KT-34 Problem Resolution

Tue Oct 17 18:02:38 EDT 1995

A couple of months ago, PHil, KF6A, decided to remove his KT-34XA from
the tower and put up a KT-34.  His reasoning was that he had worked
almost all of 'em on 20-10 and that a rebuilt smaller antenna would keep
him from climbing the tower on a regular basis.

Down went the XA, up went the 4 el version. Checked SWR's, looked ok.

Phil proceeded to apply the come - along to the mast, get it up to 90
feet and put his rotator back in place.

Now he's eyeing the 2 - el 40 KLM that we pieced together from a couple
of dipoles.

I asked him when we were going to put up the 40 and he replied, "Well,
I've got some kinda trouble on the tribander.  We may have to pull it
down to work on that first."
So - KJ6TC and I go over on Sunday morning with the AEA antenna analyst,
look at the curves at the shack end of the coax and roll our eyes in
disgust.  "Everything has shifted up 3 or 4 hunnert kc's", sez Phil.

Don confirms this observation with magic meter.

Conjecture at this point is phenomenal.

Up the tower goes Don with the analyst.  He pulls the short stub from
the antenna side of the relay box off and applys the test set again.
"It looks fine here", he yells down.

Phil sez, "I wonder if that short piece of coax that I put in when I
raised the mast could be the trouble.  If I remember correctly, I think
I stressed it in the heat of battle with the come - along."

Down comes the suspected piece of feedline - up goes the substitute.

A re-check of swr's with the 765's meter (backed up with a Bird 43)
shows all is well again.

We looked at the now convicted piece of coax.  It was necked down to
about 2/3 dia. for about 6 inches.  I guess the Z sub zero was no longer
50 ohms for a little bit.  I suppose we transformed the non - 50 ohm (no
antenna's perfect) input of the KT-34 to something else at a different

Is there a moral to this long and probably boring story?  I don't know.
How about conservation of enthusiasm.  The 49'ers lost.  Balance is

At least we didn't have to bring the antenna down.  Strange, though - I
thought that the month of October would dictate the worst.

GL to all in CQWW SSB.


Eric, NV6O
edwoods at pacbell.com

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