Towertalk
[Top] [All Lists]

[Towertalk] Cushcraft X9 .. Bad trap?

To: <towertalk@contesting.com>
Subject: [Towertalk] Cushcraft X9 .. Bad trap?
From: n4kg@juno.com (n4kg@juno.com)
Date: Tue, 19 Nov 2002 19:07:28 -0600
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
> 
> 
> 
> 
> --- StripMime Report -- processed MIME parts ---
> multipart/alternative
>   text/plain (text body -- kept)
>   text/html
> ---
> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices, 
> See http://www.mscomputer.com 
> 
> Wireless Weather Stations now $349.95. Call Toll Free, 
> 888-333-9041 for additional information.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> 


________________________________________________________________
Sign Up for Juno Platinum Internet Access Today
Only $9.95 per month!
Visit www.juno.com

<Prev in Thread] Current Thread [Next in Thread>