[TowerTalk] Force 12 C4SXL - Intermittent SWR

[Richard Thorne]

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
>
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> ---------------------oOO---(_)---OOo-------------------------
> Albert C. Burnham, K6RIM
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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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