Thank you to ON7NDR as well as CM2ESP for submitting and figuring out a way to get GOES 16 decoding working with RTL-SDR using the free XRITDecoder,Xrit2Pic software and GNU Radio for Windows.
ON7NDR's story is that he wanted to be able to receive GOES 16, but not being familiar with Linux he wanted a Windows based solution. He writes that the credit to finding the solution goes to CM2ESP who has written up a tutorial (pdf) explaining how to set everything up in Windows. ON7NDR has also written a separate complimentary tutorial (docx) that explains some steps in CM2ESPs tutorial a little further and provides a few tips on choosing correct the correct version of GNU Radio. He's also provided a screenshot showing what the correct config file looks like for an RTL-SDR dongle.
We note that for Windows there is also USA-Satcom's XRITDecoder, however this is closed source software which costs $100 USD.
Thank you to Neoklis (5B4AZ) for writing in and letting us know about his recently completed project which is a RTL-SDR compatible receiver and decoder application for the Meteor M2 weather satellite. It is a combination of other open source programs and he writes:
I combined the recently released Meteor-M2 LRPT demodulator by Davide Belloli (dbdexter-dev), and the older image decoder (translated to C) released by Artem Litvinovich (artlav), with relevant code from my own "sdrx" SDR Receiver application to create a complete monolithic Meteor-M2 Receiver and Image Decoder application, "glrpt".
Neoklis' glrpt application is available on his website www.5b4az.org under the "Weather Imaging -> Meteor M LRPT Receiver" menu. The application is open source and appears to be Linux only. In order to install it you'll need to download and compile the source code, and compilation instructions are available in the documentation stored in the doc folder. Neoklis also writes that you can find his older APT image decoder called "xwxapt" under the same Weather Imaging heading of his website.
GLRPT User Interface Showing Processed Meteor M2 Images
As promised we announced the release to KerberosSDR mailing list subscribers first, so that they'd be the first to get the initial discounted early bird units. However due to much higher than expected interest, we have released a few "second early bird" units at a still discounted price of $115 + shipping. We're only going to release 300 of these so get in quick before the price jumps up to $125. Our pre-order campaign will last 30 days, and afterwards the retail price will become $150.
If you weren't already aware, over the past few months we've been working with the engineering team at Othernet.is to create a 4x Coherent RTL-SDR that we're calling KerberosSDR. A coherent RTL-SDR allows you to perform interesting experiments such as RF direction finding, passive radar and beam forming. In conjunction with developer Tamas Peto, we have also had developed open source demo software for the board, which allows you to test direction finding and passive radar. The open source software also provides a good DSP base for extension.
KerberosSDR with Calibration Board Attached (Metal Enclosure with SMA connectors Not Shown)KerberosSDR Main Board (Metal Enclosure with SMA connectors Not Shown)
VOR stands for VHF Omnidirectional Range and is a way to help aircraft navigate by using fixed ground based beacons. The beacons are specially designed in such a way that the aircraft can use the beacon to determine a bearing towards the VOR transmitter. VOR beacons are found between 108 MHz and 117.95 MHz, and it's possible to view the raw signal in SDR#.
Over on RadioJitter author Arnav Mukhopadhyay has uploaded a post describing how to decode VOR into a bearing in real time using an RTL-SDR dongle. His post first explains how VOR works, and then goes on to show an experimental set up that he's created using a GNU Radio program. With the software he was able to decode an accurate bearing towards the VOR transmitter at a nearby airport.
Arnavs post is a preview of an academic paper that he's worked on, and the full paper and code is available by request on the radiojitter post. We've also seen on YouTube that Arnav has uploaded a video showing the software working in action, and we have embedded it below.
Bearing to nearby airport VOR transmitter determined with an RTL-SDR and GNU Radio.
Amazon Alexa is a smart speaker that can be programmed to control home automation devices via voice commands. For example, Stuart Hinson wanted to be able to control his wirelessly controlled blinds simply by verbally asking Alexa to close or open them. Stuart's blinds could already be controlled via a 433 MHz remote control, so he decided to replicate the control signals on an ESP8266 with 433 MHz transmitter, and interface that with Alexa. The ESP8266 is a cheap and small WiFi capable microchip which many people are using to create IoT devices.
Fortunately replicating the signal was quite easily as all he had to do was record the signal from the remote control with his RTL-SDR, and use the Universal Radio Hacker software to determine the binary bit string and modulation details. Once he had these details, he was able to program the ESP8266 to replicate the signal and transmit it via the 433 MHz transmitter. The remaining steps were all related to setting up an HTTP interface that Alexa could interface with.
If you're interested, we've also previously posted about another Alexa + RTL-SDR mashup which allows Alexa to read out ADS-B information about aircraft flying in your vicinity.
KerberosSDR is our upcoming low cost 4-tuner coherent RTL-SDR. With four antenna inputs it can be used as a standard array of four individual RTL-SDRs, or in coherent applications such as direction finding, passive radar and beam forming. More information can be found on the KerberosSDR main post. Please remember to sign up to our KerberosSDR mailing list on the main post or at the end of this post, as subscribers will receive a discount coupon valid for the first 100 pre-order sales. The list also helps us determine interest levels and how many units to produce.
In this post we're showing some more passive radar demos. The first video is a time lapse of aircraft coming in to land at a nearby airport. The setup consists of two DVB-T Yagi antennas, with KerberosSDR tuned to a DVB-T signal at 584 MHz. The reference antenna points towards a TV tower to the west, and the surveillance antenna points south. Two highlighted lines indicate roughly where reflections can be seen from within the beam width (not taking into account blockages from mountains, trees etc).
The second video shows a short time lapse of a circling helicopter captured by the passive radar. The helicopter did not show up on ADS-B. On the left are reflections from cars and in the middle you can see the helicopter's reflection moving around.
We are expecting to receive the final prototype of KerberosSDR within the next few weeks. If all is well we may begin taking pre-orders shortly after confirming the prototype.
Spektrum is a popular spectrum analyzer program that is used with RTL-SDR dongles. It is based on the command line rtl_power software and is compatible with both Windows and Linux. Thanks to it's easy to use GUI it is an excellent piece of software for scanning and determining where active signals exist, or for measuring filters and antenna SWR with a noise source.
Recently SV8ARJ (George) and SV1SGK (Nick) have been working on extending the original open source Spektrum code. Their improvements focus around the UI and making it more functional and easier to use. Currently the updated branch is in alpha, and they are hoping that any testers could help report bugs, issues and wishes to them. The code is available on their GitHub and the latest Windows test build can be downloaded from their DropBox.
The changelog reads:
2 Cursors for Frequency axis.
2 Cursors for Amplitude axis.
Absolute and differential measurements with cursors.
Zoom functionality of the cursors's defined area (gain + frequency).
Mouse Wheel Gain adjustment on graph (Top area for upper, low area for lower).
Mouse Wheel Frequency adjustment on graph (left area for lower frequency, right for upper).
Mouse Wheel in the centrer of the graph performs symetric zoom in/out.
View/settings store/recall (elementary "back" operation, nice for quick zoomed in graph inspection).
Right click positions primary cursors.
Right Double Click positions primary cursors and moves secondary out of the way.
Left Double Click zooms area defined by cursors (Amplitude + frequency).
Left Mouse Click and Drag on a cursor moves the cursor.
Middle (mouse wheel) Double Click resets full scale for Amplitude and Frequency.
Middle (mouse wheel) Click and Drag, moves the graph recalculating limits accordingly.
Reset buttons to Min/Max range next to Start and Stop frequency text boxes.
Cursor on/off checkbox now operate on all 4 cursors.
ZOOM and BACK buttons.
Filled-in graph option (line or area).
Display of frequency, Amplitude and differences for all cursors.
Modified: Button layout.
Fixed: Save/Reload settings on exit/start. IMPORTANT : delete the "data" folder from the installation location if you have it.
Thank you to Josh for submitting news about his project called GammaRF. GammaRF is an client-server program that is used to aggregate signal information via the internet from distributed SDRs. Currently the RTL-SDR and HackRF SDRs are supported.
ΓRF (“GammaRF”, or “GRF”) is a radio signal collection, storage, and analysis system based on inexpensive distributed nodes and a central server. Put another way, it is a distributed system for aggregating information about signals, and a back-end infrastructure for processing this collected information into coherent “products”.
Nodes utilize inexpensive hardware such as RTL-SDR and HackRF radios, and computers as small and inexpensive as Intel NUCs. Each node runs modules which provide various radio monitoring functionality, such as monitoring frequencies for “hits”, watching power levels, keeping track of aircraft (through ADS-B), and more. Nodes are distributed geographically and their data is combined on the server for hybrid analysis.
A web-based system allows users to view information from and about each station in its area. Below shows the server landing page. Markers are placed at each station’s last known location (stations can be mobile or stationary.)
GammaRF Server Landing Page
From the currently implemented modules it appears that you can monitor ADS-B, scan and monitor the power of a set of frequencies, forward the output from trunk-recorder (a P25 call recorder), scan the spectrum and monitor power levels, monitor a single frequency for activity, take a picture of a swath of RF spectrum, and collect 433 MHz ISM data. Some example applications might include:
Monitoring ham radio activity on repeaters in a city
Creating timelines of emergency services activity in an area
Distributed tracking of satellites and other mobile emitters
Monitoring power at a frequency, for example as a mobile node traverses an area (e.g. signal source location)
Building direction finding networks (e.g. for fox hunts)
Spectrum enumeration (finding channels and guessing modulation) [under development]
Monitoring Activity of an Amateur Radio Repeater via the 'scanner' Module
