‰ NOW 35 WPM ‰ TEXT IS FROM DECEMBER 2018 QST PAGE 30 ‰ A VERSATILE T/R SWITCH FOR SDRS AND VINTAGE RADIOS THIS RF ACTUATED SWITCH CAN BE USED WITH ANY TRANSMITTER AND RECEIVER COMBINATION, BUT IT IS ESPECIALLY WELL SUITED FOR SOFTWARE DEFINED RADIOS. ROBERT NICKELS, W9RAN IN MY JANUARY 2013 QST ARTICLE, CHEAP AND EASY SDR, I INTRODUCED MANY HAMS TO THE WORLD OF SOFTWARE DEFINED RADIO SDR THROUGH INEXPENSIVE DVB T RTL SDR DONGLES AND OTHER SDR RECEIVERS LIKE AIRSPY, SPY VERTER, HF, SDRPLAY RSPS, HACKRF ONE, AND MORE THAT HAVE SINCE BECOME PART OF MANY HAM SHACKS. ADDING AN UPCONVERTER LIKE MY RANVERTER AVAILABLE AT WWW. HAYSEEDHAMFEST. COM TURNS INEXPENSIVE DONGLES INTENDED FOR DIGITAL TV RECEPTION INTO USABLE HF RECEIVERS WHEN OPERATED WITH PC BASED SOFTWARE SUCH AS SDR. BUT AFTER SOME INITIAL FUN, MANY SDR RECEIVERS END UP IN A DRAWER, BECAUSE THEY LACK SEVERAL KEY COMMUNICATIONS RECEIVER FEATURES NEEDED FOR USE ON THE AIR. I DESIGNED MY VERSATILE T/R SWITCH WITH THESE NEEDED FEATURES A PROVISION FOR MUTING THE SPEAKERS WHEN TRANSMITTING SIDETONE TO MONITOR CW KEYING A CONVENIENT MEANS OF SWITCHING THE ANTENNA BETWEEN THE TRANSMITTER AND THE SDR RECEIVER PROTECTION FOR THE RECEIVER INPUT DURING TRANSMIT A WAY TO OVERCOME DIGITAL SIGNAL PROCESSING LATENCY, WHICH MAKES IT IMPOSSIBLE TO MONITOR ONES OWN SIGNAL, AS CAN BE DONE WITH A CONVENTIONAL RECEIVER. WITH THESE FEATURES, ANY SDR RECEIVER CAN BE CONVENIENTLY USED AS PART OF A HAM ‰ END OF 35 WPM TEXT ‰ QST DE W1AW ƒ