‰  NOW 40 WPM  ‰  TEXT IS FROM AUGUST 2006 QST  PAGES 56, 57 AND 96  ‰

PRODUCT REVIEW  MEDIUM TO HIGH POWER AUTO ANTENNA TUNERS THE EVOLUTION
CONTINUES REVIEWED BY JOEL R. HALLAS, W1ZR  QST TECHNICAL EDITOR  WE LAST
LOOKED AT A SELECTION OF AUTOMATIC ANTENNA TUNERS IN MAY 2004.  AT THAT
TIME, WE PICKED FOUR EXAMPLES, TWO DESIGNED FOR REMOTE OPERATION AND TWO
DESKTOP UNITS.  WHILE DIFFERENT IN MANY WAYS, THEY ALL WERE LIMITED TO 100
TO 200 W.  HIGHER POWERED AUTOMATIC ANTENNA TUNERS HAVE BEEN AVAILABLE, BUT
THEY WERE EITHER BUILT INTO HIGH POWERED AMPLIFIERS ICOM OR YAESU, FOR
EXAMPLE, WERE DESIGNED FOR REMOTE OPERATION AS IN THE SGC SG 235, OR HAVE
BEEN DISCONTINUED, AS IN THE CASE OF THE TEN TEC 253.  HIGH POWERED
AUTOMATIC ANTENNA TUNERS INITIALLY APPEARED IN THE 1980S THE HEATH 2500,3
J. W. MILLER AT2500, AND DAIWA CNA 10015 BUT THEY WERE NOT AS SOPHISTICATED
AS THE UNITS REVIEWED HERE, REQUIRING SOME MANUAL ADJUSTMENT OR PRESETTING
OF THE INDUCTOR FOR BEST OPERATION.  MODERN SOLID STATE TRANSCEIVERS AND
LINEAR AMPLIFIERS WITH THEIR NO TUNE OUTPUT STAGES HAVE BEEN WELL RECEIVED,
ESPECIALLY BY THOSE OF US WHO GREW UP IN THE VACUUM TUBE ERA.  THE TYPICAL
TRANSMITTER OF THAT TIME REQUIRED CAREFUL ADJUSTMENT OF THE TRANSMITTER
‰  FROM PAGE 96  ‰
335 4X1FQ/375 4X4DK/386 4X4JU/383 4X6UO/341 9A1HDE/353 9A2AA/364 9A2OM/342
9A2YM/353 9A4A/368 9A7V/341 9A8A/341 9A9A/344 AA1K/346 AA1V/348 AA4H/346
AA4S/358 AA4Z/358 AA7A/348 AA7AV/340 AB0X/348 AB8K/352 AB9E/346 AD5A/340
‰  QST DE W1AW  ƒ

TUNE, LOAD AND DRIVE CONTROLS, AT A MINIMUM, EVERY TIME WE CHANGED
FREQUENCY.  FAILURE TO DO IT RIGHT COULD RESULT IN DESTRUCTION OF THE FINAL
AMPLIFIER TUBES SOMETIMES A PRICEY PROPOSITION.  THE OTHER SIDE OF THE COIN
IS THAT THOSE TRANSMITTERS COULD BE ADJUSTED TO MATCH ANTENNA LOADS WITH A
MUCH HIGHER SWR THAN THE CURRENT CROP OF RADIO GEAR.  THE NO TUNE FEATURE
GENERALLY MEANS NO TUNE IF THE SWR IS 1R5 1 OR LESS, SOMETHING THAT OFTEN
DOESNT OFTEN FIT WITH REAL WORLD ANTENNAS AND WIDE AMATEUR BANDS.  THE
ANSWER HAS BEEN AN ANTENNA SYSTEM MATCHING UNIT, OFTEN CALLED AN ANTENNA
TUNER, EVEN THOUGH MANY WOULD ARGUE THAT IT DOESNT REALLY TUNE THE ANTENNA
RATHER IT TRANSFORMS THE IMPEDANCE AT THE BOTTOM OF AN ANTENNA SYSTEM TO
THE 50 THE RADIO EQUIPMENT WANTS TO OPERATE INTO.  SETTING SEMANTICS ASIDE,
IT SEEMS THAT THE CONTROLS WE USED TO HAVE TO ADJUST HAVENT DISAPPEARED BUT
HAVE MOVED FROM THE RADIO TO ANOTHER BOX THE ANTENNA TUNER.  ENTER THE
AUTOMATIC ANTENNA TUNER TO EXTEND THE NO TUNE CONCEPT ALL THE WAY TO THE
‰  FROM PAGE 96  ‰
AF2C/345 AG9S/344 AI9Y/340 AJ6V/346 AK1N/344 AL7R/341 P5NU/339 CT1BH/363
CT1BOH/341 CT1EEB/339 CT1RM/353 CT1ZW/354 CX4CR/355 DF2IS/341 DF2UH/340

IS A GREAT APPROACH IF YOU WILL BE TUNING A SINGLE ANTENNA FOR EACH BAND.
IN THE LDG AT 1000, THE LAST 200 SUCCESSFUL MATCHES ARE STORED INDEPENDENT
OF FREQUENCY.  A NEW MATCH REQUEST QUICKLY CYCLES THROUGH THE 200 TO SEE IF
A MATCH IS FOUND BEFORE IT BEGINS ITS TU
‰  FROM PAGE 96  ‰
DJ8NK/357 DJ9KG/347 DJ9RQ/352 DJ9RR/344 DJ9ZB/357 DK0EE/341 DK1FW/358
‰  END OF 40 WPM TEXT  ‚