On the standard HF bands, one trick is to make the
75 ohm line a multiple of 1/2 WL on each band.
A line that is a multiple of 1/2 WL on 40M will
be 1 WL on 20M, 1.5 WL on 15M, 2 WL on 10M.
A line that is a multiple of 1/2 WL on 80M will
work on 80, 40, 30 (with some SWR), 20, 17, 15, 12, 10M.
Another approach is to use 75 to 50 ohm matching transformers
at each end which would work for non-harmonically related
frequencies.
The third approach is to just live with the small increase in SWR.
73 / GL, Tom N4KG
On Fri, 30 Mar 2001 23:02:40 -0600 "Michael Foerster"
<mike.foerster@home.com> writes:
> Is there a solution for matching 75 ohm hard-line to a triband
> antenna?
>
> I have a 6 meter, 2 meter and 440 antenna on my tower with 100 ft of
> 9913
> feeding it. At 440, it's probably about 6 dB loss. I would like
> to
> replace the bulk of the line with 75 ohm hard-line. I know that you
> can
> match the impedance with tuned matching stubs, but that's difficult
> to do
> with 3 different bands at once...
>
> Any suggestions?
>
> Mike
> W0IH
>
>
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