Last week we posted about M Khanfar's YouTube video that showed how to decode Es'Hail-2/QO-100 DVB-S2 on Ubuntu with the LeanDVB decoder. However, the method he showed was not in real time as it involved recording an IQ file in GQRX first, then decoding that IQ file. Similarly we also posted last week about a Windows based real time decoder.
M Khanfar recently wrote in again and wanted to show that real time decoding is possible with LeanDVB. The method is to simply pipe the output of the rtl_sdr command line decoder in LeanDVB, and then into VLC. He notes that his PC isn't actually fast enough to decode in real time without lag, but a modern i5 CPU would work well. The actual terminal command is shown in his YouTube video description.
This is Realtime live DVB-S2 Decoding done , without need to record .RAW file , its live and easy method by one click ! In this video i decoding 2MS symbol rate from wideband transponder of QO-100 beacon , you can decoding 1MS , 0.5MS , 333KS , 125KS symbol rate ! The lower Symbol, the faster speed for decoding! , the Amateurs operators on QO-100 Uplink DATV DVB-S2 at 0.5 , 333 , 125Ks , so its easy to Live Decoding Now ! With very low SNR ! , so the normal SDR can coverage wideband beacon of 2Ms symbol and all Ham uplink ! , if you have an SDR that can coverage 27.5 mb of bandwidth, so you can easy decoding Live a standard commercial satellite channels! But it need a high speed Pc .
Yesterday we posted about a real time Windows demodulator for receiving amateur TV DVB-S/S2 on Es'Hail-2/QO-100. Recently another YouTube user "M Khanfar" also submitted a video tutorial showing how to decode Es'Hail-2 DVB-S2 on Ubuntu with an RTL-SDR and the LeanDVB decoder.
Khanfar notes that although the LeanDVB decoding method is not real time, his tests show that the LeanDVB method is able to work with a much lower SNR signal compared to the Windows demodulator. The process is to simply capture an IQ file with GQRX, then run LeanDVB on the command line with the recorded IQ file. It will create a TS file that can be played in any media player.
His receiving setup consists of an RTL-SDR, 100cm dish, modified LNB and a home made bias tee that can switch his LNB between horizontal and vertical polarization.
Thank you to Happysat for writing in and noting that over on the Amsat-DL forums user Markro92 has uploaded a realtime Windows DVB-S demodulator with GUI. The demodulator works with the RTL-SDR, HackRF, SDRplay and PlutoSDR support is due to be added soon. Happysat notes the following:
It can demodulate DVB-S and S2 signals with very low symbolrate on Es Hail-2 geosat on 25,9 East from the Wideband Transponder. So you do not need a modified lnb or modified satelitte stb :) Of course you can also see the amateur tv streams which people uplink theirself.
To see if there is any stream active one can visit the wideband WebSDR and above the stream the info is displayed which parameters in use (symbol rate and mode dvbs(2)) so you can adjust in the Demodulator program. Stream + Chat: https://eshail.batc.org.uk/wb/ .
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.
HackSpace is a monthly magazine dedicated to modern maker projects. This month issue 18 was released and it focuses on space based projects. The HackSpace Magazine is available for free online in PDF form, and physical copies can also be purchased. There are several interesting articles but one in particular shows us how to set up a SatNOGS ground station with a Raspberry Pi 3, RTL-SDR and a satellite antenna such as a turnstile.
A problem with low cost satellites like cubesats is that it is difficult to monitor them as data can only be collected when they are passing over a ground station. So in areas with no ground stations data is simply lost. SatNOGS is an open source project that aims to make it easy for volunteers to build and run RF ground stations that automatically monitor satellite data, and upload that data to the internet for public access. SatNOGS ground stations typically use RTL-SDR dongles as the radio.
A related article in the magazine also discusses cubesats, giving an overview of some previous cubesat launches and what sort of payloads are available. A third article under the space topic discusses the Libre Space Foundation which is the team behind the SatNOGS and various other space based projects that aim to democratize space. Readers may also be interested in the articles showing how to build an ISS countdown timer and how to build a Slim Jim antenna.
If you weren't already aware, the Othernet project aims to bring live data such as news, weather, video, books, Wikipedia articles and audio broadcasts to the world via a free satellite service and cheap receivers. Although an internet connection provides the same data, Othernet's satellite broadcast is receivable in remote areas, will continue working in disasters, and costs nothing to continually receive roughly 200MB of data a day. The trade off is that the service is downlink only, so the data that you get is only what is curated by the Othernet team.
Currently the public service is in a test period and is only available in North America. Europe has come online recently too, however they write that the current version of Dreamcatcher that is for sale may not be optimal for receiving the EU signal.
While currently active, they write that the Othernet satellite service is not guaranteed to continue long term. However even if the service discontinues, the Dreamcatcher can still be used as a TX/RX capable LoRa radio. In a previous post we demonstrated a fun application with two Dreamcatchers and a LoRa chat application.
Over on YouTube Tech Minds has posted a video explaining what Es'hail-2 satellite is and why it is interesting for hams and SDR users. Briefly Es'hail-2 is a recently launched geostationary TV satellite that covers Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia.
What's special about it is that apart from the TV transmitters, it also contains the worlds first amateur radio transponder in geostationary orbit. So amateur radio users within the region covered by the satellite can simply point their antennas to a fixed position in the sky to transmit to the satellite, and the signal will be rebroadcast over the entire covered area. With a simple LNB, satellite dish and SDR the signals can be received.
After explaining Es'hail-2 Tech Minds also shows a demo of Es'hail-2 radio traffic using a public WebSDR.
The Worlds First Geostationary Satellite For Ham Radio - Es'Hail 2 - Qatar OSCAR-100
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: