[TenTec] LDG Autotuner

Simmons, Reid W reid.w.simmons@intel.com
Fri, 12 Jan 2001 09:16:26 -0800


Scott;

I use the SGC-230 remote auto tuner and have never had any such problems
with my OMNI VI/3.  From my own personal experience I have found "antenna
tuners" (I know, I know, wrong terminology) to work great with balanced
antennas and feeders.  But when used with either coax or single wire
transmission lines, the tuner needs to be as far away from the shack as
possible.  That's one of several reasons that I chose the SGC over LDG and
others (LDG finally has a remote version of their tuner).  My antenna is a
200 foot wire with the SGC at the "feed point" which is about 2 feet from my
RF ground system.  The SGC is fed with about 30 feet of RG-8 from the Omni
and I have a Radio Works T4G Line Isolator connected to the input of the
SGC.  This setup works great with no interference from the SGC, Omni VI/3,
or computer.

Reid, K7YX


-----Original Message-----
From: Scott Walker [mailto:N3SW@worldnet.att.net]
Sent: Thursday, January 11, 2001 5:22 PM
To: tentec@contesting.com
Subject: [TenTec] LDG Autotuner



I find it interesting that TT may be selling the LDG 
autotuner, considering the problem I had using it in my 
Omni VI station.  I built one of them from a kit about 
2 years ago.  It went together very well and performed 
as advertised.  However, I noted an increase of QRN when 
operating full QSK CW with it.  I became very sensitive 
to internally generated noise in my shack because of 
this, and at first I did not realize it was the 
autotuner.  I simultaneously had a problem with the Omni 
6 "hearing itself" when certain parts of the front-panel 
display were active, and TT told me to add a bypass cap 
on the low-level board to fix that.  There was still 
another source of noise, and when I switched back to my 
old TT 4229 antenna tuner, that noise 
disappeared.  I called LDG, and with some discussion they 
speculated that I was hearing the processor in the 
autotuner between each CW character as the AT-11 sensed 
the SWR on the feedline.  This was most obvious on 
80-meter CW, where I operate daily (NTS nets).  The only 
solution was to defeat the autotune function entirely 
by lifting a diode lead (switching it to manual does not 
override the SWR autosensing) making the processor sleep.  
I decided this was too much trouble and have stayed with 
my old tuner.  I made TT aware of this problem.  So my 
point is, I might be the only guy who had this 
problem.  I will be interested to hear results as more TT 
users try out this autotuner.
73.
**********************************************************************
 Scott Walker
 New Cumberland, Cumberland County, Pennsylvania USA
 E-Mail: N3SW@worldnet.att.net
 CW: -.  ...--  ...  .--
**********************************************************************


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