‰  NOW 13 WPM  ‰  TEXT IS FROM JULY 2012 QST PAGE 55  ‰

ADJUSTABLE LINK THAT COULD BE MOVED CLOSER OR FARTHER FROM THE AXIS OF THE
INDUCTOR TO CHANGE THE AMOUNT OF COUPLING.  THIS ARRANGEMENT COULD
COMPENSATE FOR SOME CHANGES IN ANTENNA CHARACTERISTICS, BUT AN ADDITIONAL
DEDICATED ANTENNA TUNER WITH ADJUSTABLE COIL TAPS FOR DIFFERENT IMPEDANCES
WAS OFTEN PROVIDED TO DEAL WITH NONRESONANT OR OTHER MISMATCHED ANTENNA
LOADS.  AFTER WWII, COAX BECAME A POPULAR ANTENNA FEED LINE AND BY THE
1950S MOST HF TRANSMITTERS AND LATER TRANSCEIVERS USED AN UNBALANCED PI
ƒ  QST DE W1AW  ‰
NETWORK CIRCUIT AT THE OUTPUT.  THIS MADE BANDSWITCHING FEASIBLE AND
PROVIDED SOME RANGE OF COMPENSATION FOR IMPEDANCE DIFFERENCES, BUT IT WAS
REALLY DESIGNED JUST FOR UNBALANCED LOADS OF 50 75.  SOME TRANSMITTERS
ADVERTISED BEING ABLE TO OPERATE INTO LOADS OF 30 TO 600, ALTHOUGH THE
CIRCUITS WERE NOT OPTIMUM WHEN TUNED THAT FAR FROM THEIR DESIGN POINT.  AN
ANTENNA TUNER OR BALANCING ARRANGEMENT WAS NEEDED TO FEED BALANCED LOADS,
‰  END OF 13 WPM TEXT  ‰  QST DE W1AW  ƒ