Hi Jim -- I assume you've tried what George suggested, without any luck,
but it is the right thing to do given the symptoms. Didn't you say that
the tap was already all the way to the antenna end of the coil (that's what
he's calling the hot end)?
I'd suggest you try removing all of the new radials from the circuit at the
ground stake, and see if things revert to the previous situation, just in
case something else has happened. You might also try using just your
transceiver and sweeping the band to see if it agrees that the antenna's
resonance is where the SWR meter says it is -- this in case you are having
some subtle problems from nearby AM broadcast.
73, Pete
At 11:23 PM 11/26/2004, George & Marijke Guerin wrote:
Jim,
Move the tap from the vertical toward the hot end of the loading coil
further to load the antenna down toward 1825 by putting more inductance in
the circuit.
For better ground add some more radials, not necessarily full 130 feet
long to better cover the ground currents close in, inbetween the full
length radials. Anything from 65 feet and up will do unless you intend to
end up with over 60 full length radials.
Good luck,
George K8GG
----- Original Message ----- From: <JSimon@GrahamDunn.com>
To: <topband@contesting.com>
Sent: Friday, November 26, 2004 6:45 PM
Subject: Topband: Vertical SWR problem
I've just installed a Titanex V160S vertical (87') with a V160AS (160m
only) tuning unit. Yesterday I connected 12 radials (130') each, adjusted
the taps on the tuning unit coil with an MFJ SWR analyzer, and got the
resonant point down to about 1850 khz. with tolerable SWR (less than
1.5:1) at 1805 khz. So, here's the problem: today I added another 16
radials, and the resonant point moved up to 1900 khz. The SWR is now high
enough at 1825 khz that the amp shuts down. I tried adjusting the taps on
the coil in the tuning unit, but to no avail.
Anyone have any suggestions as to how to get the resonant point to a
lower point in the band? Thanks.
73, Jim W1YY/7
(sorry for the duplicate message)
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