"The Nearly Perfect Amplifier"

[RKILE at delphi.com]

    The nearly perfect combination of contributors to the September QST
Technical Correspondence reminds me of a comparison of Bill Orr's writings
that of Gordon West. It's hard to be an expert when there are so many
qualified experts out there.......Sometimes silence is the better part of
valor...................KG7D

via internet"rkile at delphi.com"

>From k3lr <k3lr at telerama.lm.com>  Fri Sep  2 04:54:36 1994
From: k3lr <k3lr at telerama.lm.com> (k3lr)
Date: Thu, 1 Sep 1994 23:54:36 -0400
Subject: Guys and Amps
Message-ID: <199409020354.XAA18243 at asia.lm.com>


Concerning the post by KM9P, to insulate, or not to insulate?
When I started building this station several years back, I researched
the guy wire interaction issue (this was before K6STI's GUY program).
I broke the 1/4" steel guys with preforms and A.B. Chance white D502
type insulators.  All looked OK until I started to notice that the
VSWR on any beam but 40 meters that has a guy set right under it,
varies as the antenna rotates.  Not only does the VSWR vary (some
antennas/bands were worse than others), the pattern gets distorted. 

The first band I went to work on was 10 meters.  I have 3 7 element
beams at 100'/66'/33' with guys at 99.5'/65.5'/32.5'.  I went crazy
with insulators.  The 1st section was 3' to the 1st insulator then 6',
6', 12', 12', 25', etc. No chance of a floating 1/2 wave, but the
VSWR/pattern problem was still there.  When I pulled the guys into the
tower, everything was perfect.  I gave up!  I know have phillystrand
for the 1st 50 feet of all guys where a beam is right on top of the
guy level and everything is great.  I had used the K6STI MNC and GUY
to model the effects before replacing the steel and it showed that
everything was fine.  However when I tole K6STI about the problem he
modified GUY to connect those 1st 3' sections together (as they are on
the tower) and depending on the face size of the tower, that causes a
interaction problem.

I have installed AG6K mods in SB-220s, L4Bs, Dentron amps, etc. Every
time I installed the mods, the amps were more stable.  The SB-220s
quit arching in the load capacitor, etc.  I think AG6K has some great
ideas, he is very willing to help on the phone and his prices are very
low.  Local 8877/3CX1200/3CX800 amplifier guru and QST author, K8RA,
is a AG6K fan.  

The AG6K mods might not be for everyone, but I wouldn't build an amp
without them.

73,
Tim K3LR

K3LR at telerama.lm.com

P.S. As WR3G reminded me, "It's less than 8 weeks till CQWW SSB,
better get the antenna projects done!"  I can't wait!