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[TowerTalk] SGC-235 500 Watt Tuner

To: <towertalk@contesting.com>
Subject: [TowerTalk] SGC-235 500 Watt Tuner
From: n7cl@mmsi.com (Eric Gustafson)
Date: Fri, 5 Feb 1999 09:53:36 -0700

>From: MREISING@aol.com
To: <towertalk@contesting.com>
>Date: Thu, 4 Feb 1999 22:35:20 EST
>
>In a message dated 2/4/99 11:20:33 AM Eastern Standard Time,
>n7cl@mmsi.com writes:

> I had a very bad experience while trying to help a friend with
> his motor home mobile installation of an SGC tuner.  basically,
> the problem is as folows: 

Snip...


> We had the unit either replaced or repaired by SGC at least
> three times before giving up.  SGC became increasingly
> difficult to deal with as time went on.  They eventually
> refused to help with this unit any more.  The rig was an ICOM
> 736 with no amp.  the antenna was a 270 ish foot long piece of
> wire averaging 30 feet or so off the ground.
>
>
>I have been using an SGC 230 unit for about 5 years, both in
>mobile and long wire situations.  I had one problem with a relay
>about 3 years after I got the unit and SGC repaired it and
>returned it FEDEX overnight for no charge.  I think their
>customer service is excellent.

We did too for the first failure.


Snip...

>All of my radios automatically cut the power back to ~10 watts
>until the SWR goes down.

This is also true of the IC736.  But beyond this - after the
first failure, we set the AM carrier power output limit to 8
watts.  And used the AM mode for tuning operations exclusively.
So that regardless of how low the SWR went, the output power
during tuning operations was always less than 10 watts.  After
the second failure, we reduced this power to the minimum level
that the tuner would reliably function with.  This increased
longevity somewhat but did not make the system reliable in the
long term.

>I have noticed that the tuner will act flakey when there is a
>poor ground on the mobile so this may have been the problem n7cl
>was having.

We noticed the same thing.  In fact, that is why I was involved
in the first place.  When he initially installed the unit, he
couldn't get it to work at all.  It turned out that this problem
was due to inadequate grounding.  We didn't start burning up
relay contacts until the grounding problem was well solved.  Our
troubles with unit failures didn't begin until we had made
everything but the radiator wire RF "cold".  After that the
symptoms were:

1.  Install new or repaired unit.

2.  Verify that it tunes properly across all bands of interest
    (basically 80 meters up)

3.  I leave the RV park in NM and come back to Tucson.

4.  Owner of tuner remains and uses the system for a few days -
    to a few weeks - to (finally at very reduced tuning power) a
    few months - until relay contacts begin to fail.

    Note that if it was a bad ground, the problem would have
    manifested itself immediately.  Not after a period of time
    spent operating perfectly.  No aspect of the site or antenna
    system was changed prior to failure.  The only change after
    initial verification of proper operation was the passage of
    time.

5.  Deal with SGC to get the unit repaired.

6.  Repeat cycle from step 1 until SGC stops participating.

I don't know what kind of operating you do.  SSB may be easier on
these things than CW.  I don't know why it should but who knows?
At any rate, for the record, John is exclusively a CW operator.

73, Eric  N7CL

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