=  NOW 20 WPM  =  TEXT IS FROM SEPTEMBER 2021  QST  PAGE 94 =

FILTERING FOR SSB USED 16 POLES FOR MUCH BETTER OFF FREQUENCY REJECTION.
FREQUENCY COUNTER AND DISPLAY THE SIGNAL ONE CX 7 HAD A BUILT IN PRECISION
FREQUENCY COUNTER.  THE DISPLAY READ DOWN TO THE NEAREST 100 HZ, USING NEON
NIXIE TUBE READOUT DEVICES.  LATER MODELS OF THE ORIGINAL CX 7 USED LED
SEVEN SEGMENT READOUT DEVICES ADAPTED TO REPLACE THE NIXIE TUBES.  EVEN
LATER VERSIONS WERE RETROFITTED TO USE THE LED SEVEN SEGMENT DISPLAY.  THE
DISPLAY AUTOMATICALLY READ THE FREQUENCY OF THE VFO CURRENTLY IN USE.
FLICKER OF THE 100 HZ DIGIT WAS NOT AN ISSUE FOR THE SIGNAL ONE CX 7 LIKE
IT WAS FOR THE HEATHKIT SB 104.  THE NIXIES ARE QUITE EASY TO READ, BUT
THEY ARE ESSENTIALLY IMPOSSIBLE TO FIND NEW NOW.  THE ONLY WAY TO GET A
REPLACEMENT IS TO SALVAGE A SUITABLE NIXIE TUBE FROM A DONOR PIECE OF TEST
=  END OF 20 WPM TEXT  =  QST DE W1AW  <