UnoSDR is a simple, modern, intuitive interface, small and fast PC-based DSP application for Software Defined Radio (SDR). It’s written in C++ and Qt Quick cross-platform framework. Typical applications are Shortwave listening, Ham Radio, Radio Astronomy and Spectrum analysis.
UnoSDR supports both the RTL-SDR and soundcard based SDRs. With the RTL-SDR UnoSDR must be run via an rtl_tcp server. The software is for the Windows platform, but it seems that there is also an Android version, although this may not yet support the RTL-SDR as we could not get it to connect to our rtl_tcp server.
We tested the Windows version and it ran well despite a few glitches with trying to get the software to connect. There is also a bit of a delay when tuning due to the use of rtl_tcp, and the delays that using a network stream entail even when connected to the localhost. Also we only saw support for AM, USB, LSB and WFM modes. The other modes may be added later as the software still appears to be in development.
The Tekmanoid EGC STD-C decoder was recently updated and a new commercial paid version was released. The paid version now supports the decoding of LES STD-C messages. Previously the only other decoder that we knew of which was able to decode LES messages was the www.inmarsatdecoder.com software. The inmarsatdecoder.com software costs €100, and while the price for the Tekamanoid decoder is not advertised, it is less than €100, and a bit more affordable for the average person.
Tekmanoid STD-C Decoder Receiving LES Message.
The free versions of both decoders only decode the EGC broadcast messages which contain SafetyNET messages. These include messages like weather reports, shipping lane activity and hazards such as submarine cables and oil rig movements, pirate activity, refugee ship reports, missing ship reports, and military exercise warnings.
The paid version can decode the other non-broadcast private LES STD-C channels. LES STD-C channels typically contain email like messages sent to and from ships. Mostly it’s company messages about the ship route plans, cargo discussions, repair/fault discussions, ship performance information and weather reports etc. Sometimes small files are also downloaded. Each Inmarsat satellite contains about 7 LES channels each run by a different telecommunications company, so one may be of interest to you.
The paid version of the Tekmanoid decoder also has a nice feature for visualizing the SafetyNET EGC messages. Every now and then an alert containing coordinates and an area is sent out. Usually it is something like a distress alert from an EPIRB or the search area for a missing vessel. The decoder generates an HTML file that displays these areas on a map, alongside the text message.
STD-C EGC Distress Alert on map
The author of the Tekamnoid software allowed us to test his new paid version for free. We ran the software using signal from an Outernet patch antenna and LNA. An RTL-SDR V3 + SDR# was used as the receiver, and the audio was piped to the Tekmanoid decoder with VB-Cable. Decoding was almost flawless on both LES and EGC STD-C channels. In a previous recent update the Tekmanoid decoder was updated for improved decoding performance, and now in our opinion it is almost or just as good as the inmarsatdecoder.com software.
If you are interested in learning more about decoding Inmarsat STD-C we have a tutorial available here. LES channels for the Inmarsat satellite in operation over your geographic location can be found on UHF-Satcom’s website.
LES STD-C Inmarsat Channels
Remember that LES STD-C messages are not publicly broadcast, so in some countries it may not be legal to receive them. Most countries will have a law that says you can receive and decode the data, but you may not act upon or use to your advantage any information from the messages.
The new software requires a different DVB-T driver app to be installed first, which is also provided by Martin. This is because the RTL-SDR needs to be operated in a mode different to the way that the SDR drivers use it in. Martin has also open sourced his Android DVB-T driver and it is available on GitHub.
Aerial TV is currently free on the Google Play store, but looks like it may eventually have some in-app purchases. Also, it is currently marked as ‘Unreleased’ on Google Play, which is essentially a beta version, so you might expect there to be some bugs.
Aerial TV Screenshot
Over on YouTube user GiamMa-based researchers SDR R&D IoT has uploaded a video showing Aerial TV scanning for TV channels, and then eventually playing some video.
APP DVB Receiver Aerial TV (Unreleased) rtl sdr compatible test with oneplus one
Over on YouTube use radiosification has uploaded a video showing the Windows TETRA decoder ‘wintelive’ in action. Wintelive is a Windows port of the popular RTL-SDR compatible Linux based ‘telive’ TETRA decoder. Back in October 2016 we posted about its release and we have a tutorial for telive and the RTL-SDR available here.
Recently a reader of RTL-SDR.com wrote in and submitted a link to T——–o SDR, which is an RTL-SDR compatible multimode SDR decoder program for Windows. (The website is in Italian but is easily translated with Google Translate). In terms of operation it appears to be quite similar to SDR#, and other programs like SDR-Console and HDSDR.
Like all other general purpose receiver software it is capable of decoding NFM/AM/WFM/SSB/CW modes. It also has digital noise reduction built in as well as an S-Meter and frequency manager list.
Update: Unfortunately we have been informed by the developer of SDR# that this software was illegally decompiled from a relatively new SDR# version and is thus stolen work. We looked further into the software and it is essentially an exact clone of SDR#, just with a different skin. Please do not use this software, and respect software legality.
Essentially it appears that they took the closed source SDR# program, decompiled it then reskinned it and then made it open source under a new name.
Obviously this is unacceptable behavior, so out of respect for the original SDR# developers hard work we’ve removed links and references to this software on our website.
The R820T2 is the tuner chip used on most RTL-SDR dongles. It is also used on the Airspy, a more advanced higher end SDR. All in all, it is a very good tuner chip, but it is mostly limited by the low-bit ADC on the RTL2832U chip in the RTL-SDR.
We’ve just been informed that there is now a custom DIY breakout board available for the R820T chip which is made by Eric Brombaugh who is an SDR experimenter. This is great for those wishing to do home brew SDR experiments with the R820T2 chip, for example you could perhaps implement your own SDR with a higher end ADC chip on a development boards.
The breakout board is essentially the exact implementation which is shown in the R820T datasheet. It is available as a 4-layer PCB on Osh Park and it “provides a simple 4-pin interface with power, ground and I2C bus for controlling the tuner. A broad-band RF input and 10MHz IF output are provided on SMA connectors.” Eric has also provided us with a simplified driver based on the Airspy and Linux media driver code which allows you to control the R820T2 from an STM32F0xx processor.
Recently RTL-SDR.com reader Mark wrote in and wanted to share his modified version of otti-soft’s GNU Radio flowgraph for decoding Meteor-M2 weather satellite images on Linux. The modified version allows for real time decoding, whereas the original version requires several offline decoding steps to be performed after recording the signal.
Mark writes:
I have modified one of otti-soft’s gnuradio flowgraphs so that they work with RTL-SDR and output the demodulated symbols to a TCP socket, from which the new version of LRPT Analizer (from robonuka.ru) can decode the data in real-time.
(AFAIK, only the AMIGOS version is able to decode the data from a socket, which is required for real-time decoding).
The program is to be run under a 32-bit version of Wine.
When the satellite is overhead, open and run the flowgraph (attached) in gnuradio-companion and leave it running. You might need to adjust the gain.
Then, run the LRPToffLineDecoder.exe executable from the extracted archive. It should display a constantly-updating constellation diagram. When the data is decoded, the channel images will start to appear in each section of the window.
That’s it, when the image is decoded, one can save it and close the windows of gnuradio-companion and the decoder.
Notes: when running the flowgraph, no other processes (rtl_sdr, rtl_power, gqrx, …) should use the SDR device.
Enrique is working on a project which would record FM audio as MP3 files. To do this he uses rtl_fm with several RTL-SDR dongles. However, a major roadblock was that he found that adding five or more dongles to his server resulted in all dongles with a USB index over 3 producing the error “Failed to submit transfer 4!”.
After trying to work around the problem with Docker and VMs and ultimately failing he decided to look into other solutions. He found that rtl_test had an option to force synced output, and with this option enabled he was able to use more than four dongles. So he ended up implementing that synchronization code into rtl_fm.
With that code implemented he is now able to run up to 15 dongles on a single server. A higher amount might still be possible, but Enrique did not have that many dongles to test.
Update: On Keenerds branch he’s rejected a merge of this patch citing the following:
Synchronous mode doesn’t work. Rtl_fm used to use synchronous mode. It produced constant minor glitches that made data decoding impossible. Don’t use it.
The whole “many simultaneous dongles” problem is a well-known issue related to LibUSB. All you need to do is reduce the DEFAULT_BUF_NUMBER in librtlsdr.c and recompile.
