Tom,
My experience says that measuring a stub is best when the expected R=0,
Therefore you want to leave the cable open for quarter wave length as it
reflects
Low Z at the feed end. The same length coax as the 1/4 wave on 40, will be
a 1/2 wave on 20m. In this case the termination should be a short as the
half wave transfers its termination Z.. You can short the cable to begin
with
if you like, but usually 1/4 wave cables shorted have a less pronounced peak
R vs the rather sharp null when open circuited.
Norm W4QN
===============================================================
Hi all
I just got a MFJ 259B and trying to set up some stubs.
On 40, there is a quarter wave stub, shorted on the end.
On 20, there is a stub the same length, only open.
On the 40 meter stub, do I just tune it for a RX=0, then short the end after
I measure it, or short the end and measure it that way?
And on 20, do I short the end, as in a 1/2 wave and measure it that way?
Thanks and 73
Tom W7WHY
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