tuner. I know that I could use a 1/4 wave length transformer of 75 ohm
cable and make the match better on 160. How would that effect using it
on upper bands? I took down the feed point today and replace the dipole
center insulator with a 4:1 balun. That seems to make the radio happier
over a wider range of frequencies, but I have always heard that you
should not use a tuner with a balun. However, I doubt that this KLM KW
balun would be bothered by the minor amount of power put out by my
TS-450. What about using the 1/4 wave transformer, and then a matching
stub for the next band up that needs it? Should I use an open stub or
closed stub? How do I figure how long it needs to be?
73,
Carl
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