[TowerTalk] SWR Problem with Tri-Bander

Joe Subich, K4IK k4ik at subich.com
Tue Feb 22 20:54:08 EST 2005


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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