Reports from Reddit and Twitter are in that the recently launched Meteor M2-2 weather satellite is now functional and broadcasting images at 137.9 MHz. A few people have noted that the reception quality appears to be better than the older satellite.
Thank you to Happysat whose also provided the following information that can be used to receive the images. It appears that a slightly modified version of LRPTDecoder is required:
This version of LRPTDecoder was used to test/debug OQPSK with Meteor M-N2-1 in 2014, it will work on Meteor M-N2-2. The ini file attached in the archive is processed manually from s files. Buttons 72K and 80K respectively for the modes “without interleaving” and “with interleaving”. Also in the archive there are examples for other modes.
Transmissions on LRPT with a OQPSK Modulation are expected tomorrow on most probably 137.900MHz.
On July 5 the Russian Meteor M N2-2 weather satellite was successfully launched into orbit and appears to be healthy. The LRPT weather camera signal is not yet broadcasting however, and we expect it to still take roughly 1-2 months before it begins (if all goes well) as satellites typically run through a long list of qualification tests before becoming operational. During this time there may be broadcasts of test patterns that can be caught. Meteor M N2-2 can currently be tracked in Orbitron and online at N2YO.
To try and dispel any confusion over the naming scheme, "Meteor M N2" is the currently operational LRPT satellite. "Meteor M N2-1" unfortunately failed in 2017 as it did not separate from the rocket. "Meteor M N2-2" is the new satellite which has just been successfully launched. Meteor M N2 and M N2-2 is often abbreviated as just "Meteor M2" and "Meteor M2-2". In the past there was Meteor M N1, but this satellite is no longer operational. We have upcoming launches for Meteor M2-3, M2-4, MP-1 and M3 to look forward to which are scheduled for 2020 and 2021.
Back on June 28 we posted about how Meteor M2 was experiencing orientation issues for a few days. Those issues appear to have been rectified now. Hopefully if M2 remains stable we'll have two Meteor LRPT weather satellites to receive alongside the three NOAA APT satellites.
If you're interested, there were also several other payloads onboard the rocket carrying M2-2, including a low cost Czech experimental cubesat called Lucky7 whose telemetry can be received in the amateur radio band at 437.525 MHz. There is an onboard camera too, but no details on how to receive it yet.
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 which could be multiple times a day.
Our standard NOAA weather satellite tutorial makes use of SDR#, audio piping and the WXtoIMG to receive NOAA satellite images. Martin's guide and software might be slightly easier for newbies as it only involves recording an audio WAV file, then loading it up into his software. The disadvantage is that the image is not colorized, and not displayed in real time as it is in WXtoIMG.
As you may already know, the old standard software in NOAA image decoding, WXtoIMG, is now considered abandonware, and the only place to get it is from a third party mirror rehosting the now defunct WXtoIMG website. As WXtoIMG is closed source no further development can occur on it. Martin's NOAA-APT still misses a lot of the advanced features of WXtoIMG but it is fully open source and multiplatform, and so it is a very promising program.
Receiving NOAA satellite images with noaa-apt and SDR#
COMS-1 is a geostationary weather satellited operated by the Korean Meteorological Agency (KMA) which was launched back in 2010. It is similar to NOAA GOES satellites as it is also geostationary orbit (@128.2°E - footprint covers all of Asia + AUS/NZ), and so is far away enough to image the entire disk of the Earth at once. Unfortunately, unlike the GOES satellites which have in the past few years become relatively easy for hobbyists to decode, the COMS-1 LRIT and HRIT downlink data is encrypted by KMA. KMA only appear to provide decryption keys to governments, research institutes and large organizations upon request.
However, recently Australian @sam210723 was able to successfully create code to decrypt the key message file and obtain the images. From a previous Twitter post of his, it appears that the encryption keys from the KMA example code are actually valid and can be used without needing to apply for a key.
Sam notes that he'll soon release a full blog post on his results, but for now he has an older post from last year that explains a bit about the satellite and decryption of the LRIT Key. His code is available on GitHub, and in a recent Twitter post he shows some example images that he's been able to receive using an Airspy SDR.
Recently Manuel (DO5TY aka Tysonpower from YouTube) wrote in and wanted to share his website that shows HRPT weather satellite receive stations from around the world on a map, and links to their Twitter pages where you can see the latest images that have been uploaded. The database also describes the SDR and antenna equipment used by each station. Currently there are 10 stations on the map, and Manuel encourages other people to submit their stations to the map database too. If you are interested in contributing your station to the map, please see Manuel's blog post for more information.
Since the satellite broadcasts a live image of what is currently being seen by the weather camera, each receiver location receives a live view of their part of the earth only. The end goal of Manuel's HRPT station map is to crowd source and collect multiple images of different parts of the earth to create a large HRPT composite image. In a previous post, Manuel who is based in Germany was able to create a beautiful composite image covering Germany, the Atlantic Ocean and Canada with the help of a station in Canada. With more contributors larger and more complete composite images of the Earth could be created.
HRPT is a high resolution weather satellite image signal that is broadcast from the same NOAA satellites that provide the more commonly received low resolution APT images at 137 MHz. HRPT is also broadcast from the Feng Yun and Metop-A satellites. However, HRPT transmits at 1.7 GHz, so a high gain dish antenna with motorized tracking mount, LNA and high bandwidth SDR like an Airspy is required to receive it.
USA-Satcom is the programmer of XRIT Decoder, which is a popular (paid) Windows decoding application for GOES weather satellites. With a WiFi grid dish antenna, LNA and SDRplay, Airspy or even an RTL-SDR, high resolution full disk images of the earth can be downloaded from these geosynchronous satellites. Browse through our previous GOES posts for ideas and various tutorials about setting up a receiver.
USA- Satcom has just released version 1.4.6985 of the XRIT Decoder software package. New features include:
1) Improved image clarity. 2) An antenna Align Mode feature. 3) And a Viterbi and Eb/No (Energy per Bit to Noise Power Spectral Density Ratio akanormalized SNR) graph over time feature.
The improved image clarity reduces image artifacts at the Earth-space boundary of the image and improves the overall aesthetics of the colorization of the full disk images. The images are quite amazing. The resolution is far better than what can be shown here due to image size limitations for this site. Below is a full disk GOES 16 image from February 17, 2019 and a corresponding zoomed in portion to get an idea of the resolution and clarity (the actual full disk images are approximately 40MB PNG images each which are much greater resolution than the below image)
The antenna Align Mode is a great new feature that allows users to view the Signal Quality, Viterbi FEC, and Eb/No from a distance using large numeric values. This mode enables users to better view these values when fine tuning adjustments to GOES receiving antennas. The Eb/No and Viterbi graphing enables users to see how well their receiving system is doing throughout the day (e.g., over temperature and while the sun is in alignment with the receiving path).
More updates from USA-Satcom to the XRIT Decoder software with a new patch from today. The XRIT file manager now provides IR image enhancements for GOES Bands 8 and 13. Here are some examples:
Last year in December we posted about Matt's element14 sponsored video which showed us how to create a portable briefcase contained NOAA satellite received based on a Raspberry Pi and RTL-SDR dongle. The build consisted of a heavy duty briefcase, modified ATX PSU and stripped down LCD monitor panel. This build resulted in a rugged and portable receiver. The full series of videos demonstrating the briefcase, ATX PSU conversion, LCD teardown, and NOAA satellite receiver demo can be found on his YouTube Playlist.
In his latest video Matt goes over the software installation procedure for creating an automated NOAA weather satellite receiver on the Raspberry Pi. He uses gpredict for predicting the satellite passes, and the Raspberry Pi version of WXtoImg for decoding the images. The rest of the video shows how to set up the software for your particular location, and how to set up decoding automation.
How To Set Up a Raspberry Pi as a NOAA Satellite Receiver with RTL-SDR
Thanks to "Lolo sdr" for submitting his videos that show his process for receiving and decoding Meteor M2 weather satellite images in Windows with an SDRplay and SDR-Console V3. Since the SDRplay is not supported by SDR#, it is not possible to use Vasilli's excellent Meteor Demodulator plugin (site in Russian, please use the Google Translate option) which is only available for SDR#.
Lolo's method gets around this limitation by initially recording an IQ file of the satellite pass in SDR-Console V3, then opening that IQ file in SDR# via the Fileplayer plugin, which is also by Vasilli and available here. The process is a bit of extra work, and the image isn't live, but the image comes out clearly in the end.
The videos are shown below, and subtitles are available in English, French and Italian via the YouTube player options.
Recibir y decodificar Satélite Meteor M2 con SDRplay, parte 1 de 2, grabar el pase, con subtitulos.
Recibir y decodificar Satélite Meteor M2 con SDRplay, parte 2 de 2, decodificar imagen y corrección.