‰  NOW 20 WPM  ‰  TEXT IS FROM JANUARY 2015 QST  PAGE 99‰

EARLY DAYS OF THE NEW MODE, THE SSB RF SIGNAL WAS TYPICALLY GENERATED AT 9
MHZ.  THAT MAY SEEM AN ODD CHOICE UNTIL YOU CONSIDER THAT IF YOU MIXED THIS
SIGNAL WITH THE OUTPUT OF A VFO OPERATING IN A RANGE FROM 5 TO 5R5 MHZ, YOU
COULD USE THE HETERODYNE METHOD TO COMBINE THE TWO SIGNALS AND GENERATE AN
RF OUTPUT ON TWO BANDS.  IT WORKED LIKE THIS WHEN YOU COMBINED THE 5 TO 5R5
MHZ VFO SIGNAL WITH THE 9 MHZ SSB SIGNAL THE SUM WAS A SIGNAL BETWEEN 14
AND 14R5 MHZ, WHICH PROVIDED COVERAGE ACROSS THE 20 METER BAND.  TAKE THE
DIFFERENCE INSTEAD AND YOU GET AN OUTPUT IN THE 80 METER BAND 3R5 TO 4 MHZ.
ENGINEERS QUICKLY DISCOVERED THAT WITH THE PROPER APPLICATION OF THIS
HETERODYNE SLEIGHT OF HAND, THEY COULD CREATE A SINGLE CIRCUIT CAPABLE OF
GENERATING BOTH THE TRANSMIT AND RECEIVE FREQUENCIES.  NOW A SINGLE RADIO,
‰  END OF 20 WPM TEXT  ‰  QST DE W1AW  ƒ