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Re: Question on 1/4 wavelength matching section




>> won't odd multiples of 1/4
> > wavelength perform the same transformation as 1/4 wave?).
>
> Yes but with reduced bandwidth. Off center frequency, the cumulative (1/4
> waves +/- a bit) make it less and less accurate.
>

Yes.  But without having an instrument that allows me to accurately measure
1/4 wavelength at 70cm, it makes it more practical for me to cut the cables
to 1/4 wavelength at 1/3 that frequency, which my test equipment can reach,
so I end up with 3/4 wavelength at 70cm.  I've not worked with any UHF
antennas before, but it seems to me that 1/4 wavelength at 70 cm is too
short to work with anyway from a practical standpoint.  Don't commercial
designs that need the matching sections use odd multiples of 1/4 wavelength?

<snip>

> Sometimes it's easier to consider the power splitter and the CP phasing
> entirely separately: example (A) combines both function and so can lead to
> confusion, although it is quite an elegant solution IMHO.
>
> 73 Howard G6LVB

Yes - the way you explained it made everything fall into place for me.  I
like the example (A) solution primarily because it allows me to make use of
a really neat low loss microwave relay I recently acquired - it's a 4 pole
with separate coils for each pole and you can activate any combination of
the poles at one time.  All I need now is a couple of "N" tee connectors.

The crossed yagi I'm resurrecting was saved from a dumpster by another ham.
It had a UHF tee connector, with two 24" lengths of 50 ohm coax going to the
yagi feedpoints.  I suspect it never really worked the way the original
owner thought it should, hence it ended up in the dumpster!  Thanks very
much for your clear explanation.

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