‰  NOW 30 WPM  ‰  TEXT IS FROM JULY 2015 QST  PAGE 54‰

GETTING THE TRANSMITTER RUNNING AND USING IT ON THE AIR, BUT ASSUMES THAT
YOU ARE ALREADY FAMILIAR WITH THE RASPBERRY PI AND HAVE SET UP ITS
OPERATING SYSTEM, KEYBOARD, MOUSE, AND DISPLAY.  EACH MODE IS SUPPORTED BY
ITS OWN RASPBERRY PI PROGRAM THAT YOU INVOKE FROM THE LINUX COMMAND LINE.
THE GRAPHICAL FRONT END PROGRAM MENTIONED PREVIOUSLY MAY MAKE OPERATION A
LITTLE EASIER.  YOULL NEED TO DOWNLOAD THE SOFTWARE FROM RADWAVS WEBSITE.
WSPR OPERATION INVOLVES TRANSMITTING FOR 2 MINUTES AND WAITING FOR PERHAPS
6 MINUTES BEFORE SENDING AGAIN.  YOU NEED TO BE SURE THE PIS INTERNAL CLOCK
IS SET ACCURATELY, SO THAT THE MINUTE TICKS ARE ACCURATE WITHIN A FRACTION
OF A SECOND.  RADWAV WARNS THAT TRANSMITTING FOR LONGER THAN 2 MINUTES
RISKS OVERHEATING THE POWER TRANSISTOR.  THE PIS OSCILLATOR IS CRYSTAL
CONTROLLED AND STABLE, BUT NOT ESPECIALLY ACCURATE.  YOU WILL NEED TO
CALIBRATE IT AGAINST AN ACCURATE RECEIVER OR FREQUENCY COUNTER.  I FOUND MY
SIGNAL WAS RUNNING ABOUT 150 HZ LOW AT 7R04 MHZ.  THIS IS IMPORTANT,
BECAUSE THE ENTIRE WSPR BAND IS ONLY 200 HZ WIDE.  ITS EASY TO ADJUST YOUR
FREQUENCY SETTING BY CHANGING THE COMMAND LINE.  YOU CAN ADAPT THE PROVIDED
‰  END OF 30 WPM TEXT  ‰  QST DE W1AW  ƒ