‰  NOW 40 WPM  ‰  TEXT IS FROM JANUARY 2014 QST  PAGE 65‰
WITH BOTH FEET, YOU MIGHT WANT TO TRY SOMETHING SIMPLE AND CHEAP.  FOR A
REALLY INEXPENSIVE SDR, TRY A USB DIGITAL TV DONGLE USING AN RTL2832U CHIP
THESE ARE AVAILABLE ON EBAY FOR LESS THAN 10.  FOR A PC, SDR SOFTWARE
SDRSHARP.COM WILL DRIVE THIS DONGLE, BUT IF YOU HAVE AN ANDROID PHONE,
CONNECT THE DONGLE WITH A USB OTG ON THE GO CABLE AND THE SDR TOUCH APP
SDR. MARTIN MARINOV.INFO CAN MAKE IT A PORTABLE BANDSCOPE.  FOR AN
INEXPENSIVE 10 GHZ RECEIVER, USE ONE OF 

WATERFALL DISPLAY OF THE PASSBAND YOU CAN SEE KEY CLICKS ON THE CW SIGNAL.
I FIND A WATERFALL DISPLAY MUCH MORE USEFUL.  IT DISPLAYS THE FREQUENCY
SPECTRUM AS A FUNCTION OF TIME, SO YOU SEE WHAT HAS HAPPENED ON THE BAND
FOR THE PAST FEW SECONDS OR, PERHAPS, A MINUTE OR TWO, DEPENDING ON THE
SETTING.  THE DISPLAY CONSTANTLY UPDATES, WITH THE OLDER DATA MOVING DOWN
AND FALLING OFF THE BOTTOM, LIKE A WATERFALL.  WEAK SIGNALS MAY FADE UP AND
DOWN, BUT THE WATERFALL CATCHES THE UP AND ALLOWS YOU TO TUNE IN THE
SIGNAL.  MICROWAVE SIGNALS MAY ALSO BE OFF FREQUENCY AND SUFFER FROM DRIFT,
PARTICULARLY ON THE HIGHER BANDS.  ROVER STATIONS CAN HAVE SERIOUS DRIFT
WHEN THE EQUIPMENT IS FIRST TURNED ON AT A NEW LOCATION.  FIGURE 2 SHOWS A
24 GHZ SIGNAL DURING THE 2013 10 GHZ AND UP CONTEST.  THIS SIGNAL FIRST
APPEARED AS A VERY FAINT LINE DRIFTING ACROSS THE UPPER WATERFALL DISPLAY.
IT WAS TOO WEAK TO COPY, BUT ONCE I FOUND IT, WE WERE EACH ABLE TO PEAK OUR
ANTENNAS USING THE PASSBAND WATERFALL DISPLAY IN THE LOWER RIGHT TO TRACK
THE DRIFT AND KEEP THE SIGNAL TUNED IN.  THE BANDSCOPE DISPLAY IS ALSO
VALUABLE FOR INTERMITTENT PROPAGATION, SUCH AS RAINSCATTER FROM A SMALL,

MICROWAVELENGTHS  PAUL WADE, W1GHZ, W1GHZ ARRL.  ORG BANDSCOPES,
WATERFALLS, AND SOFTWARE DEFINED RADIOS  PANORAMIC FREQUENCY DISPLAYS, LIKE
PANADAPTERS, ARE USEFUL FOR MONITORING BAND ACTIVITY, PARTICULARLY DURING
OPENINGS AND CONTESTS.  IN THE OCTOBER 2013 MICROWAVELENGTHS COLUMN, FIGURE
3 SHOWED A DISPLAY OF ACTIVITY DURING THE 2012 ARRL EME CONTEST.  FOR
MICROWAVE OPERATION, SIMILAR DISPLAYS ARE ALSO USEFUL, PARTICULARLY FOR
FINDING AND COPYING VERY WEAK SIGNALS.  THE OLDER PANADAPTERS WERE ANALOG
DISPLAYS, USUALLY PAIRED WITH A SPECIFIC RECEIVER.  SOME RECENT
TRANSCEIVERS INCLUDE A SMALL PANADAPTER DISPLAY ON THE LCD FRONT PANEL.
BUT MODERN SDR TOOLS PROVIDE A SIMPLE AND INEXPENSIVE WAY TO BOOST YOUR
WEAK SIGNAL WORK.  THE ADVENT OF SOFTWARE DEFINED RADIOS SDR BRINGS ENOUGH
COMPUTING POWER TO THE RECEIVER FOR MUCH MORE SOPHISTICATED AND CAPABLE
BANDSCOPE DISPLAYS.  EVEN BETTER, WE CAN REALIZE THE BENEFITS OF AN SDR
WITHOUT HAVING TO BUY A WHOLE NEW RADIO.  AN EXAMPLE OF AN SDR WITH A
TRADITIONAL PANORAMIC FREQUENCY DISPLAY IS SHOWN IN FIGURE 1, USING THE
HDSDR WWW. HDSDR. DE PROGRAM.  A 10 GHZ BEACON SIGNAL FROM MT MANSFIELD IN
VERMONT STANDS OUT IN THE MAIN DISPLAY, WHICH COVERS 80 KHZ THE SIGNAL WAS
SO STRONG THAT IT CAUSED SOME SPURIOUS RESPONSES IN MY RECEIVER.  IN THE
LOWER RIGHT IS THE SSB PASSBAND, SHOWING THE FILTER SHAPE AND ALSO A
‰  END OF 40 WPM TEXT  ‰  QST DE W1AW  ƒ