[TowerTalk] KT34XA WOES - FIRST HINT

[Larry G Schimelpfenig]

Hi yall. I'm the one having a problem with my XA on 15 - single dip up in
the phone band. You probably saw what the wx was like here over the
weekend (102-105 degrees with humidity to match), I didn't do any tower
work during that period!

One of the things I've been trying to figure out is how much the
parasitic elements effect the driven elements. When I removed the rear
director, the high band dip on 20 meters just disappeared. The single dip
on 15 dropped a couple hundred kcs. Remember my problem is that there is
no low band dip on this band. On ten I couldn't discern a high band dip
before removing D1, but the resonant frequency dropped as much as 600kcs.


I've been pretty well convinced that my problem is in the straps around
the capacitor tubes. Based on what has happened to the high end of each
band with the rear-most director removed, I'm willing to bet the effect
is the same with the low end of each band when the reflector is removed
(or looses resonance on a particular band). I have come up with an idea
that may improve the connection where the straps go around the capacitor
tubes. I'll let you know if it works.

At the moment, I'm aware of five hams that are having problems with the
KT34/KT34XA series. W1GD just told me has the same problem on 15 as I do.
He rebuilt his reflector and driven elements only to put it back up and
find no difference!
I put an XA up at K4CG in 1981 and when they took it down exactly ten
years later it worked the same as the day it went up. As several of the
guys have said, it is critical to get the dimensions correct.

Stay tuned. Photos in a light year!

73 de Larry K7SV


--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search