Re: Octopus a real Doosey


"Cecil Moore" <nospam@xxxxxxxxx> wrote in message
news:G39Rj.23213$%41.3634@xxxxxxxxxxxxxxxxxxxxxxx
HRBE wrote:
Why are the 20m whips the only ones giving me trouble?

Probably what is happening is that you are getting a
self-resonance on 14.2 MHz from the 75m or 40m hamsticks.
That doesn't happen with 1/2WL fan dipoles but it certainly
can happen with hamsticks. For instance, if the self-resonant
feedpoint impedance of the 75m hamstick dipole is lower on
20m than the 20m hamstick dipole, you will not be able to
adjust the 20m hamstick dipole for a 1:1 SWR.

Using only the 75m hamstick dipole, find the 20m impedance.
Then do the same for only the the 40m dipole. You can
probably diagnose the problem but I don't know of a
solution.
--
73, Cecil http://www.w5dxp.com

I agree with Cecil,
One of the lower freq whip pairs is resonating on 20M and masking the 20M
whips' resonance.
Try this: remove the 20M whips and look for resonance around 20M When you
locate the pair of whips that is tuning up, run your finger up and down one
of their inductance coils.
You will likely find a great upset in VSWR along the coil- if more than one
is found, select the one closest to the base point. Mark this point and then
use something like copper tape and a 12" wire to capacity couple to that
point. This will have close to zero effect on the band the whip is intended
for, but, because it is a voltage loop on 20M, will have a major effect. The
idea is to move this whip pair's resonanace well below 14MHz.

Dale W4OP


.

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