To install the Armbian Linux operating system Joseph used the instructions from i12bretro and installed OpenWebRX after. Then together with his RTL-SDR Blog V3 dongle he turned the device into a cheap dedicated WSPR (Weak Signal Propagation Reporter) monitor allowing him to free up his Raspberry Pi 3 which was used for the task previously.
IT9YBG's Android TV Box converted into a WSPR monitor with an RTL-SDR Blog V3 and OpenWebRX
In his latest video out on YouTube, Matt from the Tech Minds channel gives us an overview of GNU Radio, and shows a few examples of how it can be used to receive, transmit and decode digital data.
GNU Radio is a popular open source DSP framework for software defined radios. With it you can graphically implement any sort of digital signal processing chain that you like, which can be used for decoding/encoding and demodulating/modulating signals.
GNU Radio can be extremely complex and powerful, but in the video Matt shows some simple starter example flowgraphs like an LSB demodulator, and a simple wav file source transmitter for the HackRF.
How To Make Your Own SDR Software With GNU Radio Companion
With polar orbiting weather satellite reception we as amateur ground station operators with SDR receivers typically download images via "Direct Broadcast", which provides imagery of what the satellite is currently seeing live. However, the main way satellites such as the NOAA POES (NOAA 15, 18 & 19) satellites downlink is via "Global Area Coverage" (GAC) broadcast which provides the full stored imagery data of the entire global pass. However, GAC is only broadcast in locations where the satellite operator operates ground stations.
Over on YouTube dereksgc has uploaded a video showing how to receive GAC data from the NOAA POES satellites. He notes that GAC is now broadcast at 2247.5 MHz in the S-band, and the ground station it now downlinks to is likely in Svalbard, rather than in the USA. This means that amateur satellite stations close to the North Pole can receive the GAC signal, including dereksgc's station which (we believe) is in the Czech Republic.
Dereksgc uses a large 250cm offset dish with S-band feed connecting to a HackRF. In the video he demonstrates him receiving the signal, and then decoding it using SatDump. Finally he shows all the images from various locations around the earth that he was able to receive from one satellite pass.
Downloading stored data from NOAA weather satellites (GAC revisited) || Satellite reception pt.12B
Thank you to Ohan Smit (ZS1SCI) for submitting news that he has published his software called DATV-Red over on GitHub. The software is open source and is design to be an interface for controlling a PlutoSDR in Node-RED.
The PlutoSDR is a low cost RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range (with mods). Node-RED is a visual programming tool for creating JavaScript functions.
Ohan writes:
I've built an interface for controlling the plutosdr in Node-red.
It works on the latest PlutoDVB firmware.
It is cross platform since it is web based.
Currently the scope is focussed on QO-100 use, yet with the latest addition of the RX spectrum from the Pluto's onboard web socket, the focus would shift to a general spectrum analysis and RF operation with special operational DATV features
[It is] a work in progress.
DATV-Red: An interface for controlling the PlutoSDR in Node-RED
Over on the Tech Minds YouTube channel Matt has posted a video tutorial that shows how to build a cheap quarter wave ground plane antenna tuned for 1090 MHz. This is the frequency of ADS-B (Automatic Dependent Surveillance–Broadcast), which is a signal broadcast by aircraft that can be used to track their GPS location.
The antenna is created from an SMA chassis mount socket, one copper wire for the receiving element, and four copper wires for the ground plane. They are soldered directly onto the socket. An LNA is added to improve reception.
Make Your Own Aircraft Tracking Antenna With RTL SDR
Crowd Supply is hosting Teardown Session 38 on Thursday 3- November at Noon PST time which will feature the Discovery Dish. Join us for this livestream where I will be talking about and showing the Discovery Dish prototype.
Discovery Dish is currently being crowd funded over on Crowd Supply. It is designed to be an easy entry to the world of L-band weather satellites, hydrogen line radio astronomy, and Inmarsat reception. The Discovery Dish aims to be the start of an ecosystem of hardware designed to get users set up with satellite reception, including a planned companion light-duty antenna rotator.
Remember to click on the “Notify me” button on the YouTube link in order to be reminded about the stream!
Thank you to Mario A. Natali (I0NAA) who wrote in an wanted to share his Windows software called TotalPower which is designed for mapping the galactic Hydrogen line and works with RTL-SDR dongles.
The Hydrogen Line is an observable increase in RF power at 1420.4058 MHz which is created by Hydrogen atoms. It is most easily detected by pointing a directional antenna towards the Milky Way as there are many hydrogen atoms in our own galaxy. This effect can be used to measure the shape and other properties of our own galaxy.
Mario writes:
[TotalPower] was originally designed to measure total power of received spectrum and that, thanks to the input of many users, is now able to perform many other tasks including the 3D mapping of selected sky areas and HLine detection with the ability to estimate the speed of rotation of galaxy arms ( respect to our position )
People have had much success in receiving L-band weather satellites like GOES and polar orbiting HRPT satellites using 2.4 GHz WiFi grid dishes, even though their 1.7 GHz signals are considered out of band for the WiFi grid dish feed. While this works most of the time, reception can be sometimes weak and borderline.
António Pereira has also shared instructions for creating an antenna rotator from an ESP32, Arduino Nano, two NEMA 23 stepper motors, two stepper controllers, two 50:1 worm gearboxes, and two optical homing switches, as well as power supplies for the motors and circuits. He also shares the Arduino code that he's written.
We also note that we currently are crowd funding for our Discovery Dish, which will be a ready to use satellite dish system for L-band weather satellites, as well as Inmarsat and hydrogen line radio astronomy. Check it out on Crowd Supply.
Modified dipole feed on a 2.4 GHz WiFi grid antenna feedA DIY antenna rotator for the modified 1.7 GHz WiFi grid dish.
