In a recent YouTube video Tech Minds shows how to decode GMDSS (Global Maritime Distress and Safety System) messages which are broadcast on MW and HF. In the video he explains the DSC (Digital Selective Calling) which allows calls to be made to individual ships, a group or all stations. He goes on to demonstrate the YADD GMDSS DSC decoder running via the HF audio piped in from SDRUno and received with an SDRPlay RSPdx.
Over on YouTube user Tech Minds has uploaded a video showing how you can determine if you are getting HF interference from a VDSL internet connection going to your house or neighbors. VDSL or Very High Speed Digital Subscriber Line is an internet connection technology that runs over old copper phone wires allowing for a fast broadband connection. The frequencies used by VDSL are between 25 kHz to 12 MHz, and for VDSL2 up to 30 MHz. Unfortunately the frequencies used can result in high amounts of radio interference from RFI radiating from the copper phone lines which is a major problem for HF amateurs and short wave listeners.
In his video Tech Minds uses an SDRplay RSPdx to record a short IQ file of the VDSL interference that he experiences in his home in the UK. He then opens the IQ file in a piece of software called Lelantos, which was developed by a member of the UK amateur radio organization RSGB. If a VDSL signal is present, this tool will determine various bits of information about the interference, and will give you enough information to make a complaint to OFCOM, the UK's radio communications regulator.
Over on YouTube the TechMinds channel has uploaded a new video about decoding Differential GPS (DGPS) using an SDRplay RSPdx SDR. DGPS is a terrestrially transmitted long wave signal that is used to help correct and improve GPS position data calculations which may have timing errors due to atmospheric propagation delays. It works by broadcasting correction data calculated by the difference in received GPS location and the known location of the DGPS transmission site. DGPS is typically transmitted on longwave between 285 kHz and 315 kHz, but in Argentina there are two stations at 2570 and 2950 kHz.
In the video TechMinds explains how DGPS works, and some location around the world from where it is transmitted from. Later in the video he shows a DGPS signal being received by a SDRplay RSPdx SDR, and then show a demo of how it can be decoded with MultiPSK.
We note that there also various other DGPS decoders available including decoders for Android and iOS. A list of decoders can be found on the DGPS sigidwiki page.
Thomas from the SWLing blog has been playing around with the recently announced SDRplay RSPdx and has come out with a comprehensive review of the unit. In the review he also provides some comparison videos on real signals between the RSPdx and other SDRs like the WinRadio Excalibur, and Airspy HF+ Discovery.
In the review Thomas notes that while having the advantage of being a wideband receiver, the predecessor to the SDRplay RSPdx (the SDRplay RSP2) was never able to compete with the similarly priced Airspy HF+ and Airspy HF+ Discovery units when it came to HF, MW and LW receiving performance.
But now with it's 0 to 2 MHz enhanced HDR mode activated, Thomas notes that the new RSPdx is majorly improved over the RSP2 in terms of sensitivity and selectivity on the medium wave bands. Thomas' tests also show substantial improvements in the shortwave bands.
SDRplay recently released news about their upcoming RSPdx software defined radio, which replaces the RSP2 as the top of the line unit in the SDRplay lineup. The RSPdx is not yet on sale, but a few YouTube reviewers have already received their units. The first review comes from Mile Kokotov who is known to have reviewed several SDRs in the past. Mile's impressions are that the receiver works very well. He writes on his video blurb:
Today i have received the new SDR receiver from SDRplay, the RSPdx and was eager to turn it on and do some tests receiving on HF and VLF. Although at the moment my mini-whip antenna is not operational, I have connected some 20 meters wire as an antenna and start listening on VLF, LW, MW and HF...
I have to say that SDRplay team did a good job with this SDR-receiver, putting better filters and redesigning front-end to improve dynamic range and enhance overall performance in relation to its predecessors RSP2 and RSP2pro. The new RSPdx is very good indeed. Especially on HF and below.
The RSPdx has new features like HDR (High Dynamic range) mode for reception within selected bands below 2 MHz. HDR mode delivers improved intermodulation performance and less spurious responses for those challenging bands.
The second review is by SevenFortyOne who runs through the various features of the SDRplay and also tests it on various HF signals.
The third video isn't exactly a review, but here TechMinds shows us how to run the RSPdx as a panadapter on his FTDX-3000.