=  NOW 40 WPM  =  
RSPDX CAN INDICATE AGC OFF, THE BLOCKING BEHAVIOR DOES NOT CHANGE WHETHER
THE AGC SETTING IS OFF OR ON.  BECAUSE OF THIS EFFECT, I COULD NOT MEASURE
EITHER BLOCKING GAIN COMPRESSION DYNAMIC RANGE OR RECIPROCAL MIXING DYNAMIC
RANGE FOR THE RSPDX.  A MORE DETAILED EXPLANATION IS AVAILABLE FROM WWW.
ARRL. ORG/ QST IN DEPTH.  RECEIVE PROCESSING DELAY TIME THE TIME BETWEEN
WHEN A SIGNAL ENTERS THE ANTENNA JACK AND WHEN IT IS HEARD IN THE SPEAKER
MEASURED 430 MILLISECONDS.  IF THIS RECE

PRODUCT REVIEW SDRPLAY RSPDX SOFTWARE DEFINED RECEIVER REVIEWED BY PASCAL
VILLENEUVE, VA2PV IN RECENT YEARS, SOFTWARE DEFINED RADIO SDR TECHNOLOGY
HAS BECOME VERY POPULAR.  BY TRANSFERRING PROCESSING TASKS TO SOFTWARE, SDR
TECHNOLOGY REDUCES THE HARDWARE COSTS, WHILE OFTEN INCREASING FEATURES AND
PERFORMANCE.  ITS ALSO EASIER TO UPGRADE.  THATS EXACTLY THE CASE WITH THE
SDRPLAY WIDEBAND RECEIVERS.  THIS BRITISH BASED COMPANY HAS BEEN AROUND FOR
A FEW YEARS.  BEGINNING WITH THE RSP1, ALL OF THEIR PRODUCT MODEL NAMES
HAVE STARTED WITH RSP, SHORT FOR RADIO SPECTRUM PROCESSOR.  IN 2016,
SDRPLAY LAUNCHED THE RSP2 AND RSP2PRO WITH METAL ENCLOSURE, AND THE RSPDX
REPLACES THESE RECEIVERS.  WE REVIEWED THE RSP2PRO IN THE OCTOBER 2017
ISSUE OF QST.  THERE ARE MANY APPLICATIONS FOR THIS SDR RECEIVER.  IT CAN
BE USED FOR ALL MODE LISTENING UP TO 2 GHZ, AND IT CAN BE USED TO SCAN
SEGMENTS OF THE SPECTRUM.  IT CAN BE USED AS A PANADAPTER WITH YOUR HF
TRANSCEIVER IF YOU HAVE ACCESS TO IF OUTPUT SIGNALS.  YOU CAN EVEN USE IT
AS A SPECTRUM ANALYZER WITH THE APPROPRIATE SOFTWARE.  THE SDRPLAY WEBSITE
FEATURES A LONG LIST OF HAM RADIO, INDUSTRIAL, SCIENTIFIC, AND EDUCATIONAL
APPLICATION NOTES.  OVERVIEW THE SDRPLAY RSPDX IS A WIDEBAND, FULL
FEATURED, 14 BIT SDR THAT COVERS THE ENTIRE RF SPECTRUM FROM 1 KHZ TO 2
GHZ.  COMBINED WITH SDRPLAYS SDRUNO SOFTWARE, YOU CAN MONITOR UP TO 10 MHZ

OF SPECTRUM AT A TIME.  THE RSPDX SHIPPING BOX INCLUDES ONLY THE RECEIVER.
YOU WILL HAVE TO PROVIDE A USB CABLE TO CONNECT IT TO YOUR COMPUTER, AS
WELL AS DOWNLOAD THE SDRUNO SOFTWARE AND DOCUMENTATION FROM THE SDRPLAY
WEBSITE.  THE RSPDX COMES WITH A METAL ENCLOSURE.  THE UNIT IS HEAVY FOR
ITS SIZE, AND IT WILL STAY STILL ON YOUR DESK.  THERE ARE THREE ANTENNA
INPUTS, AN EXTERNAL REFERENCE CLOCK INPUT, AND A USB CONNECTOR FOR THE
COMPUTER CONNECTION.  UNLIKE ITS PREDECESSOR, THE RSP2, THE RSPDX HAS NO
EXTERNAL CLOCK OUTPUT PORT.  IF YOU NEED A REFERENCE CLOCK OUTPUT, YOU WILL
HAVE TO MOVE UP TO THE TOP END SDRPLAY DEVICE, THE RSPDUO.  THE RSPDX FRONT
END HAS BEEN REDESIGNED FOR BETTER PERFORMANCE AT HF AND LOWER FREQUENCIES.
THE PRESELECTOR FILTERS AND NOTCH FILTER HAVE BEEN IMPROVED, ATTENUATOR
STEPS HAVE BEEN ADDED, AND THERES A NEW HDR HIGH DYNAMIC RANGE MODE WHEN
USED WITH THE COMPANION SDRUNO SOFTWARE.  COMPARED TO THE RSP2PRO, THE ARRL
LAB MEASUREMENTS SHOW SIGNIFICANTLY BETTER SENSITIVITY AT 630 AND 2200
METERS, AS WELL AS AN APPROXIMATELY 15 DB IMPROVEMENT IN THIRD ORDER IMD
DYNAMIC RANGE AT HF WITH THE RSPDX AGC LEVEL ADJUSTED FOR BEST DYNAMIC
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