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.
Recently we posted about bladeRF-wiphy which is open source code that can turn a bladeRF software defined radio into a software defined WiFi access point. The bladeRF 2.0 is a relatively low cost SDR which costs $420 for the low end version. It is capable of both transmit and receive (2x2 MIMO) with a 47 MHz to 6 GHz frequency range and 61.44 MHz sampling rate.
Over on YouTube Aaron who created DragonOS has uploaded a video demonstrating bladeRF-wiphy in action. He writes:
This video demonstrates Nuand’s new open source 802.11 modem/FPGA available for the bladeRFxA9. Everything will be Pre included in DragonOS Focal to setup an open AP and hopefully whatever’s required for use within Kismet.
Minor configuration is needed for the open AP, while Kismet integration should be pretty straight forward.
This is an awesome addition to the bladeRF and I look forward to seeing what else is possible with this new open source 802.11 compatible modem!
DragonOS Focal BladeRF-wiphy w/ Open Wi-Fi AP and Splash page (bladeRFxA9)
Back in August 2020 we posted about OpenWiFi , an open source implementation of the full IEEE802.11/Wi-Fi stack for FPGA and SDR combo board. Recently the team at Nuand have released their own WiFi implementation called "bladeRF-wiphy" for their bladeRF 2.0 software defined radio. The code is implemented in VHDL, which runs directly on the bladeRF's on board micro xA9 FPGA.
The bladeRF-wiphy project is an open-source IEEE 802.11 compatible software defined radio VHDL modem. The modem is able to modulate and demodulate 802.11 packets (the protocol WiFi is based on), and run directly on the bladeRF 2.0 micro xA9’s FPGA.
The bladeRF-wiphy coupled with Linux mac80211 allows the bladeRF 2.0 micro xA9 to become a software defined radio 802.11 access point! 802.11 packets (PDUs) are modulated and demodulated directly on the FPGA, so only 802.11 packets are transferred between the FPGA and libbladeRF.
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
We recently came across a relatively new SDR design that is called "TinySDR". The design is entirely open source and is focused on helping analyze wireless Internet of Things (IoT) applications. Currently the device is not manufactured and sold by anyone, but the open source Altium Designer PCB files, BOM and firmware can be found on their GitHub.
Over on hackster.io Tom Fleet has also given the TinySDR a writeup. He notes that the design is based around the AT86RF215 transceiver chip and a Lattice Semiconductor ECP5 FPGA. The board is split into an input for 2.4 GHz and a sub-GHz input. On the GitHub there are currently demo files available to turn the SDR into LoRa and FSK modulators.
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
