[TowerTalk] SWR Problem with Tri-Bander

[Jim W7RY]

I would more suspect a trap.  More accurately, water in a trap.

The water or moisture is changing the resonance of the trap when it heats 
up. Especially because the problem is on only on 15 meters.


73 and good luck.
Jim W7RY




At 05:54 PM 2/22/2005, Joe Subich, K4IK wrote:

>N2EA writes:
>
> >
> > If it were balun connections, why would
> > it manifest only on 15 meters?
>
>I would be more inclined to suspect a problem with the beta
>insulators and/or the driven element insulator.  Although
>they are common to all three bands, the RF voltages are
>very different at those points (particularly the beta match)
>on each of the three bands.  If one of the insulators is
>cracked or has a small "pin hole," perhaps from lightning
>the RF stress could be causing heating, etc.
>
>Given that a TH3MK3 would be quite a few years old, I
>would be very tempted to order a complete set of insulators
>for the driven element and beta match.  In fact, the beta
>match was completely redesigned in the TH3MK4 to eliminate
>the insulators ... anyone know why?
>
>73,
>
>    ... Joe, K4IK
>
>
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