Category: SDRplay

Web-Spectrum: Web-Based Spectrum Analyzer and GPS Signal Analyzer with RTL-SDR Support

Over on GitHub we've recently seen a new open source program release called "web-spectrum". Web-spectrum is a multi-purpose browser-based tool. One interesting feature is that it allows you to view the GNSS spectrum (via a connected RTL-SDR or SDRplay with an appropriate antenna), decode it to a position, and also analyze the signal for jamming. It uses gnss-sdr or Gypsum as the backend GNSS processing tool.

The tool can also be used as a real-time spectrum analyzer, and for this, it supports RTL-SDR and SDRplay as well as the tinySDR Ultra spectrum analyzer.

Finally, in addition to GPS decoding, it also supports ADS-B and ISM band decoding.

Web-Spectrum: A Browser based tool for spectrum analyzer, GNSS analysis, and ADS-B and ISM band decoding.

Guglielmo FM and DAB Receiver Software Updated to Version 0.7

Thank you to Marco for letting us know that his Guglielmo software has recently been updated to Version 0.7.

Guglielmo is an FM and DAB receiver for Linux, Windows and MacOS. It supports all major SDRs, including RTL-SDR, Airspy, SDRplay, HackRF, and LimeSDR. It is designed to be easy to use for media users rather than hobbyist technical users.

Version 0.7 adds the following features:

  • Raspberry PI appimage
  • UI improvements
  • Basic skins support
  • Logo handling

The new Raspberry Pi appimage, and binaries for other platforms can be found on the GitHub Releases page. Just expand the "assets" tab.

Guglielmo: Screenshot of the DAB Interface

DSDPlus Public Release Updated & Fast Lane Changes

The team behind DSDPlus has recently uploaded a new public release version 2.547. The last public release was version 1.101, released several years ago. Up until now, only DSD+ Fastlane customers have had access to the new version.

The new version adds new programs like FMP, which can be used to receive the FM signal from an RTL-SDR, Airspy or SDRplay SDR and transfer it to DSD+ over TCP. Previously, a program like SDR#, or SDR++ would have to be used along with audio piping software like VB Cable. 

Also introduced are numerous enhancements, including a single-receiver trunk-tracking mode that eliminates the need for dual SDR setups, a site loader GUI for rapid tuning and system selection, significantly expanded digital protocol support such as full P25 Phase II TDMA voice following, encryption algorithm and key ID detection, and GPS/AVL location and mapping capabilities. Hardware integration has also improved with features like bias-tee control for RTL-SDR Blog dongles, serial-targeted device selection, and smoother TCP-linked operation between DSD+ and FMP components.

The full list of changes can be found in the "Notes.txt" file in the DSDPlus zip file. The Radio Reference Wiki also has a summarized changelog.

The team also notes that they are now closing new signups to the DSD Fastlane program. FastLane was a program that allowed users to pay a small fee to receive the latest updates. They note that the program will remain active for users who have already signed up.

DSD Plus V2 Public Release with FMP24
DSD Plus V2 Public Release with FMP24

An Overview of 2025 SDR Black Friday Deals

Below, we're collating the best Black Friday sales we could find on SDR and related products.

If you find any other good sales for SDR or related products, please post in the comments!

RTL-SDR Blog

We're currently offering $5 of V3 dongles (including the V3c) on Amazon. The sale will last until Monday 1 December, and only while stocks last.

RTL-SDR Blog V3 Dongle + Antenna Kit: US$47.95 US$42.95 (Link)
RTL-SDR Blog V3 Dongle Only: US$37.95 US$32.95 (Link)
RTL-SDR Blog V3c Dongle Only: US$39.95 US$34.95 (Link)

We also want to add that in December, the price of V4 dongles will be raised, due to rising chip costs, and dwindling R828D stockpiles, so buying now is purchasing while essentially on sale.

We're also participating in the Airspy 25% sale with the YouLoop listing on our store. The sale takes the price down from $39.95 to $29.96.

Airspy

Airspy offers low-cost RX-only SDRs. Airspy is holding a 25% off Black Friday sale. Black Friday is usually their biggest discount of the year. The sale is offered by their official iTead store and by most resellers. Links to their sales are platforms available here https://airspy.com/purchase

Airspy R2: US$169.00 $126.75
Airspy Mini: US$99.00 US$74.25
Airspy HF+ Discovery: US$169.00 US$126.75
Airspy SpyVerter R2: US$49.00 US$36.75

SDRPlay

SDRplay offers low-cost RX-only SDRs. There do not appear to be any direct Black Friday deals from SDRplay, but on Ham Radio Outlet, the SDRplay nRSP-ST and DUO units are on sale. The RSPdx-R2 and RSP1B appear not to be on sale.

SDRplay nRSP-ST: $499.95 $399.95
SDRplay DUO: $299.95 $249.95

FlexRadio

FlexRadio offers high-end SDRs aimed at ham radio users. They are currently running a Black Friday deal as shown in the screenshot. https://www.flexradio.com/products/categories/black-friday/

Ham Radio Prep Course

While not physical SDRs, some people interested in getting their amateur radio licence in the US may be interested in this study course, which is discounted for Black Friday. https://hamradioprep.com/black-friday

They have various course bundles on sale, but this screenshot is of the full bundle.

A Video on Optimizing VLF Loop Antennas

VLF (Very Low Frequency) refers to signals in the 3–30 kHz range. Software-defined radios like the SDRplay RSPdx can pick up these signals with an appropriate antenna.

Over on YouTube, @electronics.unmessed has uploaded a video showing how you can build a high-performing VLF loop using a single loop of wire and a balun. The one-turn design results in a naturally low impedance at low frequencies. A balun is then added to step up the impedance, resulting in impedance compatibility with an SDR.

The video explains the concepts behind VLF loops using an equivalent circuit model and shows how conductor thickness offers little benefit above 10 kHz (though wide sheet conductors can add ~3 dB), larger loops scale with area but 2 m is a good indoor compromise, extra turns help small loops but underperform a single turn with a proper transformer, and alternative ferrite mixes give little improvement over standard choke cores. Ultimately, it is concluded that a one-turn loop with a well-chosen balun is one of the most effective designs.

If you're interested in similar content, there are also several other interesting videos on the @electronics.unmessed channel about VLF antennas, mag loop antennas, SDR reception, and more.

VLF Loop - What really Matters? (EP172)

Decoding ADS-C with a Cheap Aliexpress LNB and SDRplay RSP1B

Thank you to Nagy István for sharing with us his setup for decoding ADS-C with a 180cm prime focus dish, a cheap Aliexpress LNB, an Aliexpress bias tee, and an SDRplay RSP1B.

István receives the ADS-C signal from the Inmarsat 4A-F4 satellite, which he can see from his home in Hungary. 

István also notes the following information about the Chinese LNB:

This LNB original for DVB reception, but it works on Inmarsat reception, 3.6Ghz where ADS-C signals are, without any modification... But sometimes you need correcting frequency because of LNB oscillator drifting. I don't use dielectric plate, I don't have any material for this, at the moment.

Compared to ADS-B, which continuously broadcasts an aircraft’s GPS position and velocity to any ground station or nearby aircraft, ADS-C instead sends position reports via satellite, and is especially used over oceans and remote areas without ADS-B ground receivers.

However, ADS-C is relatively complex for hobbyists to receive due to the need for a large satellite dish and LNB to convert the 3.6 GHz frequency down to a frequency receivable by most SDRs. However, fortunately, as István shows, the LNB can be obtained cheaply these days.

Inmarsat ADS-C decoding with Jaero and Virtual Radar

ADS-C Being Received with an 1.8m dish, cheap Aliexpress LNB and SDRplay RSP1B.
ADS-C Being Received with an 1.8m dish, cheap Aliexpress LNB and SDRplay RSP1B.

A YouTube Review of the SDRplay nRSP-ST Networked Receiver

Over on YouTube Baltic Lab has recently uploaded an unboxing and review video of the SDRplay nRSP-ST. The nRSP-ST is the latest offering from SDRplay, and it is a networked software defined radio (SDR). This means that the SDR is designed to be mounted remotely and accessed over a network connection.

The video Baltic Lab unboxes the SDRplay nRSP-ST and then shows the setup and it receiving a voice signal from the International Space Station's (ISS) amateur radio repeater. During the test, the nRSP-ST is set up outdoors, powered via a portable battery, and connected to the network over WiFi. This shows how versatile the unit can be, allowing you to set it up in whatever location is best, without worrying about long coax runs.

He goes on to show some advanced settings, such as enabling public access, and how you can access the SDR via the SDR Connect software or simply in a browser on a PC or mobile device.

SDRPlay nRSP-ST Networked Receiver: Unboxing and Testing

SkyRoof: New Ham Satellite Tracking and SDR Receiver Software

Recently VE3NEA has released a new Windows program called "SkyRoof". SkyRoof is both a satellite tracking and SDR receiver program. It supports the RTL-SDR as well as Airspy and SDRplay devices.

The software is designed for tracking and receiving ham radio satellites, and it can provide detailed information about all ham satellites, tracking them in real time, and provide pass prediction. It also shows a skymap and SDR waterfall display. The receiver software supports demodulation of SSB/CW/FM, and it automatically compensates for doppler. It can also interface with antenna rotators that support hamlib.

SkyRoof Satellite Tracking and SDR Receiver Software Screenshot
SkyRoof Satellite Tracking and SDR Receiver Software Screenshot

Over on YouTube Johnson's Techworld has also recently uploaded a video showing him testing out Skyroof, which may be of interest to some.

Brief review of SkyRoof, the latest satellite tracking software!