‰  NOW 13 WPM  ‰
IF THE COMPUTER AND TRANSCEIVER ARE BOTH PLUGGED INTO AN AC OUTLET WITH A
SAFETY GROUND THE THIRD PIN ON THE POWER PLUG HOW CAN THEY POSSIBLY BE AT
DIFFERENT GROUND REFERENCES?  ONE POSSIBLE SCENARIO REVOLVES AROUND THE USE
OF AN EXTERNAL POWER SUPPLY WITH THE TRANSCEIVER.  THE POWER SUPPLY IS TIED
TO THE SAME GROUND REFERENCE AS THE COMPUTER, BUT THE TRANSCEIVER IS
CONNECTED TO THE POWER SUPPLY GROUND ONLY VIA THE GROUND WIRE IN THE DC
POWER CABLE.  WITH A 100 W TRANSCEIVER, THIS GROUND WIRE CAN HAVE PEAK
ƒ  QST DE W1AW  ‰
CURRENTS OF 20 A OR MORE FLOWING IN IT.  IF YOU CONNECT AN AUDIO GROUND
BETWEEN THE COMPUTER, WHICH IS AT THE POWER SUPPLYS GROUND REFERENCE, AND
THE TRANSCEIVER GROUND, IT ENDS UP BEING IN PARALLEL WITH THE SUPPLYS DC
POWER CABLE.  A SMALL PORTION OF THAT 20 A WILL FLOW THROUGH THE AUDIO
‰  FROM PAGE 108  ‰
A OK1SI 7,650 80 50 A OK2BDF 4,066 73 38 A OK6A 57,456 277 84 B OK1LO 49,
470 198 102 B OK2PMS 6,509 74 23 B OK1CAZ 3,888 58 24 B OK2BHE 3,460 43
‰  END OF 13 WPM TEXT  ‰  QST DE W1AW  ƒ