Category: RTL-SDR

Understanding Single Sideband Modulation Through GNU Radio and RTL-SDR

Thank you to Paul Maine for writing in and sharing his latest tutorial video, which explains how Single Sideband (SSB) modulation works. In the video, Paul explains the concept and mathematical principles behind SSB by showing how to create an SSB receiver using GNU Radio and an RTL-SDR.

Paul writes:

Paul Maine “ The SDR Guy” recently released a video about Single Side Band (SSB). 

The SDR Guy shows how to create a single sideband receiver using GNU Radio and an RTL-SDR. He also shows how to modulate SSB signals. Paul collaborated with Gary Schafer in the production of this video. Gary has created a must read blog post on SSB.

Paul answers the question: What is SSB and what’s the advantage when compared to Amplitude Modulation. He used SDR++ to capture an IQ file using an RTL-SDR and his HF antenna and is included in his resources. This allows you to use the resources he has provided to demodulate SSB even if you don’t have an HF antenna.

In fact, you don’t even need to have an SDR. A GitHub link is provided in the video description to all flowgraphs and IQ files discussed in the video. Lastly, The SDR Guy has included a complete Upper and Lower Side Band receiver that’s implemented in GNU Radio using an RTL-SDR!

Be sure to look at his YouTube Channel (paulmaine6433). He has many other SDR related videos.

E17 Create Single Sideband Receivers with GNU Radio and RTL-SDR

An SSB receiver in GNU Radio
An SSB receiver in GNU Radio

RF Analyzer V2.0 Released: RTL-SDR Compatible Android App

Thank you to Dennis Mantz @dennismantz for writing in and sharing with us the news that RF Analyzer V2.0 has been released for Android devices. RF Analyzer is a popular multimode Android app compatible with a vast number of SDRs, including the RTL-SDR. It also now supports the RTL-SDR Blog V4!

To use the app, you'll need a compatible RTL-SDR such as the RTL-SDR Blog V3/V4, an Android Phone or Tablet with USB OTG support, and a USB-OTG adapter. 

The new V2.0 is a complete rewrite from scratch. Dennis notes the improvements to the app below.

The app has been completely rewritten from scratch. It now features a modern Material Design UI, a more powerful and intuitive interface, and improved performance across the board.

- Support for demodulation while app is in the background
- Improved stability, demodulation and recording features
- Integrated user manual and contextual help
- Added support for RTL-SDR Blog v4

The app is not free, but it is priced at only a few dollars, and there is a 7-day free trial with 60-minute time limit per session. The full feature list is shown below:

- Works with HackRF, RTL-SDR, or pre-recorded IQ files
- View live spectrum (FFT) and waterfall plots
- Demodulate AM, FM, SSB, and CW signals
- Record raw IQ samples for offline analysis
- A responsive and modern Material Design interface
- Scroll, zoom, and tune through the bands
- Built-in context-aware help and a full offline in-app manual

RF Analyzer V2.0 Running on an Android Mobile
RF Analyzer V2.0 Running on an Android Mobile
RF Analyzer V2.0 On a Tablet
RF Analyzer V2.0 On a Tablet

Dennis has also uploaded a video tutorial explaining how to use RF Analzyer V2.0, and there is a full online user manual available here.

RF Analyzer 2.0 - Quick Start Tutorial - Android SDR App

Amateur Weather Satellite Reception Beyond NOAA POES

With the recent decommissioning of NOAA POES (NOAA-15, NOAA-18, NOAA-19), many amateur weather satellite hobbyists might be asking themselves if the hobby is now dead.

While NOAA POES satellites were the easiest stepping stones into amateur weather satellite reception, the hobby has seen massive strides in enabling easier reception of other satellites over the past few years. Furthermore, in the near future, various new satellites are scheduled for launch, which should be receivable by amateurs.

Over on his blog, Jacopo has created a detailed post showing what satellites amateur hobbyists can still receive on the L-band and S-band. Some receivable satellites include Meteor-M,  Metop, Arctic Weather Satellite (AWS), STERNA, Elektro-L, GOES, EWS-G, Jason-3, UVSQSat-NG, DMSP, HINODE, ISS DATV and Proba 2.

While almost all of these satellites (apart from Meteor-M's LRPT 137 MHz signal) require a satellite dish and L-band, S-band, or X-band feed, recent products like our Discovery Dish can make setting up an L-band or S-band system significantly easier.

The Meteor-M series of satellites
The Meteor-M series of satellites

Moving SatDump Towards V2.0.0

Over on the SatDump blog developers Aang23 and Lego11 have recently uploaded a post discussing their plans to move SatDump towards Version 2.0.0. SatDump is currently the most comprehensive and popular software for SDR users wanting to decode images and data from satellites. 

The developers note that their update frequency has slowed down recently due to their focus on V2.0.0. The new version introduces significant under-the-hood changes that will make SatDump easier to manage and develop in the future, and also focuses on improved documentation.  

Users of SatDump will also see an improved GUI, new functionality such as crop, an SSTV decoder, support and improvements for a wide range of satellites, any many other improvements discussed in the post. 

We note that V2.0.0 has not yet been released. The post notes that at some point in the near future they will begin merging the new V2.0.0 branch into master, followed by frequency alpha releases, before finally releasing an official V2.0.0. 

SatDump V2.0.0 ALPHA with new GUI
SatDump V2.0.0 ALPHA with new GUI

RadioSport SDR: Portable Receiver Software for RTL-SDR

Thank you to Richard (9G5AR) for writing in and sharing with us a program he's developed called "RadioSport SDR". RadioSport SDR is a portable, no-install-required SDR program compatible with RTL-SDR devices. Richard writes that it is small and fast enough to be run off a USB stick.

The software supports demodulation of wideband FM, narrowband FM, AM, USB, and LSB modes. It also has a noise reduction feature.

The software can be downloaded from its GitHub release page here.

RadioSport SDR. Portable SDR Software for RTL-SDRs.

Saveitforparts: Receiving NOAA-15 One Last Time

Over on YouTube Gabe from the saveitforparts channel has uploaded a new video discussing the decommissioning of NOAA-15 and NOAA-19. We also previously posted about this topic a few days ago, if you are interested.

NOAA-15 was scheduled to shut down on August 12, 2025, but due to anomalies with NOAA-19, the decommissioning date of NOAA-15 has been extended by a few days until the week of August 18th. NOAA-19 has recently been experiencing transmitter failures, and it may be impossible to receive signals from it at the moment, despite its expected decommissioning date of August 19, 2025.

In the video, Gabe also rushes to try and receive signals from all transmitters on NOAA-15 one last time, setting up VHF, L-Band, and S-Band receivers. He experiences some issues with weak signals, interference, and recording failures, but ultimately succeeds in capturing all three signals during one of the final passes of NOAA-15.

US Government Shutting Down More Weather Satellites

Tech Minds: Testing out Discovery Dish for Inmarsat and Hydrogen Line Radio Astronomy

Over on YouTube Matt from the Tech Minds YouTube channel has recently uploaded a new video where he tests out our Discovery Dish antenna. Discovery Dish is designed to be a low-cost, portable solution for receiving L-band and S-band weather satellites, Inmarsat satellites, conducting amateur hydrogen line radio astronomy, and more.

In the video, Matt unboxes the Discovery Dish and provides an overview of the build process before demonstrating its use in decoding AERO and STD-C messages on Inmarsat. He then shows the dish and Inmarsat feed being used to receive Iridium satellites, and how they can be decoded using iridium-extractor with a HackRF or Airspy R2.

Finally, Matt swaps out the Inmarsat feed for the Hydrogen Line feed. Using SDR#, the IF AVG plugin, and Stellarium, he was able to obtain a clear hydrogen line peak.

This Discovery Dish Is The ONLY Satellite Dish You Will Need!

A Video Introduction to Broadband Surveillance with RTL_POWER

Over on YouTube "Mount Lethe Hellfire" has recently uploaded a video showing a deep dive into the rtl_power tool. rtl_power enables users to generate wide-spectrum displays by rapidly sweeping the RTL-SDR’s center frequency across the desired frequency range.

In this video I do a deep-dive into the command line tool, rtl_power, which is a purpose built headless RF broadband spectrum scanner. I dive into the command line, its use cases as it pertains to SIGINT (COMINT, ELINT), and finally do a live demo. Additionally, I provide some other ways to access your DragonOS running on Raspberry Pi with VSCode as well as troubleshooting issues with USB claims on Linux.

Broadband SIGINT Surveillance with RTL-SDR & rtl_power

In a second video, Mount Lethe Hellfire continues this topic and goes on to show how rtl_power can be combined with visualization and scripting for powerful RF spectrum analysis.

In this video I walk you through how to use a Python script (running on DragonOS, or otherwise) that will process rtl_power SSV outputs, normalize the data points, and assist you in visualization as well as local analysis using Structure Query Language (SQL) with DuckDB. The SQL analysis is to pull out the Top 10 frequencies sorted by dBm, nothing too crazy but enough to inform you on further ELINT and COMINT collection, processing, exploitation, and analysis efforts.

Analyze & Visualize RF Spectrum with rtl_power and Python scripting | ft. RTL-SDR