K9KL wrote:
>I just meant they needed to dip at the same freq, wherever they
were an odd 1/4 wavelength to make sure they REALLY were the same length.
Gregg, I did exactly that for my 3-stack on 10 meters.
If you are using one piece of coax, I doubt you even need to do
anything except cut both to the same physical length and then
just confirm with your MFJ. If you look at a model of a stack,
the pattern is fairly insensitive to slight differences in phase.
I recall seeing little difference for ~10 degree phase difference,
which is far more error than you would get by simply cutting
lines to the same physical lengths, even on 6 meters. I actually
used 2 different types of coax for my 3-stack. I used identical
types for the top and bottom, but used a different type for the
middle one. I recall it had a slightly lower Vf, allowing me to
make it shorter. This can create a very slight difference in
loss but nothing significant. I did this simply to use the coax
I happened to have on hand and it was an easy job to cut all 3
pieces to identical electrical lengths using the MFJ.
73, Bill W4ZV
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