[TenTec] Question on 253 auto tuner

John - G3JAG patents@dx0man.prestel.co.uk
Thu, 13 Apr 2000 00:36:18 +0100 (BST)

Hi Dan

I use a 253 exactly as you say, except I have only a 40m inverted V
dipole at present. The balun is a Centaur ladderline to coax balun
and my coax run is around 20ft - the balun is hung outside high on the
wall so as to keep the ladderline from strangling anyone crossing the
yard. I use around 80-90 ft of heavy duty ladderline.

Yes, it covers 160-10m, although I cannot get a match on 160 with my
setup. I have worked a lot of DX on 80, but the 40m dipole is rather
short. Its rated generally similar to the 238 manual tuner, but I'm
limited to 400w here in UK. I have not run it at the 1500w level, but
magazine reviews I have here suggest there is no problem under normal
circumstances. (If you try end loading a hair pin on 160 then expect

There are four switched antenna output sockets and an internal balun
with binding posts for wire/ladderline. Each switch position has seven
memory slots associated with it. Using it with an Omni-V/Hercules II, I
set it up so that position 1 stores seven settings for non-WARC band CW
frequencies. Position 2 stores seven non-WARC band SSB frequencies.
Position 3 stores WARC band CW spots. (You need to do this because of
the ambiguous way some of the band select signals are generated by the
Omni. My approach does require an external 3-way coax switch).

Known snags/mods. There are two official mods which I know about. One
reduces the power needed to tune (30-50 watts). The other corrects an
SWR metering error. The non-volatile RAM chip used to store data has a
finite life and dies on you after very extended service. Replacements
were expensive here in UK, but I got three spares last week for around
$2 each. The trade outlet told me they have over 200 in stock. Looks
like this chip should not be a problem to get and in any case TT can
probably help.

If you get a used 253, make sure you get the manual and try to find out
if the mods were done. If the RAM chip was never replaced then its
worth thinking about getting one, especially if the tuner has had much
use. When it gets tired all sorts of weird things happen. Replacement
is fiddly.

Cost ??? How long is a piece of string ? The original cost was around
$1200; I got mine new, ex-demo, in a fire sale, for much less. Actually
I really wanted a 238 tuner, but there were none available in UK at that
time. They offered the 253 and I thought what the heck. I drove over
500 miles (all night in fact) to grab it before anyone else did. I was
lucky it needed only connecting cables and a coupling screw
re-tightening. It been in daily use ever since.

Remember its an obsolete gizmo. TT have been (as always) very helpful to
me, but the bottom line is that it is no longer made. 

73  John G3JAG

On 12-Apr-00 Dan Newby wrote:
> Can anyone tell me the general specs of this tuner?  Power
> capability, does 
> it cover 160m, impedance matching range, etc.  What are they selling
> for 
> now days?
> I would like to use one to tune a 260 ft long dipole fed with ladder
> line 
> up to the eve of the house. There it would connect to a balun and
> have 
> about 10ft of coax run in to the tuner. It would be nice to have an
> auto 
> tuner that has memories for band settings. Don't know if the tuner is
> that 
> smart.
> Thanks,
> Dan

E-Mail: John - G3JAG <patents@dx0man.prestel.co.uk>
Date: 12-Apr-00
Time: 21:58:23

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