Over on YouTube channel "Privacy & Tech Tips" has uploaded a video demonstrating how it's possible to run GQRX with an RTL-SDR on a PinePhone. In the video the presenter shows how to set up the screen so that GQRX is fully visible, demonstrates GQRX running, and then goes on to show exactly how to install the RTL-SDR drivers on the PinePhone.
The PinePhone is an open source smart phone that can run a full Linux distribution. A PinePhone sells for US$149.99 or $199.99 for a higher end version with more RAM and storage.
RTL-SDR On The Pinephone! Demo, Installation/Hardware
There are already many image decoders for the NOAA APT weather satellites available, with the most common and feature rich program being the abandoned freeware "WXtoIMG".
However many people may not know how simple the APT digital signal processing code is. Over on his blog post Dmitrii Eliuseev explains how only 50 lines of Python code are required to decode an image from received APT audio. Dmitrii's post shows how a Hilbert transform is used on the APT audio which is essentially the entire decoding step. This is then followed by a for loop that calculates the pixel luminosity from the decoded data, and plots it onto an image file.
Of course the image is only grayscale (or in Dmitrii's case he decided to use greenscale), but adding false color and various other image enhancements found in advanced software like WXtoIMG are just standard image processing techniques.
Dmitrii concludes with the following:
Interesting to mention, that there are not so many operational radio communication systems in the world, the signal of which can be decoded using 20 lines of code. The NOAA satellites are about 20 years old, and when they finally will retire, the new ones will most likely be digital and format will be much more complex (the new Russian Meteor-M2 satellite is already transmitting digital data at 137 MHz). So those who want to try something simple to decode can be advised to hurry up.
Over on GitHub stdevPavelmc has released his software called FAASGS (Fully Automatic Amateur Satellite Ground Station). FAASGS is an open source program that allows RTL-SDR users to set up a satellite ground station that tunes, record and generate images for NOAA APT weather satellites, as well as records FM amateur radio satellites. The software runs on a single board computer such as a Raspberry Pi, however in the authors own setup he uses an Orange Pi Prime board. The features include:
Web interface to see the next passes, the recorded ones, and details for it.
Receive any satellite in FM mode (SSB is possible but no there is doppler control yet, so no SSB by now)
Record the satellite pass and keep the audio for later.
APT WX audio is preserved in wav format and 22050 hz of sampling (the format wximage needs to work with)
FM audio satellites is preserved in .mp3 mode but with high quality settings, and other tricks.
The spectrogram of the audio is embedded as album art (see below).
The pass data and receiving station are stored in the mp3 tags.
Automatic decode APT images from WX sats (NOAA 15, 18 and 19)
For the voice FM sats we craft a spectrogram and embedd the metadata of the pass on the image
FAASGS main screen showing recordingsFAASGS screen showing an FM amateur radio satellite pass
DragonOS is a ready to use Ubuntu Linux image that comes preinstalled with multiple SDR program. The creator of DragonOS, Aaron, uploads various YouTube tutorials showing how to use some of the preinstalled software. This month one of his tutorials covers how to use a SDRplay RSP1A or a HackRF to receive and decode FT8 with the preinstalled software WSJT-X or JS8Call. Aaron also notes that an RTL-SDR could also be used as the SDR.
In the video he covers how to set up a virtual audio cable sink in Linux for getting audio from GQRX into WSJT-X, setting up rigctld to allow WSJT-X to control GQRX, configuring GQRX, CubicSDR and WSJT-X, and finally downloading and using GridTracker.
In this weeks video Sarah from the SignalsEverywhere YouTube channel show us how to install and configure the OP25 software on a Linux machine. OP25 is a Linux based P25 digital voice decoder which works with RTL-SDR dongles. It is capable of decoding both Phase 1 and Phase 2 systems. Installation is fairly simple via an installation script, but it does take some time to install. After installation Sarah shows how to configure the software in order to properly follow a trunked P25 system. In order to help with importing talkgroup information from a premium RadioReference account Sarah has also created an automatic importer Python script which is very useful.
OP25 Installation and Configuration Tutorial | Setup OP25 P25 Phase 1 and 2 SDR Decoder on Linux Pi
GNU Radio is an open source digital signal processing (DSP) toolkit which is often used in cutting edge radio applications and research to implement decoders, demodulators and various SDR algorithms. Version 3.9.0.0 has recently been released. Below is part of the release text, but please see the official release post for the full list of changes.
The future is not set, there is no fate but what we make for ourselves. In this very spirit, GNU Radio 3.9 packs a whole bunch of power when it comes to transforming the way GNU Radio and its ecosytem can be developed in the future.
Not only did we have great progressions from old dependencies that proved to be all too problematic (SWIG, Python2), but also did we see an incredibly influx of people actively working on how maintainable this code base is. This will nurture the project for years to come.
All in all, the main breaking change for pure GRC users will consist in a few changed blocks – an incredible feat, considering the amount of shift under the hood.
GNU Radio 3.9.0.0 is out!
This significant release is focused on maintainability and code consistency, and has many new GUI elements (LED indicators, compass, Az/El plot, toggles and more!), new DSP blocks, and a variety of enhancements and fixes.https://t.co/SIpqRQuiIF
Over on YouTube "River's Educational Channel" has uploaded a video showing how he was able to reverse engineer the wireless control signal from his ceiling fan remote, and use that information to create a new transmitter controlled via his smart home's Raspberry Pi.
In the video River uses an RTL-SDR and the Spektrum software to initially identify the remotes frequency, before moving on to record the signal in Universal Radio Hacker (URH). He then goes on to reverse engineer the signal and determine the binary control string for each button on the ceiling fan's remote control.
In part 2 which is yet to be released River will show how to transmit this signal via his Raspberry Pi 3B in order to integrate it with his smart home.
Hacking My Ceiling Fan Radio Signal With a $15 USB TV Tuner (RTL2832U)
Back in November 2020 we posted about the release of a decoder for the FengYun line of geostationary weather satellites which provide full disk images of the Earth and are positioned to cover parts of Europe, Africa, the Middle East, Asia, Russia, and Australia. Back then only a few people had attempted decoding this, and it was believed that a 120cm satellite dish or larger would be required.
We do note that u/Harrison_Clark55's image appears to be missing a few lines of data, and they are based in Australia where the elevation of FY-2G could be quite high depending on what side of the continent they are on. So it's possible that receivers in lower elevations may still require a larger dish size to work.
Full Disk FY-2G image received by u/Harrison_Clark55 (see the Reddit post for full resolution image)
