Tony, is the A3's Front-to-Back on 10 meters about the same
as it was before the change in 20 meter VSWR (it is probably
worth checking front-to-back on 15 and 20 as well)? If the F/B
is unchanged, then it is probably an issue with the 10 meter
driven element traps. If the F/B has degraded noticeably, then
I would start checking the 10 meter traps in the parasitic
elements for problems. If you are losing 4 to 6 S-units, then
it is probably due to detuning in one of the parasitic elements.
That kind of signal loss due to problems in the driven element
would almost certainly be associated with a very very high
VSWR on 10 meters.
73 de Mike, W4EF....................
----- Original Message -----
From: "N2TK" <firstname.lastname@example.org>
To: "Towertalk" <email@example.com>
Sent: Tuesday, November 02, 2004 1:13 PM
Subject: [TowerTalk] A3 problem
> Looking for suggestions with a Cushcraft A3 problem. Up till this year it
> worked well. The swr was minimum at 14.1, 21.2, 28.4. Now it resonates at
> 14.5, 21.2, 28.0.
> Compared to a C3E on another tower at the same height, 35', 15 and 20M are
> comparable. On 10M, signals are down from 4-6 s-units on the A3 compared
> the C3! The element dimensions have not changed. I would guess it would
> to be a 10M trap. What else could it be? But which trap(s)? Puzzled that
> resonance didn't change.
> Was thinking of using a dip meter to check the traps.
> Any ideas or have you seen a similar problem?
> N2TK/NP2, Tony
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> TowerTalk mailing list
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
TowerTalk mailing list