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[TowerTalk] Force 12 C4SXL - Intermittent SWR

To: <towertalk@contesting.com>
Subject: [TowerTalk] Force 12 C4SXL - Intermittent SWR
From: rthorne@arn.net (Richard Thorne)
Date: Sat, 20 Jun 1998 22:48:50 -0500
Hi Albert:

I have the C4XL.  I had the same problem on 40 meters only.  However, it was a 
bit different.  During receive my signal would be attenuated.  As soon as I 
would transmitt especially with the amp, I would get my normal receive signal.  
But the signal would go back to being attenuated within a few seconds.  It 
ended up being a  bad connection.  Did I
mention I hate PL-259's.  Actually, I rushed the job when putting the connector 
on.  I was too excited and wanted to get the antenna working.  As soon as I 
replaced the jumper between the feed point and the coax switch I was in 
business.

I'm betting you have a bum connection at both feed points.

Hope that helps.  You might want to replace the 40 meter coax first as its 
easier to get to.

G.L.


Albert C. Burnham wrote:

> I am having a peculiar problem with the C4SXL:
>
> When not using my amp, there is an intermittent SWR jump from resonance 
> (around 1.3:1) to around 2.5:1. This may or may not be affected by wind; I'm 
> not positive. But this problem occurs on all bands covered by the beam, 
> including 40 meters. (Actually, the SWR jump is more pronounced on 40 meters; 
> when the SWR is high, it is around 5:1 or 6:1).
>
> But when the amp is turned on, the SWR falls to normal.
>
> One possibility is bad coax or connectors, I suppose; however, there are TWO 
> separate runs of coax to the beam, one for 40 meters, and one for the other 
> bands. And, as previously mentioned, this problem occurs on all bands covered 
> by the beam.
>
> I also use a wire antenna, and the problem does not occur on it. The wire 
> antenna is wired through the same circuitry as the beam, ie, coax switch, 
> amp, low pass filter, SWR bridge, tuner, etc. -- this would seem to eliminate 
> internal shack wiring as the cause.
>
> There is a Force 12 balun for 40 meters, and one for the other bands. I doubt 
> that there could be two bad baluns. Also, if a balun were bad, putting more 
> power to it would probably make the problem worse, rather than better.
>
> One obvious solution is to always run the amp.
>
> But I would like to eliminate the problem.
>
> Any constructive comments/suggestions will be greatly appreciated.
>
> With thanks and 73,
>
> Al, K6RIM
>
> \\|//
> (@ @)
> ---------------------oOO---(_)---OOo-------------------------
> Albert C. Burnham, K6RIM
> 409 Summit Drive
> Corte Madera, CA 94925
>
> Phone: (415) 924-6783
> FAX: (415) 924-6678
> E-mail: w4rim@ix.netcom.com
> ----------------------------------------------------------------
> |__|__|
> || ||
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--
73,
Richard Thorne - N5ZC (ex KA2DSY, N2BHP, WB5M)
Amarillo, TX
Home Page: http://users.arn.net/~rthorne



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