[TenTec] #253 Auto-Tuner

[The Motley Crew]

COMMENTS FOLLOW EACH POINT OF YOUR MESSAGE
73,
PUCK, W4PM

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?

SPECS SAY:
OUTPUT MATCHING RANGE: AT LEAST 10:1 VSWR, ANY PHASE ANGLE, 1.8 TO 30
MHZ. 1300
OHMS MAXIMUM PARALLEL EQUIVALENT RESISTANCE AT 1500 WATTS OUTPUT (2 KV
PEAK, >26:1
VSWR). 5000 OHMS MAXIMUM PARALLEL EQUIVALENT RESISTANCE ACROSS BALANCED
LINE AT 1500 WATTS OUTPUT (4 KV PEAK)

I'M NOT SURE WHAT ALL THAT MEANS BUT IT WILL INDEED HANDLE 1500 WATTS
OUT AS LONG AS THE LOAD IT SEES IS WITHIN ITS SPECS!  IT USES A SWITCHED
BANK OF DISC CERAMIC CAPACITORS INSTEAD OF A BIG AIR VARIABLE.  I'VE HAD
TWO TO FAIL IN THE SIX YEARS I'VE HAD MINE AND I SELDOM RUN THE AMP. 
FOR THAT REASON I WOULD NOT RECOMMEND RUNNING THIS TUNER WITH 1500 WATTS
FOR THE 48 HOURS OF A CONTEST!  OF COURSE I WOULDN'T ADVISE DOING THAT
UNLESS YOU WERE USING ONE OF THOSE MONSTER 10 KW TUNERS!

> 2. What does the internal meter read? Does it read both wattage and SWR?

THE METER READS SWR, 0-200 WATTS OR 0-2000 WATTS (4 SWITCH POSITIONS -
SWR, SET, 2KW, AND 200 W)
 
> 3. About how long would it typically take to tune a load (assuming the
> load is around 2.5/1 starting out)?

TUNING TIME VARIES BECAUSE TO GO TO A NEW SETTING THE ROTARY INDUCTOR
AND SWITCHED CAPACITOR BANK RETURN TO HOME POSITION FIRST AND THEN START
CRANKING IN INDUCTANCE AND CAPACITANCE.  ON 80 AND 160 THIS CAN TAKE
SOME TIME - UP TO 15 SECONDS - HOWEVER ONCE YOU HAVE A SETTING IN MEMORY
AND RETURN TO THAT SETTING IT IS VERY QUICK BECAUSE THE TUNER GOES
DIRECTLY TO IT. ON HIGHER BANDS WHICH REQUIRE LESS INDUCTANCE AND
CAPACITANCE TO REACH A MATCH THE INITIAL TUNING TAKES MUCH LESS TIME.

 > 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?

UP TO 28 PRESET CONDITIONS (7 BANDS X 4 ANTENNAS PER BAND) ARE SAVED IN
NON-VOLATILE 
RAM.  EACH TIME YOU RETUNE A SETTING IT USES UP ONE OF THE 10,000 OR
MORE SPACES IN
THE CHIP.  THIS SHOULDN'T BE A PROBLEM SINCE ONCE YOU SAVE YOUR SETTINGS
IN MEMORY YOU SHOULD SELDOM HAVE TO RETUNE.  IF YOU DO FILL UP THE CHIP
IT'S SIMPLE TO REPLACE. 
IT'S A LITTE 8 PIN DIP PACKAGE IN A SOCKET. I BOUGHT MY TUNER USED AND
HAD TO REPLACE
THE CHIP A FEW MONTHS LATER.  THE ORIGINAL OWNER MUST HAVE BEEN A REAL
TUNER UPPER!
SINCE THEN IT'S BEEN 5 1/2 YEARS AND NO NEED TO REPLACE IT AGAIN. 
 
> 5. What are some common problems associated with this tuner?

KEEP THE ROTARY INDUCTOR BEARINGS LUBRICATED.  I'VE HAD TO RELACE THE
INDUCTOR DUE TO BINDING BEARINGS.  HAD I PUT A LITTLE OIL ON THE
BEARINGS EVERY FEW MONTHS IT PROBABLY WOULD NOT HAVE HAPPENED. I'VE
MENTIONED THE TWO CAPACITOR FAILURES AND THE REPLACEMENT OF THE RAM
CHIP.  WHETHER THESE ARE COMMON PROBLEMS OR NOT I REALLY CAN'T SAY.  

> 
> 6. If you have owned one, what are your likes and dislikes? Any tricks of
> the trade or operational suggestions?

I LIKE THE TUNER BECAUSE I HAVE A SINGLE ANTENNA WHICH I USE ON ALL
BANDS. WHEN I CHANGE BANDS, MY PARAGON SENDS BAND INFO VIA THE REMOTE
JACK AND THE TUNER RETUNES TO A PRESET CONDITION FOR THE BAND. THIS IS
CONVIENT BECAUSE IT ALLOWS RAPID BAND CHANGES.  ONE PROBLEM IS THAT IT
ONLY HAS SEVEN BAND INPUTS AND THE PARAGON ONLY SENDS SIX OF THESE TO
THE TUNER.  I HAVE TO RETUNE FOR 30, 17 AND 12 METERS BECAUSE 40/30,
17/15, AND 12/10 ARE THE SAME BAND POSITIONS FOR THE PARAGON. 

TIP - MAKE SURE YOU PLACE THE TUNER IN THE BYBASS POSITION (EFFECTIVELY
CUTTING IT OFF) BEFORE YOU CUT THE POWER TO IT.  IF YOU DON'T, IT WILL
GET OUT OF SYNC AND NEED TO BE RESET.  NOT A REAL PROBLEM BUT A BIT OF A
BOTHER SINCE THE RESET TAKES 10 SECONDS OR SO.
   
> 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?

YES AND NO.  YOU CAN INDEED BUILD A 7 POSITION SWITCH AND PLUG IT INTO
THE REMOTE JACK
AND MANUALLY SEND THE TUNER 7 DIFERENT BAND SIGNALS.  THEN YOU MUST
CHANGE THE ANTENNA  
SWITCH TO SELECT THE FOUR POSSIBLE ANTENNAS PER BAND OR SWITCH
POSITION.  YOU CAN ALSO REMOTE THE TUNE SWITCH VIA THIS JACK.

ONE ADDITIONAL COMMENT - THIS TUNER IS NOT REALLY AUTOMATIC.  I'D CALL
IT MORE SEMI-AUTOMATIC. WHILE IT WILL GO TO A PREVIOUSLY SAVED SETTING
WHEN THE BAND INFO CHANGES OR THE ANTENNA SWITCH IS CHANGED, AND IT WILL
TUNE TO THE PROPER MATCH WHEN YOU PUSH THE TUNE BUTTON, IT WILL NOT
AUTOMATICALLY SENSE THE SWR CONDITION AND RETUNE ON ITS OWN. I GUESS
IT'S ALL IN HOW YOU DEFINE AUTOMATIC!

> 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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