One of the selling points of the recently released SDRplay RSPdx is it's special High Dynamic Range (HDR) mode which can be used to improve signal performance for frequencies below 2 MHz. This mode should be especially useful in RF environments where there are strong signals that can overload the SDR and desensitize reception on weaker stations.
Over on YouTube Ivan (aka icholakov) has uploaded a video showing comparisons of signals being received with HDR mode turned on and off. He tests it on weak NDB DX signals, and on medium wave broadcast AM. The results do appear to show that using HDR mode results in an improvement in signal strength.
SDRPlay RSPdx HDR mode on and off - testing Non Directional Beacons and Medium Wave
Over on YouTube Tech Minds has posted a video of him using an Airspy HF+ Discovery to hunt for signals like non-direction beacons (NDB's) and other morse code CW beacons. The Airspy HF+ Discovery is a new software defined radio that builds upon the already excellent original Airspy HF+.
One key improvement that many people have been experimenting with is it's improved VLF and LF capabilities, which is where most beacons are. It is capable of tuning down to 0.5 kHz (500 Hz). Over on Twitter, @prog (creator of these Airspy products) has been experimenting with simple and small ferrite loop antennas for VLF/LF and finding excellent results due to the low noise figure and good impedance matching of the HF+ Discovery.
Hunting HF Beacons With An Airspy HF+ Discovery
Over on our new YouTube channel we’ve uploaded a video comparing the SDRplay RSP1 and RSP2 on reception of Non-Directional Beacons at around 350 kHz. Both radios had their gains adjusted for the best possible SNR and reception. They were connected through a splitter to a Wellbrook Magnetic Loop antenna. The Hi-Z port on the RSP2 was used as Port A and Port B don’t have good reception below about 1 MHz.
In all tests the RSP2 appears to have the better SNR, a lower noise floor and thus better audio, though from the spectrum view the RSP1 seems to have a little less spurs.
Subscribe and keep an eye on our new YouTube channel as soon we’ll be uploading more RSP1 vs RSP2 comparisons, Airspy vs RSP2 comparisons and other SDR related videos as well.
SDRplay RSP1 vs RSP2: MF Non-Directional Beacon Reception