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
Aleksey Smolenchuk (lxe) has recently uploaded a step-by-step guide to setting up a GOES weather satellite receiver with an RTL-SDR dongle, Raspberry Pi and the goestools software. GOES 15/16/17 are geosynchronous weather satellites that beam high resolution weather images and data. In particular they send beautiful 'full disk' images which show one side of the entire earth. Compared to the more familiar and easier to receive low earth orbit satellites such as NOAA APT and Meteor M2 LRPT, the geosynchronous GOES satellites require slightly more effort as you need to set up a dish antenna, use a special LNA, and install Linux software.
Aleksey's tutorial first shows where to purchase the required hardware and notes that the total cost of the system is around $185. Next he goes on to show the hardware connection order, and then how to install and configure the goestools decoding software onto a Raspberry Pi.
On The Thought Emporium YouTube channel a new video has been uploaded showing the full disk images of the earth that they've been able to receive from GOES geosynchronous weather satellites. Over the past couple of years GOES satellite reception has become much easier for hobbyists to achieve with the release of the NooElec SAWbird LNA+Filter, information on how to use a cheap 2.4 GHz WiFi grid antenna for reception and the release of free open source decoder software. It was also shown that an RTL-SDR dongle is sufficient for receiving these images as well. With all these new developments it is now possible to build a GOES receiving station for under $100.
The Thought Emporium video blurb reads:
In the fall of 2016 I saw my first rocket launch and little did I know that the satellite on that rocket would come to shape and fill my thoughts for many years. We're no strangers to getting data out of space on this channel, but GOES-16 is special, and not just because I was there when it left earth. Unlike the satellites we looked at in the past, GOES is in geostationary orbit and has an amazing suite of cameras and sensors on board. While it's a bit harder to receive data from GOES the extra effort is absolutely worth it, especially because it can see then entire globe all at once and send out those images in stunning high resolution. And it even comes with the added bonus of rebroadcast data from other satellites giving us a view of the opposite side of the planet as well.
In this video we go through the hardware and software needed to receive these gorgeous images and what is contained in the signals we receive.
Pulling Clear Images Directly Off Satellites | GOES-15,16,17 and Himawari 8 HRIT
Over the last few months Lucas Teske (author of the Open Satellite Project) has been working on a piece of software called "SegDSP". The idea appears to create a web GUI based SDR receiver for SpyServer streams which can be used to create a cloud of channel demodulators, essentially segmenting the DSP computation burden over multiple computers.
SpyServer is a SDR server application that is compatible with Airspy products and RTL-SDRs. It allows you to connect to these SDRs remotely over a network or internet connection. The SDR server computer sends the radio IQ data over the network allowing you to perform processing remotely. A major advantage of SpyServer compared to other SDR server applications is that it only sends the raw IQ data for the portion of the spectrum that you're interested in which can save a lot of bandwidth.
One key application that Lucas envisions for SegDSP is using it with cloud clusters of single board computers (SBC) like the Raspberry Pi 3. The philosophy is that there will be specific roles for each SBC machine. For example you might have some SDR machines running SpyServers, some processing machines for demodulating and decoding multiple channels, and a storage machine for recording data. Then you can dynamically spawn / despawn workers when needed (for example only spawning a machine when a LEO satellite with data to decode passes over).
SegDSP development is still in the early stages, and appears to only have the web GUI set up at the moment with a few demodulators. But keep an eye on his Twitter @lucasteske for updates too. Lucas also did a talk at the last CyberSpectrum meetup. His talk can be found at 1:30:00 in the recording.
Microp11, the programmer of Scytale-C a standalone Inmarsat decoder has just released a new Inmarsat decoder SDR# plugin. The plugin is currently in the "pre-alpha" stages, so is still missing some functionality and may be buggy. However, it does appear to be functional at this point in time. It can be used with RTL-SDRs, and any other SDR# compatible SDR including units running on remote SpyServers. Microp11 writes:
I ran it with SDR# version v1.0.0.1761.
If it crashes you SDR# I apologize in advance.
The auto-tracking (default on) will alter your SDR# frequency and follow the signal’s CF. When the SNR is very low, please disable it and manually tune the SDR# to try to get the CF as close to 2000 as possible.The demodulator still has plenty ideas of its own.
Use USB mode with 4000 Hz bandwidth.
For now the interface is missing the usual scatter plots.
UDP Address and UDP Port are for sending the decoded frames to the Scytale-C UI.
Offset and CF are the difference from zero error and the CF frequency of the demodulated BPSK signal.
Tx and SYM are the transmitted over UDP frames and SYM is showing the number of demodulated symbols.
A bunch of libraries are attached as extra files. Please be gentle and accept the package as it. Will clean-up in the future.
Use in conjunction with the Scytale-C UI from the archive: “x64-UI1.6-Decoder1.4.zip” (link below)
The magic line is included in the archive: “SDRSharp.ScytaleC-1.0-alpha.zip”
NooElec has just released their new "SAWbird" GOES LNA for sale. This is an LNA and filter combination designed to help receive GOES weather satellite images. On the PCB is a 1688 MHz SAW filter and a low noise amplifier. It can be powered with 3V - 5.5V connected directly or via bias tee. The SAWbird is currently available on Amazon and their store for US$34.95. They also have a version for Inmarsat and Iridium, so make sure you choose the correct one.
GOES 15/16/17 are geosynchronous weather satellites that beam high resolution weather images and data. In particular they send beautiful 'full disk' images which show one side of the entire earth. As GOES satellites are in a geosynchronous orbit, the satellite is in the same position in the sky all the time, so no tracking hardware is required and images can be constantly pulled down throughout the day without having to wait for a satellite to pass over.
However, compared to the more familiar and easier to receive low earth orbit satellites such as NOAA APT and Meteor M2 LRPT, geosynchronous satellites like GOES are quite a bit further away, and transmit at 1.7 GHz. So to receive the signal you'll need a dish antenna that you can accurately point, a good low noise figure LNA and possibly a filter. So setting up a receiver is a bit more difficult when compared to receivers for NOAA and Meteor satellites. The SAWbird should help however, by providing a ready to use LNA+Filter combination.
Over the past few months several testers have already received engineering samples of the SAWbird and have been successful at receiving GOES images. From the results of several experimenters, it appears to be possible to use a cheap 2.4 GHz WiFi grid antenna with some minor modifications as a GOES satellite antenna. Get one with at least a one meter long width and bend the feed as described here or here to tune reception for the 1.7 GHz GOES frequency. Pieter Noordhuis has also shown that it's possible to use an RTL-SDR to receive GOES images, so an entire GOES system can be built on a budget.
NooElec SAWbird LNA + Filter for GOES reception.GOES Full Disk Image of the Earth
Over on GitHub user martinber has released a new NOAA APT image decoder that can run on both Linux and Windows. The decoder is called noaa-apt and takes a .WAV file of a NOAA satellite pass, and turns it into an image file. The .WAV file can be recorded in any SDR program like SDR#, HDSDR, GQRX etc. The program is programmed in Rust, and has ready to run binaries available for both Linux and Windows available on it's GitHub Releases page.
Compared to the features found in WXtoIMG the software is fairly basic, but as WXtoIMG has been abandoned it's good to see new APT decoders still being worked on. The software can also be used to simply resample the .WAV file into a sample rate required by other more featured decoders like aptdec.
NOAA weather satellites broadcast an Automatic Picture Transmission (APT) signal, which contains a live weather image of your area. With an RTL-SDR and antenna they can be received and downloaded every time one of the satellite's passes overhead. We have a tutorial on using an RTL-SDR with WXtoIMG available here.
