Rob from Frugal Radio has recently started a new YouTube series all about monitoring aviation communications. In his first video Rob gives an overview on what can be aviation signals can monitored and recommends a few hardware scanners as well as software defined radios for monitoring.
This is an introductory video to my new series aimed about monitoring aviation communications. Throughout the series we will talk about:
Civil Airband (aka VHF airband)
Military Airband (aka UHF airband)
HF Aeronautical communications
Decoding aircraft data on HF and VHF
Decoding CPDLC transmissions and much more!
Good frequency scanners to use, like the Uniden BC125AT and BCT-15X
Thank you to Paolo Romani IZ1MLL for letting us know that he has updated his popular SDRSharp users guide that we posted about previously last December. The guide is available on the Airspy downloads page. SDR# (aka SDRSharp) from Airpsy.com is designed for Airspy SDRs, however it is one of the most popular SDR receiver programs that is used with RTL-SDRs as well. Paolo's guide covers all of the settings and features in SDR# as well as some third party plugins. Paolo writes:
In the last month I have completely rewritten the guide for other devices and for the latest radical changes to the software. From today, version 2.1 is available in Italian and English for all interested guys.
We note that the guide has also been translated in Spanish and Russian, although at the time of writing those translations are still only for the older guide.
Aside from these results, Steve's post goes on to explain how he gathers and stores these analytics and an example of using the Graphs1090 software for producing nice plots of the aircraft receive. One important tip that he mentions is to be careful when constantly logging ADS-B data to the SD card as the card can easily get corrupted over time since there are read/write cycle limits.
Air traffic graphs showing the effect of the latest snow storm on air traffic
Recently we posted about how SDR# was updated to the latest .NET 5 framework, and this brought with it a new plugin SDK for developers. If you're wanting to get started with plugin development, Petri-Veikko Alajärvi (OH1GIU) has uploaded a tutorial showing how to get started with the free Visual Studio 2019 Community IDE. His post shows how to create a new project, how to add references to the SDRSharp plugin files and how to set up and test a basic GUI via an RDS information display example.
Creating a new SDR# Plugin with the .NET5 Plugin SDK
In the past we've posted several times about how 1.42 GHz Hydrogen Line amateur radio telescopes used with RTL-SDRs or other SDRs for Hydrogen line observations of the galaxy. Recently Hackaday ran a post highlighting a project from "PhysicsOpenLab" describing an 11.2 GHz radio telescope that uses an Airspy SDR as the receiver.
Celestial bodies emit radio waves all across the radio spectrum and typically observations can be made anywhere between 20 MHz to 20 GHz. Choosing an optimal frequency it is a tradeoff between antenna size, directivity and avoiding man made noise. For these reasons, observations at 10-12 GHz are most suitable for amateur radio telescopes.
The posts by PhysicsOpenLab are split into two. The first post highlights the hardware used which includes a 1.2m prime focus dish, and 11.2 GHz TV LNB, a wideband amplifier, a SAW filter, a bias tee, and the Airspy SDR. The LNB converts the 11.2 GHz signal down to 1.4 GHz which can be received by the Airspy. Once at 1.4 GHz it's possible then to use existing commercial filters and amplifiers designed for Hydrogen line observations.
The second post explains the GNU Radio based software implementation and the mathematical equations required to understand the gathered data. Finally in this post they also graph some results gathered during a solar and lunar transit.
Finally they note that even a 1.2m dish is quite small for a radio telescopic, but it may be possible to detect the emissions from the Milky Way and other celestial radio sources such as nebulae like Cassiopeia A, Taurus A and Cygnus A a radio galaxy.
A 11.2 GHz 1.2m Amateur Radio Telescope with GNU Radio and Airspy
Back in July 2020 we first posted about the alpha release of "SDR++" which back then was a new project by "Whatsthegeek" that was determined to bring an open source, cross platform, C++ based GUI general receiver program for various SDRs including the RTL-SDR to the community. Over the past few months the author has been working hard on updating the software, and it's looking a lot more mature today. Recently he has released the following updates as mentioned on his Reddit post:
As some of you might remember, I posted back in june about my SDR++ project. During the past 6 months, I've been hard at work to make it into usable software! The versions I released in june and july were extremely buggy and unusable. All of those issues have now been fixed. It's now simple to build and install. Here's a small rundown of the features it now has:
Fully modular architecture (plugins)
Multi-VFO
Support for most SDRs through dedicated modules or SoapySDR
Both baseband and audio recording with a level meter and volume adjust
Multiple bandplans available (very easy to write your own)
Switchable waterall colormap
Low CPU usage (lower than GQRX, CubicSDR, SDRConsole and in some cases SDR#)
Full waterfall update when zooming or changing min/max level
Also, SDR++ now runs on Windows, Linux, OSX and BSD! Do note that it still has a few quirks and misses some features (see https://github.com/AlexandreRouma/SDRPlusPlus/projects/2 for the todo list) In addition to what's in the todo list, decoders for common satellites will be written very soon. They will allow decoding of Meteor and NOAA with no external software needed!
I'd like to thank Airspy, Analog Devices, SDRplay and Howard Su for sending samples of their hardware for development! Would never have been able to add support for their hardware without it!
I hope this software will be useful to the community :)
SDR++ GUI
Releases for Debian Linux and Windows can be found over on the GitHub Releases page.
We note that over on Twitter Whatsthegeek (@ryzerth) has been releasing further updates. He notes that some of the latest code updates for SDR++ add a native RTL-SDR module including bias tee support, and that it is also now available as a package for Arch Linux users over on the user Repository. However these latest updates are not yet available as binaries on the releases page.
In a recent tweet he also demonstrates the very useful looking multi-vfo feature allowing him to decode three AERO signals with Jaero simultaneously on a single RTL-SDR dongle.
SDR++ Running two Jaero instances and 3 demodulators at once from a RTL-TCP server thousands of km away. (with a waterfall running at 1440p). Quite low CPU usage!#sdr#sdrpp#rtlsdrpic.twitter.com/LuX1nRZZPA
Developer @dernasherbrezon has recently released a new program called "sdr-server" which is a streaming server. Unlike the more basic rtl_tcp server, sdr-server has some more advanced features like being able to serve multiple clients a slice of the bandwidth simultaneously. When compared to SpyServer, another advanced RTL-SDR compatible streaming server, sdr-server has similar features, however, sdr-server is open source. Some of the key features include:
Share available RF bandwidth between several independent clients:
Total bandwidth can be 2016000 samples/sec at 436,600,000 hz
One client might request 48000 samples/sec at 436,700,000 hz
Another client might request 96000 samples/sec at 435,000,000 hz
Several clients can access the same band simultaneously
Output saved onto disk or streamed back via TCP socket
Output can be gzipped (by default = true)
Output will be decimated to the requested bandwidth
Clients can request overlapping RF spectrum
Rtl-sdr starts only after first client connects (i.e. saves solar power &etc). Stops only when the last client disconnects
MacOS and Linux (Debian Raspberrypi)
How bandwidth slices can be shared with sdr-server.
The popular SDR# (SDRSharp) software has recently been updated to version 1788, and now runs on the .NET5 SDK. Most of the upgrades are behind the scenes, but generally the new version appears to be more memory efficient and loads faster. The new version also brings more theme and layout customizations and as explained further below an improved plugin SDK for developers.
In order to install the latest version you will need to download .NET5 runtime from Microsoft which may not already be on your system. For RTL-SDR users you can then run install-rtlsdr.bat then start the software as usual.
One of the most exciting new developments is the new .NET 5 plugin SDK that is now available. This allows third party developers to easily code up plugins for SDR#. While a plugin SDK already existed before, the new version appears to make development much simpler, and also comes with a few examples to help get developers started quickly. The result is that we should start to see more plugins appearing in the future with more features.
SDR# .NET5 Plugin SDK Example Code
One plugin called Scytale-C for Inmarsat STD-C channel decoding has already been updated to the new SDK. The developer notes that the plugin now works great with the SDR# "slicer" feature, which allows users to decode multiple STD-C signals within the received bandwidth at the same time.
We've also recently seen reports of Twitter users having success with running this new SDR# version on WINE under Linux. Unfortunately direct USB still doesn't work under WINE, but it would still function via SpyServer or rtl_tcp.
