Category: Satellite

NyanSat: A Low Cost Open Source Satellite Ground Station

Thank you to John D for writing in and letting us know that Wired magazine has recently run an article about the "Nyansat" project. Nyansat aims to bring low cost open source satellite ground stations to the masses. The goal is to democratize citizen access to space by allowing for easier collection of satellite data, or even for collaborative citizen science radio astronomy projects such as the detection of space debris or undocumented satellites. John writes:

While most people think of a satellite ground station as a giant dish mounted on top of a building in the desert, technically any radio receiver that tunes into a satellite's signal can be called a ground station.  Somewhere between the giant dish and the GPS chip in your phone is a ground station that uses a directional antenna to pull in the faint signals.  So unless you're only interested in geosynchronous satellites, the antenna needs to be aimed at the satellite, and that's where NyanSat comes in. 

The design of the NyanSat consists of a pan-tilt head, an Inertial Measurement Unit (IMU) for precise azimuth and elevation measurements, a motor-driver board, an optional OLED display, an optional GPS module, and is powered by an ESP32.  Full source code is available in their git repo, found at https://github.com/RedBalloonShenanigans/antenny. The NyanSat's software is written in micropython specifically for the ESP32, but obviously could be ported if desired.

Mounting an antenna, adding an RTL-SDR, and actually tuning in a satellite, is still up to the builder.

One of the goals of the NyanSat project is to eventually build up a network of ground stations that can collaborate to contribute frequently updated satellite ephemeris information.

When they're in stock, the project's sponsor, Red Balloon Security, has occasionally been offering a kit containing a custom PCB that is pre-populated with the ESP32 and motor driver; a pan-tilt gimbal; an IMU; and an RTL-SDR.  They've been selling them for $1.00(!), just to get them out in the hands of people.  Keep your eye open in case they get another batch in.

The Red Balloon store lists the kit as currently out of stock so we suggest keeping an eye on their store just in case any of the $1 kits come back in stock.

NyanSat will also present a live twitch demo at this years online DefCon conference on Friday Aug 7 6:30-8PM EDT and Sat Aug 8 6:30-8PM EDT. On Sun Aug 9 12:30 EDT they will hold another event where they judge the best work of the Nyansat community.

The SatNOGS project which we have covered many times before on this blog is quite similar with it's own open source antenna rotator design, however the Nyansat design looks a bit easier to build as it doesn't require 3D printed parts. Although critically from their demos we haven't seen what sort of sized antennas the gimbal chosen by Nyansat is capable of moving.

The NyanSat Pan/Tilt Gimbal Control Setup

TechMinds: Building a 3D Printed 2.4 GHz Dual Feed Helix for QO-100

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.

2.4 GHz Dual Feed Helix Antenna For QO100

Standalone Windows FengYun-3 & MetOp HRPT Weather Satellite Decoder

Back in June we posted about Alan (@aang254)'s work on porting the GNU Radio gr-hrpt decoder over to GNU Radio 3.8. More recently Alan wrote in and wanted to share the news that he has recently released standalone Windows decoders for the MetOp and FengYun-3 weather satellites.

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.

https://github.com/altillimity/Satellite-Decoders

A few images!

https://twitter.com/SamuelArmstro18/status/1285647473881513989
https://twitter.com/ZSztanga/status/1285277472284708865
https://www.reddit.com/r/amateursatellites/comments/hwhb7q/my_longest_fy3b_image_yet_i_got_up_at_430_in_the/
https://twitter.com/HA6NAB_Tomi/status/1285300023350222848
https://twitter.com/ub1qbj/status/1286734822820532224/photo/1

You can learn more about these satellites on USA-Satcom's Cyberspectrum talk and slides.

SignalsEverywhere: Decoding Digital Data via Audacity, Mulitmon-ng and MiniModem

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!

A Simple Guide to Setting up a DIY NOAA Weather Satellite Ground Station

A few weeks ago we posted about Sophie Dyer and Sasha Engelmann's work in creating an artistic performance based on weather satellite reception with SDRs. More recently they have uploaded their own tutorial showing how they receive NOAA APT weather satellite images with an SDR, turnstile antenna and computer. Sasha and Sophie note that they are attempting to create visually rich guides that don't assume any prior knowledge of radio, science or engineering.

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.

Receiving NOAA weather satellites
Receiving NOAA weather satellites

Step-by-step Guide to Creating a GNU Radio Based QO-100 SSB Receiver

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.

GNU-RADIO QO-100 SSB Receiver

Frugal Radio: 2020 SDR Guide Ep 1 – The Incredible World of Software Defined Radio (RTL-SDR, Airspy, SDRPlay etc.)

Frugal Radio has begun his YouTube channel a few weeks ago, and we've already posted about his YouLoop and SDR-Kits L-band patch antenna reviews as well as his results with the YouLoop on LF & VLF.

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 :
  • Using Free online SDRs
  • Comparison videos (eg Budget dongle shootout - Generic / RTL-SDR V3 / Nooelec SMARt v4)
  • "Must have" software guide
  • Antenna options and more

Users can view the channel at https://www.youtube.com/c/FrugalRadio or visit https://www.youtube.com/c/FrugalRadio?sub_confirmation=1 to subscribe directly.

If you're getting started with SDR, or are looking for new projects this might be a series to follow.

2020 SDR Guide Ep 1 : The Incredible World of Software Defined Radio (RTL-SDR, Airspy, SDRPlay etc.)

DragonOS: Decoding Iridium Satellites with the Iridium Toolkit and an RTL-SDR

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)