Category: Applications

SignalsEverywhere: Playing Classic Games over Amateur Radio with NPR-70 TCP/IP Modems

Over on her YouTube channel SignalsEverywhere, Sarah has uploaded a new video that shows us how TCP/IP connections can be made over the amateur radio spectrum using low cost NPR-70 TCP/IP modems that operate in the 70cm amateur band at around 433 MHz.

With a TCP/IP connection available it is then possible to play games over the amateur radio bands and Sarah demonstrates this in action with some classic games like Unreal Tournament 2004, noting that the ping was about 225ms. She notes that she used a lower symbol rate to keep within the legal limits within the USA, however in other regions a higher symbol rate may be possible, resulting in better ping. She goes on to try a strategy game called OpenRA which is a bit more suited to running on low speed high latency networks, noting that the radio TCP/IP connection worked very well.

In the video Sarah also shows what the modem signal looks like on the spectrum and waterfall using SDR++.

Playing Classic Games over Amateur Radio | NPR-70 Modem TCP/IP Unreal Tournament and OpenRA

Pulsar B0329+54 Detected with a 1.9m Dish and RTL-SDR

Over the past few years Job Geheniau has been constantly surprising us with his amateur radio astronomy results coming from modest dish sizes and low cost SDR equipment like an RTL-SDR. We've seen him perform full sky hydrogen line surveys, measure galactic rotation, image the Cygnus star forming region, image the Cassiopeia A supernova remnant, detect interstellar high velocity clouds and observe a red supergiant star.

Job's latest work has seen him detect Pulsar B0329+54 with his 1.9m dish and an RTL-SDR. He writes:

A pulsar is the rapidly spinning and pulsating remnant of an exploded star.

PSR B0329+54 is a pulsar approximately 3,460 light-years away in the constellation of Camelopardalis. It completes one rotation every 0.71452 seconds and is approximately 5 million years old

Everything indicates that I may have been able to detect the pulsar B0329+54 with JRT [Job's Radio Telescope]. This dish has a diameter of 1.9 meters, which would make it the first time (!) this pulsar has been detected with a dish of this size as far as I can tell. This result was obtained thanks to the good help and software of Michiel Klaassen.

Job has also provided a PDF file that documents his setup and results in more detail, which we have uploaded to our server here.

Using an SDR# Plugin to Tune into a Broadcast FM SCA Subcarrier (Radio Reading Service for the Blind)

Thank you to Double A again for submitting a new video where he shows how to use a new SDR# plugin called "SCATuner" to listen to an SCA audio subcarrier embedded within a broadcast FM signal.

SCA short for Subsidiary communications authority, is a separate audio channel hidden within a broadcast FM signal. SCA is typically used for niche radio programs, elevator music, music for doctors offices, and niche services such as reading for the visually impaired. In the past you needed a special hardware SCA radio to receive these channels, however receiving these channels with an SDR is relatively simple. Not all broadcast FM stations will have an SCA service, but the video shown below explains how to find one.

In previous posts Double A and others have shown how to receive these SCA Subcarriers using two instances of SDR#. However, this new plugin makes the task much simpler one click job.

Double A's video goes over how to install and use the plugin, explains SCA and demonstrates it in action decoding a radio reading service for the blind.

SDR# Plugin for Tuning an FM SCA Subcarrier (Radio Reading Service for the Blind) (with RTL-SDR USB)

Using an RTL-SDR to Decode Broadcast FM RDS Data on Android

Over on YouTube Double A Labs has posted a new video demonstrating how to use an RTL-SDR and Android device to receive broadcast FM stations, and to decode any associated RDS data. 

In the video Double A uses the SDR Touch Android app and the Advanced RDS function to show the RDS information. He goes on to explain the various pieces of information RDS data provides including clock time, active RDS groups and alternative frequencies.

Tune broadcast FM radio and decode Radio Data System (RDS) information using your Android phone and an RTL-SDR USB (see parts list below). RDS can include station identification, song name, the current time for a receiver to sync its clock, alternative frequencies the same program is on, and more!

Tuning FM Radio & Decoding RDS Data on ANDROID using RTL-SDR USB

RTL-SDR Virtual Reality Spectrum Display Software Released

Back in September 2021 we posted about Manahiyo's software that allows the RF spectrum and related graphs to be viewed in virtual reality, using a VR headset and an RTL-SDR. Back then the software was only demonstrated on YouTube, but not released.

A few days ago Manahiyo released the VR software on GitHub. The software requires a Oculus/Meta Quest2 VR headset, and the it is able to run directly on the headset's computing hardware. This makes it possible to have the RTL-SDR attached to the headset itself.

RTL-SDR VR Software for Oculus Quest 2

Frugal Radio: Travelling with SDR & Scanner Gear

Over on his YouTube channel Frugal Radio, Rob has uploaded a new video whilst on holiday travelling through the USA. In the video he shows what sort of scanner radios, antennas and SDR gear he carries with him on his travels. His gear includes a Uniden SDS-100 scanner, a BCD325 scanner, a Radio-Tone RT4 internet network radio and of course an RTL-SDR Blog V3 and laptop.

He goes on to demonstrate the hardware in action from his Hotel room, decoding local digital audio.

A peek in Frugal's Travel Bag : SDR & Scanner gear on the road

Lon.TV Demonstrates Decoding Various Digital Signals with RTL-SDR

Tech YouTuber Lon.TV has recently uploaded a video demonstrating how to identify and decode various digital transmissions with an RTL-SDR dongle. In the video he explains how to use VB Cable to pipe audio from SDR# into various decoders, and then goes on to show DMR, APRS, POCSAG, L-Band AERO, FT8, and JS8/JS8CALL all being decoded via an RTL-SDR Blog V3 dongle.

Software Defined Radio Part 2 - Decoding Digital Transmissions with an RTL-SDR USB Radio

SDRSharp Guide V4.2 Released

Paolo Romani (IZ1MLL) has recently released version 4.2 of his SDRSharp PDF Guide. The book is available for download on the Airspy downloads page, just scroll down to the title "SDR# Big Book in English".

As before the document is a detailed guide about how to use SDRSharp, which is the software provided by Airspy. While intended for Airspy devices, SDRSharp also supports a number of third party SDRs, including the RTL-SDR, and it is the software we recommend starting with when using an RTL-SDR.

Paolo writes:

My new v4.2 SDRsharp PDF is out. The guide is now 139 pages long, and covers all the settings, UI customization, included and third party plugins, and use of some external decoders and software, now with Spyserver integration with Raspberry Pi 3/4, etc etc...