Category: Applications

Video Tutorial on Decoding FT-8 and RTTY with an SDRplay RSP1A

Over on YouTube radio content creator Techminds has recently started a series that shows how to decode various signals using an SDR such as the SDRplay RSP1A. The first video explains what FT-8 is and shows how to decode it using the WSJT-X software. FT-8 is a modern digital HF ham mode that is designed to be receivable even in weak signal reception. However, the amount of information sent in a FT-8 message is small, so it is not possible to have a full conversation, and you can only make contacts.

In his second video Tech Minds explains RTTY and also shows how to decode it. RTTY is another much older mode that is used by the military as well as hams. To decode it he uses Digital Master 780 which is a program included in the Ham Radio Deluxe software.

Decoding FT-8 With WSJT-X And A SDRplay RSP1A SDR Receiver

Decoding RTTY With Digital Master And A SDRplay RSP1A SDR Receiver

Radio For Everyone: Testing the RTL-SDR.com Triple Filtered ADS-B LNA, Amplified Coketenna

Akos, author of his blog 'Radio for Everyone' has recently reviewed our new RTL-SDR.com Triple Filtered ADS-B LNA. In the review he compares our ADS-B LNA against another external ADS-B LNA by Uputronics and against the FlightAware Prostick and Prostick+. The tests use the external LNA's plugged directly into the dongle in order to more fairly compare against the FlightAware dongles which have LNA's built in to the dongles themselves. From his results the RTL-SDR.com ADS-B LNA appears to have near identical results with the Uputronics LNA, and slightly better results compared to the FlightAware dongles. Akos has not yet tested the main use-case of the LNA, which is to use it at the end of a run of coax cable, however he plans to do this in a future test. Also in his second post Akos shows how to build a simple amplified Coketenna using our ADS-B LNA.

On the subject of ADS-B performance we note that there are two ways to set up a system for optimal reception (apart from the antenna). The first is to place the computing and radio devices (such as a Raspberry Pi and RTL-SDR) as close to the antenna as possible (leaving a ~1m coax run to avoid local interference from the Pi). For this type of setup it is cheaper to use a FlightAware Prostick Plus RTL-SDR dongle since this has an ADS-B LNA built into it. However, the disadvantage is that you may need to set up a Power over Ethernet system, or find a remote power source, and possibly place the Pi in a difficult to service location such as in an attic or up a mast.

The second option is to use an external ADS-B LNA close to the antenna, and run coax down to the computing device which is positioned in a more accessible location. The LNA will negate any losses in the coax cable, and with high enough gain on the LNA, using quality coax is not such a high requirement since those losses are negated by sufficient LNA gain. Both methods will yield similar excellent performance.

Tested ADS-B LNA's and ADS-B RTL-SDR Dongles
Tested ADS-B LNA's and ADS-B RTL-SDR Dongles

Wired Article about Radiosonde (Weather Balloon) Hunting

Wired.com has recently run a short article about Roland F5ZV's hobby of radiosonde hunting. A radiosonde is a small box containing electronic sensors that measure things like wind, temperature, humidity and also give out a GPS location. The radiosonde is carried into the upper atmosphere by a weather balloon, and these probes are usually launched twice a day in many locations around the world by meteorological agencies. The data is useful for weather forecasting and research.

The wired article discusses the hobby of radiosonde hunting, which is the sport of using radios to hunt and collect the radiosonde as it bursts and falls back to earth. He also writes how he was able to convince the Swiss Meteorological agency to allow him to attach a GoPro to a radiosonde which allowed him to capture some interesting images.

We'd like to remind readers that in many places in the world it is possible to receive and decode radiosonde data with an RTL-SDR, and we have a tutorial available here.

Radiosonde in flight captured by a GoPro camera.
Radiosonde in flight captured by a GoPro camera.

Real Time Passive Radar Running Native on the ADALM-PLUTO ARM CPU

The ADALM-Pluto (aka PlutoSDR) is a US$149 TX/RX capable SDR that we have posted about several times in the past. It has a tuning range from 70 MHz to 6000 MHz with a bandwidth of up to 56 MHz (with software hack applied). One additional useful feature on the PlutoSDR is it's built in ARM CPU, which can be used to run programs on board the SDR itself. 

Over on his blog Mike has shown how he implemented simple passive radar code on the PlutoSDR's ARM processor. This means that no PC or other hardware is required to process the data, the entire script can be run via a SSH connection to the PlutoSDR. Mike doesn't seem to have shared his script anywhere, but one of his previous posts explains the process. The script creates the video in real time on board the PlutoSDR's ARM CPU, which is then streamed via ffplay to a PC with a screen. On his second post Mike shows some extra videos of passive radar working with FM Broadcast and DVB-T signals.

Passive radar is a radio technique allows you to detect and track RF reflective objects such as aircraft using strong signals from already existing transmission towers, such as broadcast FM or DVB-T signals.

Viewing Drone Signals with HackRF being used as a Wideband Spectrum Analyzer

Over on his YouTube channel user Andy Clarke has uploaded a video where he demonstrates his HackRF being used as a wideband spectrum analyzer with the HackRF Spectrum Analyzer software. About a year ago the HackRF team released a new firmware update which enabled the HackRF to be able to sweep through the frequency spectrum at a rate of up to 8 GHz per second. This allowed the HackRF to be used as a wideband spectrum analyzer which is able to display an arbitrarily large swath of spectrum. Shortly after the firmware update spectrum analyzer program by 'pavsa' was released on GitHub.

In the video Andy demonstrates the HackRF being used to view the WiFi band and show a 2.4 GHz WiFi connection between a drone and it's controller. He also shows it working with a handheld radio and the uplink of his mobile phone. Andy hopes to use the HackRF to avoid losing his drones due to interference.

Software Defined Spectrum Analyser - Hack RF

SDR# TETRA Plugin Updated: No longer requires MSYS2

Last week we posted about the release of a new TETRA decoder plugin for SDR#. The plugin made setting up a TETRA decoder significantly easier compared to previous methods, but it still required the installation and use of the MSYS2 environment on Windows. 

Thanks to reader Zlati for letting us know that the TETRA plugin has recently been updated once again and now no longer requires MSYS2 to be installed first. Now it is as easy to install as any other plugin, just drop the .dlls into the SDR# folder and add the magicline to the plugins.xml file. We tested it out and decoding worked fine. At the moment the "Net info" button is not working however.

x64 plugin: https://yadi.sk/d/StPod0Op3SkpKh
x86 plugin: https://yadi.sk/d/f0SS97Rb3SoyNr

New Link: http://rtl-sdr.ru/page/obnovlen-meteor-i-tetra-plagin

In the future news and download lines for newer versions will probably be available on the programmers radioscanner.ru forum thread which is available here (use Google Translate to read): http://www.radioscanner.ru/forum/topic50051-9.html

Updated TETRA Decoder Plugin
Updated TETRA Decoder Plugin

Receiving WSPR with an RTL-SDR V3 and with Automatic Band Changing

RTL-SDR V3 + Raspberry Pi WSPR Receiver
RTL-SDR V3 + Raspberry Pi WSPR Receiver

WSPR (pronounced "Whisper") is short for Weak Signal Propagation Reporting, and is a HF ham mode typically run on very low power levels such as 1W. The data from WSPR reception can be used to determine how good or bad HF propagation is currently around the world as each WSPR message contains a callsign, 6-digit locator and the transmit power level used. Received messages are all reported to the internet and can be viewed on an online map at http://wsprnet.org/drupal/wsprnet/map.

With an RTL-SDR V3 running in direct sampling mode it is possible to receive and decode these messages on a Raspberry Pi 3 using the WSPRD software.

Over on his website IT9YBG has uploaded a tutorial for a method that allows the WSPRD software to automatically change bands depending on the time of day. The method simply uses the crontab in Linux to automatically run a script that stops and then restarts WSPRD on a new frequency at certain times of the day. This is useful because different WSPR bands tend to become active at different times of the day due to changing HF propagation conditions.

WSPR messages received from all over the world.
WSPR messages received by IT9YBG from all over the world.

A Guide to Using SDR-Console V3 for Accessing and Creating Remote Servers

Jon Hudson, head of marketing at SDRplay has recently released a helpful tutorial that shows how to access remote servers in SDR-Console V3, and also how to set up your own server too. As you may already know, SDR-Console V3 provides a remote server platform which allows you to access all sorts of SDR hardware remotely over a network connection or over the internet. Some SDR hardware owners even opt to share their radio hardware publicly over the internet for anyone to access. The video description reads:

This video is a screen-by-screen guide to both accessing, and setting up your own, remote SDR radio using the new (Feb 2018) SDR Console V3 software from SDR-Radio. Although the guide uses an RSP2 from SDRplay, this will work with all the popular SDRs

Please note - you need to have a good internet connection since (unlike in V2), the entire I/Q data is being sent over the internet. This also limits how much visual bandwidth you are can see at any one time.

Links referenced in this video:
www.sdr-radio.com
http://www.sdr-radio.com/Software/Version3/Server
www.sdrplay.com
More videos on https://www.youtube.com/c/SDRplayRSP

SOME IMPORTANT WARNINGS IF YOU ARE ADDING YOUR OWN SDR!
Be careful not to plug multiple SDRs into a single USB2 socket - for multiple SDRs, you may need a powered hub ( like this: https://www.amazon.co.uk/UGREEN-Adapt... )

Once you are up and running - please go to http://www.sdr-radio.com/Software/Ver... and view your listing - if there is a yellow triangle, then you are not accessible outside your own firewall - attention is needed! Just because you can access it on your own LAN doesn't mean it's accessible via the internet!!!

The RSP family of SDRs from SDRplay cover 1kHz to 2 GHz with no gaps and give up to 10MHz spectrum visibility.

Jon's video first shows how to use SDR-Console V3 to access those publicly shared SDR radios over the internet. The second part of the video demonstrates how to set up your own server that you can use remotely for personal use, or to share over the internet.

The SDR-Console V3 server accepts various kinds of SDR hardware including RTL-SDR, Airspy, SDRplay, HackRF, Elad, LimeSDR and many more SDR units so this is a good way to explore various types of hardware, or simply to explore signals from different areas around the world.

SDR-Console remote access for SDR Radios