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[TenTec] #253 Auto-Tuner

To: <tentec@contesting.com>
Subject: [TenTec] #253 Auto-Tuner
From: patents@dx0man.prestel.co.uk (John - G3JAG)
Date: Sun, 21 Nov 1999 23:42:37 -0000 (GMT)
1. They say so. Its electrically very much the same as the 238. I have
never arced mine, but I only run 500w into it. You tune it at low power
(30-50 watts) so the relays should never have to switch at 1500w and
you should never turn the roller coaster at that level. 
2. It reads SWR and watts. I just use it to check the other SWR meters
around the place.
3. How long is a piece of string ? Depends on the band. If the band
setting is stored in memory its quick. Otherwise it can be half a
minute or so. Its faster on the HF bands than on 160.  
4. Correct, except that its 100,000 times ( I think). Mine took a lot
of use over several years. I bought some spare memory chips from a local
parts house and swapped the old one out. T*T usually stock them. The
worst part was removing the front panel. Make sure you have the right
Allen wrench to deal with the switch shaft coupling BEFORE you
start. Also, put it back carefully.
While you are in there, check the firmware number on the micro.  I think
the latest is 5.2 - but I got on OK with the previous version and I'm
thinking of swapping back to it. The chips are socketed - no soldering.
There is an SWR bridge modification you can do whilst the case is
open. I got the details from T*T; it fixes a minor bridge error due to
an earth loop. Note that it involves cutting a track and adding an earth
wire (fairly easy, but before soldering the free end of the wire its a
good idea to fix it temporarily with an alligator clip, so you can move
it to find the best null point). There is also a resistor change, to
reduce the power needed to re-tune.
4A. Note: If used with an Omni-V or VI, the band info supplied from the
rig is unique only for the non-WARC bands. That means that if you store
data for 40m then you have to completely re-tune the 253 for 30m,
because the band info from the rig is the same on 30 as on 40. The 30m
re-tune data is then stored, and if you go back to 40 you have to
re-tune again.
You do have 4 antenna switch positions. I used them to store (I) the
non-WARC cw settings for 7 bands (II) three WARC band settings for CW
and (III) 7 non-WARC phone band settings, etc.
BUT this means you have to use all the antenna connectors on the back,
and if like me you have only one antenna, you need an external switch to
connect the antenna to the right 253 outlet. (If you make a mistake you
will soon know about it).
5. See above about the memory and the firmware. I never had a
real problem with the earlier version; only the SWR bridge anomaly
irritated me. The mod fixed that, but the latest firmware seems to
remember the wrong L-configuration sometimes after switching off. When
I got the 253 (from a fire sale) the roller coaster drive coupler was
disconnected and I then discovered that I had a faulty roller. T*T sent
a 238 roller and I built a new one from the bits of both.
6. The 253 was discontinued some years ago. I only bought one because
there was no 238 available in the fire sale, only the 253 - and the
price was right !! I do like the thing, but its no longer current.
Unless its in good shape, complete with manual, and cheap, I suggest you
get a 238 .... Or build one.
7. See 4A above. I do not think an external box can be configured to do
exactly what you want. The limitation is probably the 253 control
logic/number of control lines. Its meant to be driven by the info from
the Omnis. If someone knows better, I'd be interested.

John G3JAG
 
On 21-Nov-99 Nat Heatwole wrote:
> 
> Hello and thanks a lot for reading. I'm considering buying a Ten Tec
> 253
> auto-tuner and am wondering if anyone could help me with any of the
> following general questions:
> 
> 1. Will it handle 1500w (or more) on SSB/CW from 1.8-30 MHz (even
> during
> hours of operation such as in contests)? Will it handle RTTY or tune
> the
> WARC's at full power?
> 
> 2. What does the internal meter read? Does it read both wattage and
> SWR?
> 
> 3. About how long would it typically take to tune a load (assuming
> the
> load is around 2.5/1 starting out)?
> 
> 4. I've heard that the RAM can only be rewritten over 10,000 times.
> What
> exactly does this mean and how could I replace it if it went bad?
> 
> 5. What are some common problems associated with this tuner?
> 
> 6. If you have owned one, what are your likes and dislikes? Any
> tricks of
> the trade or operational suggestions?
> 
> 7. Is there anyway to build/buy an external control box so that I can
> switch between all of the memory channels manually through one
> switch? Or
> can I only have 7 per antenna output? 
> 
> Please let me know if you can be of any help on any of the above
> queries.
> Thanks a lot and best 73.
> 
> Nat Heatwole
> KB3CBW in FM19
> 
> 
> 
> 
> 
> 
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----------------------------------
E-Mail: John - G3JAG <patents@dx0man.prestel.co.uk>
To: <tentec@contesting.com>
Date: 21-Nov-99
Time: 22:45:28

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