The only TRAPS in an X9 are in the DIRECTORS.
The DE is composed of a 4 element LOG CELL.
I've seen some comments about placement of
the feedline choke (and the feedline itself) when
using LOG Periodic antennas. I believe W8JI
had some input on that topic a while ago.
Tom N4KG
On Tue, 19 Nov 2002 "Tony Wanschura" <tonyjw@mindspring.com> writes:
> Immediately after putting up my Cushcraft X9 (with 40 meter add-on)
> about 3 years ago, I noted that the SWR on 15 and 20 meters was not
> as it should be. 10 meters was pretty much okay, but 15 and 20 were
> way out of range. On 15, SWR ranged from 2:1 at the bottom of the
> band to 5:1 at the top. On 20, the range was 3:1 at the bottom of
> the band and 2:1 at the top. A Minnesota winter was closing in, I
> operate almost entirely CW, and my rig's autotuner could deal with
> it. So I let the problem go until the following spring.
>
> Working on the assumption that I must have made a mistake in element
> dimensions, I took down the antenna and re-measured every dimension
> twice, finding a couple of 1/8 inch errors here and there. I put the
> antenna back up and, of course, nothing had changed. Discouraged, I
> walked away from the problem for nearly a year.
>
> This summer, I took the antenna down again, re-checked all
> measurements, removed the 40-meter element, and put the antenna back
> up. No improvement. All of this was a lot of work, since I have a
> guyed tower, with wire antennas hanging from it, and a 6-meter beam
> stacked above. I removed the wire antennas and the 6-meter beam.
> Still no improvement.
>
> I replaced the coax. No change.
>
> I am certain that all of the antenna dimensions are okay. The tower
> is 50 feet tall, with nothing around it that might cause an SWR
> problem. This leaves the traps as the cause of the problem. I
> suspect an outer (15/20 meter) trap on the first director.
>
> My questions are:
> Does the behavior described above suggest a trap problem?
> Has anyone else had a similar problem with the X7 or X9?
>
> Thanks,
> Tony
> KM0O
>
>
>
>
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