RTL-SDR for HF 40m Band Scan


Since we are in the middle of Solar Cycle 25 (Ref.1/5), I might as well take advantage of excellent reception conditions on the HF bands. Up to now, I have used VB cable to connect SDR# to my decoder programs Multipsk/Fldigi. However, it is advantageous to be able to hear the signals while you are decoding them. My Win10 laptop does not have a stereo mixer as older versions did, so I added VB Audio Meeter to do this function.

Receive Block Diagram

Fig.1 HF 40m Receive Block Diagram

Figure 1 shows the receive block diagram. I am using the same setup as in previous posts, with the exception of using VB Audio Meeter to bridge the SDR# output both to the speakers and Multipsk. This allows me to view the decoding as well as listen to the signals. I tuned to the ARRL station W1AW (Ref.6) to receive a digital bulletin of RTTY45 and PSK31 on 7.095MHz at 18:00 then later on 7.045MHz at 20:00 for CW.

Fig.2 YouTube Video RTL-SDR for HF 40m Band Scan

Please send your comments, questions and suggestions to:

YouTube Channel
YouTube Channel


#1. – “HF Solar Eclipse Propagation”

#2. – “RTL-SDR for HF WWV Propagation”

#3. – “RTL-SDR for HF Beacons Propagation Predictions”

#4. – “Major Solar Cycle 25 Geomagnetic Storm”, June 2023 ARRL QST Magazine

#5. – “Experience the Wonders of Solar Cycle 25’s Solar Maximum”, May 2023 ARRL QST Magazine

#6. – “ARRL W1AW Operating Schedule”

By Jeremy Clark

Jeremy Clark is a Senior Telecommunications Engineer and Advanced Amateur Radio Operator VE3PKC. He is the author of E-Books on Telecommunications, Navigation & Electronics.