The Bullseye LNB that we have in our store is great for receiving the QO-100 amateur geostationary radio satellite which is available in some parts of the world. However it cannot be used to transmit to the satellite. Over on his YouTube channel Tech Minds shows us how to build a transmit helix antenna that connects to the Bullseye or other suitable LNB, resulting in a dual feed antenna.
The antenna that was built is based on DO8PAT's "Ice Cone Feed" design. The design requires some 3D printed parts for the mount and housing, as well as a copper wire helix, metal reflector and copper matching strip. The Bullseye fits onto the back of the helix mount. Once mounted on a dish Tech Minds shows that he was able to make contact with a friend via the QO-100 satellite with good signal strength.
MetOp and FengYun-3 are both polar orbiting satellites that beam back high resolution weather satellite images. Unlike the NOAA polar orbiting satellites which transmit both the easy to receive APT and more advanced HRPT signal, these only transmit a HRPT signal at ~1.70 GHz, so a satellite dish and motorized tracking mount (or hand tracked) is required. You will also need an SDR capable of receiving over 3 MHz bandwidth such as an Airspy Mini or R2. Alan writes:
I recently got FengYun decoding working after the release of my MetOp decoder a while ago. Since gr-hrpt wasn't usable for Windows user without some major hassle, I made some standalone decoders (Windows builds included in the repo) for both MetOp and FengYun.
Decoding is done by first demodulating with the included flowcharts or @petermeteor's, then processed through the decoder which does Viterbi / Differential decoding. The output then needs to be deframed by MetFy3x or any other software that can do so.
SignalsEverywhere is back this week and in her latest video Sarah talks about using a combination of Audacity, Minimodem and Multimon-ng to decode digital data that could be obtained from an SDR or other signal source.
Sarah was interested in the 2020 Hackasat space security challenge and specifically in completing the 56k Flex Magic challenge which consists of an emulated signal from an old 56k modem. Within the 56k modem signal is secret information required to complete the challenge.
Sarah first shows how to use Multimon-ng to decode the DTMF tone section of the signal. These are the tones heard when dialling on a landline phone. She then goes on to show how to use Audacity in spectrogram mode to take a closer look and analyze the next chunk of the signal. Then by using the information gained about the signal from the spectrogram analysis she is able to decode the data via minimodem.
Audacity Decoding Data?! Using Audacity Multimon-ng and Minimodem to Decode Digital Audio Data!
From Sasha's Twitter feed we note that they are also working on upcoming public workshops in the UK and Germany on the topic of reflections on what it means to bring an intersectional feminist ethos to satellite image decoding + weather sensing, & new creative collaborations in 2020. If you are interested in their work please follow @sashacakes and @sophiecdyer on Twitter.
Thank you to M Khanfar for submitting his video that shows a step-by-step tutorial on building your own SSB receiver in Windows GNU Radio for QO-100 satellite reception. His tutorial includes adding several tuning sliders in the GNU Radio GUI as well.
QO-100 / Es'hail-2 is a geostationary satellite at at 25.5°E (covering Africa, Europe, the Middle East, India, eastern Brazil and the west half of Russia/Asia) providing broadcasting services. However, as a bonus it has allowed amateur radio operators to use a spare transponder. Uplink is at 2.4 GHz and downlink is at 10.5 GHz. We note that we are selling a "bullseye" LNB in our store which allows most SDR dongles to be able to receive the signal with high frequency accuracy.
He's now begun a new series on his channel where he will be exploring the world of software defined radio in more depth. The first video that he's uploaded today is an overview where he overviews EMS communications, aircraft signals, military air signals, maritime signals, space signals, as well as other interesting signals he's received like wireless earpieces for musicians at concerts and TV studio talkback links. He writes:
The 2020 SDR Guide Episode 1 has just been released. It serves as an introduction to the incredible world of Software Defined Radio and will be of interest to both beginners and more advanced users.
Over the next few weeks, Frugal Radio will be exploring various aspects of using SDRs within the hobby. These include :
DragonOS is a ready to use Linux OS image that includes various SDR programs preinstalled and ready to use. The creator Aaron also runs a YouTube channel that has multiple tutorial videos demonstrating software built into DragonOS.
In his latest video Aaron explores Iridium reception with an RTL-SDR Blog V3, RTL-SDR Blog Active L-Band Patch Antenna and Iridium Toolkit/gr-iridium. Iridium is a satellite constellation that provides services such as global paging, satellite phones, tracking and fleet management services, as well as services for emergency, aircraft, maritime and covert operations too.
In the video he shows how to edit the config file to turn the bias tee on, how to record Iridium data, how to install the AMBE voice decoder, and finally how to decode the Iridum data with Iridium toolkit and play voice recordings.
DragonOS LTS Decoding Iridium satellites with the Iridium toolkit (gr-iridium, RTL-SDR)
Just after our post a few days ago about an art project involving weather satellite reception with SDRs, we received a story submission about an artistic performance with similar weather satellite and SDR themes. The submission from Sasha Engelmann reads:
Open Work, Second Body asks: From the climate crisis to coronavirus: what are the tools we need to make sense of events unfolding on vastly disparate scales? Through spoken word, field recordings and live radio reception of two NOAA satellite images, the work probes the porous boundaries between our bodies, local atmospheres and weather systems.
Due to lockdown constraints in London, Sophie and Sasha were not able to be in the same place or to leave their apartments, so they performed the work via simultaneous streams from their respective balconies in South East and North West London. Using RTL-SDRs, Turnstile antennas, Open Broadcast Software and collaborating with two NOAA satellite passes, Sophie and Sasha shared the process of decoding NOAA satellite images with hundreds of viewers around the world, employing spoken word poetry and field recordings to complicate relationships of local and global, weather and climate, the individual and the collective.
Recordings of the performances can be found at the links below.
Open Work, Second Body is part of Sophie and Sasha's larger artistic research and design project Open Weather, which employs ham radio, open data and feminist theories and approaches to build new and diverse communities around satellite image decoding and weather sensing. The Open Weather web platform will be launched in Summer 2020 and will host an archive of SDR-generated weather images, visually rich how-to guides for those with no radio and engineering experience, and material about Sophie and Sasha's collaborative artistic practice.
For Open Work, Second Body, Sophie and Sasha would like to thank the Soundcamp Team: Grant Smith, Dawn Scarfe, Christine Bramwell, Maria Papadomanolaki and Ciara Drew. They are grateful to Daisy Hildyard for her willingness to be in conversation with them, Bill Liles NQ6Zfor technical advice, Jol Thoms for sound design, Rachel Dedman, Laure Selys and Arjuna Neuman (Radio Earth Hold) for early curatorial input, Akademie Schloss Solitude for the support of a residency, the satellites NOAA 18 and NOAA 19 and the RTL-SDR and wider ham radio community.