SatDump Version 1.1.0 Released – Feature Overview

SatDump is a popular program that can be used with RTL-SDRs and other software defined radios for decoding images from a wide array of weather imaging (and other) satellites including GOES, GK-2A, NOAA APT, NOAA HRPT, FengYun, Electro-L and Meteor M2 LRPT + HRPT, and many many others. It is multiplatform, running on Windows, MacOS, Linux and even Android. Because of it's good decoding performance, wide satellite and OS compatibility, it is the most recommended software for satellite decoding.

Recently SatDump was updated to version 1.1.0 and the new version brings many enhancements and new features. In summary, Lua scripting support has been added, calibrated products are now possible, composites can be made via Lua scripting, nightly builds are now available on GitHub, Mac .dmg builds are now available, decimation has been added, an SDR Server is available, and a Windows installer was added.

Support for various satellites and their instruments have also been added for NOAA APT, CCSDS LDPC decoding for Orion, LandSat-9, TUBIN X-Band, FengYun-3G/3F, Meteor M2-3, Geonetcast (soon), GOES RAW X-Band,  STEREO-A, DSCOVR EPIC, ELEKTRO-L N°4, Inmarsat STD-C, UmKA-1 (soon), PROBA-V GPS .

SatDump also now includes rotor tracking control which works together with it's satellite pass predictor and scheduler. There is no more need to use programs like Orbitron or Gpredict as everything can be handled by SatDump.

An insane amount of work has gone into SatDump, so if you like the software please remember to support the developer @aang23 by donating on Ko-Fi.

SatDump Rotator controller, Tracker and Scheduler
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M2_LRPT_DECODER Version 59 Released

Thank you to Carl Reinemann for writing in and sharing with us that the Meteor M2 LRPT decoder by Oleg (Robonuka) was recently updated. The Russian Meteor M2-3 weather  satellite was launched in June of this year and is currently the only operational Meteor M2 satellite in the sky. It transmits images at 137 MHz in the digital LRPT format.

To receive it a simple V-Dipole antenna and RTL-SDR is usually sufficient. And to decode it software like SatDump or M2_LRPT_DECODER combined with the Meteor Demodulation Plugin for SDR# can be used. Instructions for the latter are available on HappySats instructional page.

Regarding the update Carl writes:

Thanks to Oleg (Robonuka), Happysat and Usradioguy have been testing the new decoder for about 6 weeks now, and it is ready to go!

  • The stability of the processing has been improved: The decoder is now more likely to produce stable results, even when there are errors in the input data.
  • The procedure for generating RGB and calculating GEO in the error-handling block has been improved. Now, the decoder's processing is considered unfinished until the GEO calculation is completed.: This means that the decoder will now wait until the GEO calculation is finished before generating the RGB values. This helps to prevent errors and produce more accurate results.

  • Exception errors fixed: Some errors that were previously causing the decoder to crash have been fixed.

  • AutoClose=yes by default: This means that the decoder will now automatically close when it is finished decoding. This can be helpful for saving resources and preventing memory leaks.

  • 80K is much more stable: The decoder is now more stable than before. This means that it is less likely to crash or produce unexpected results.

  • Overall, these changes make the decoder more reliable and easier to use.

    V59 Software can be downloaded from my page https://usradioguy.com/meteor-m2-3/ , or on happysats page

    Update instructions are on my page as well.
Screenshot of an older version of M2 LRPT Decoder
 
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RFNM Now Available for Pre-Order

Back in April we posted about the RFNM, an upcoming software defined radio project which will have eight 12-bit ADCs, up to 612 MHz real time bandwidth, and two DACs for transmitting with up to 153 MHz bandwidth. The standard board will support tuning from 600 - 7200 MHz, with tuning expanded down to 10 MHz available via an RFFC2071A mixer daughterboard. The board also has an onboard VSPA DSP processor, as well as built in ARM CPU cores, and a 16 GFLOPS GPU all of which can help process the massive bandwidth, as that full live bandwidth will be very difficult to transfer and use on a PC.

The RFNM was been released for pre-order a few weeks ago to customers who had registered interest, and has now recently been released for general pre-orders. The pricing is:

  • RFNM Motherboard - US$299: LA9310, Si5510, i.MX8MP, 4GB LPDDR4, 64GB eMMC 5.1, Machined enclosure
  • Lime Daughterboard - US$179: 1x TX/RX, 1-3500 MHz, LMS7002M 
  • Granita Daughterboard - US$249: 2x RX or 1x RX + 1x TX, 10-7200 MHz, Arctic Semi Granita, Machined enclosure 
  • Breakout Board: US$19

You will need the motherboard and at least one daughterboard.

We have been in contact with Davide Cameron, the developer behind the project and he has mentioned that a pre-production unit should be on the way to us soon for testing and review. He has noted that the software and drivers are still in development, but he has already been able to get 122 MHz out through USB to SDR++ on a machine with a fast CPU. He has also had Cyberether running well on a Mac M1, and GNU Radio on all platforms.

The RFNM Motherboard
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Creating a Multicarrier Base Station Transceiver For DMR, YSF, M17 and more with MMDVM and LimeSDR

Thank you to Adrian, creator of the QRadioLink software for writing in and sharing with us his post about how he uses a LimeSDR as an Multi Mode Digital Voice Modem (MMDVM) for various modes including DMR, YSF and M17. 

A MMDVM is usually a computing device running multiple radios, each of which is used for a separate channel with it's own filters and power amplifier hardware. Each channel can run a separate protocol if desired. 

However in order to save on radio hardware, Adrian wanted to use his LimeSDR as the radio hardware in his MMDVM system. The LimeSDR is a transceiver which has enough bandwidth to implement several channels just by itself. To do this Adrian uses his MMDVM-SDR software.

His implementation runs multiple instances of MMDVM-SDR, one instance for each channel. Then a GNU Radio flowgraph with LimeSDR block connects to each of these instances, transferring data between GNU Radio and MMDVM-SDR via ZeroMQ or TCP sockets. The bulk of Adrian's post explains the architecture in detail. Adrian writes:

The setup can transmit 7 digital carriers in 200 kHz occupied spectrum, and each radio channel can be assigned to a different mode or digital voice network as configured in MMDVMHost.

This is based on the work of Jonathan Naylor G4KLX and Rakesh Peter (r4d10n).

Adrian also notes that this is still a work in progress and there are still several limitations including high latency and issues with filtering, overload and poor channel rejection. 

Multi-Channel MMVDM LimeSDR Architecture Overview
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Recent Talks from the Society of Amateur Radio Astronomers 2023 Conference

Over on their YouTube channel there have been numerous talks uploaded over the past few months from the 2023 Society of Amateur Radio Astronomers (SARA) conference. Some of these talks are quite useful for beginner radio astronomers who are getting started with small dishes and software defined radios like the RTL-SDR.

One talk by Alex Pettit describes how to build a radio telescope from a an umbrella and some "Faraday fabric" which is copper cloth. The results show more than adequate performance for the cost, making this an affordable and easy entry to radio astronomy.

Alex Pettit - Umbrella Antennas

Another video presented by Dr. Wolfgang describes building small to medium sized radio telescopes. He explains how small radio telescopes less than 3 meters in size can work well for receiving the 21cm Hydrogen line, and how SDRs are the best choice of receiver for them. Many examples of small dish installations are shown.

Dr. Wolfgang Herrmann: Building Small/Medium Size Radio Telescopes

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Imaging TV Satellites with a DIY Radio Telescope

Over on the saveitforparts YouTube channel the creator has uploaded a video showing how he was able to image geosynchronous satellites with his modified motorized RV satellite dish. The idea is to scan the sky using the motorized dish, taking Ku-band RF power readings at each point in the sky. The result forms a heatmap image of satellite transmissions in the sky. For the most part, the satellites detected are TV satellites and they are at known positions in the sky.

However, in one of his recent scans saveitforparts appears to have detected an unknown satellite just outside of the geostationary plane. He goes on to discuss what it could have been, noting that it is most likely to be the AMSC 1 telecommunications satellite.

Recently I spotted a strange "UFO" with my homemade radio telescope / microwave imager. I've used this imager before to spot television satellites in geostationary orbit, but this unknown object was something new to me.

Spoiler Alert: I was able to determine that I'm probably seeing a geosynchronous (but not geostationary) satellite in an inclined / elliptical orbit. Specifically, I think this is the AMSC-1 telecom satellite, which is in a type of orbit designed to cover high latitudes like Northern Canada.

These types of satellites don't seem to show up too often on my telescope / imager setup, since they're not as common and aren't usually aimed directly at my location. This is the first time I've managed to spot one (if that's what I'm seeing), so it seems kind of rare to catch it with this particular equipment!

Folks might also ask if this "UFO" could be the sun or moon producing microwave signals, but those were both off to the left of the scan, not where the mystery signal showed up. It's also probably not a reflection / side lobe / "lens flare", I do get those, but they show up as rings around the main signals, and in fact this mystery signal has its own faint ring around it. Since my dish takes 3-4hrs to do a full scan, this also isn't something fast like a plane or low-orbit satellite as those don't show up on my imager (I'm essentially taking a very long time exposure).

I'm still planning to upgrade / rebuild this mini radiotelescope device in the future, hopefully with more flexibility to pick up different frequencies. That should let me see even more satellites (and maybe other space stuff!).

Mysterious Space Object Detected With DIY Radio Telescope

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A Tape Measure Antenna for Receiving HF Numbers Stations

In his Hackaday.io post (and a post on the main Hackaday blog), Tom Farnell explains how he used two 10-meter tape measures combined with an RTL-SDR Blog V3 software defined radio to receive numbers stations in the HF bands. We want to add that this antenna isn't restricted to just numbers stations, and could receive many different types of shortwave and amateur stations on HF.

In his post Tom explains what numbers stations are and why they are interesting. In brief, a numbers station is a radio broadcast of a voice saying a bunch of numbers continuously. These stations are known to be espionage related, containing some sort of coded message for international spies to decode.

Tom goes on to show how the antenna is constructed. As HF antennas need to be long to get the best reception, Tom uses the long metal tape measure and attached it to the included dipole assembly that comes with the RTL-SDR to increase them to an appropriate length. 

Intercepting Spy Radio Messages With A Tape Measure

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TechMinds: Testing the RTL-SDR Blog V4

Over on his TechMinds YouTube channel Matt has uploaded a new video showing him testing out the new RTL-SDR Blog V4 dongle that we released a couple of weeks ago. In the video Matt explains the differences between the RTL-SDR Blog V3 and V4 dongles, and then goes on to show the Blog V4 dongle in action. He finishes by comparing reception between the V3 and V4, noting the reduced interference on the HF bands due to the lack of Nyquist folding from direct sampling.

We note that the first batch of the RTL-SDR Blog has currently sold out, but a new larger batch will be ready to go on sale around the end of September. So please keep an eye on the blog's main page and store if you are interested in picking one up.

RTL SDR V4 - Now with Built-In HF Upconverter + More Features

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