SignalsEverywhere: SDRTrunk P25 Police Scanner Tutorial with two RTL-SDRs

Over on YouTube Sarah from SignalsEverywhere has uploaded a new tutorial video showing how to use two RTL-SDR dongles with the free SDRTrunk software to create a P25 Police scanner.

In the video she first shows how to install SDRTrunk in Windows and Linux, then how to install the JMBE codec required for decoding audio. She goes on to show how to import trunked system network data from a (paid) RadioReference subscription, how to blacklist unwanted talkgroups, and how to optimize operation with two RTL-SDR tuners. Finally she also shows how to set up the system manually if you don't have a RadioReference subscription.

SDRTrunk The FREE P25 Police Scanner! Windows and Linux Tutorial

Australian Teenager Exposes COVID-19 Patient Data via POCSAG Pager Network

A 15 year old Australian teenager has been accused of leaking sensitive COVID-19 patient data such as the phone numbers and addresses of people in quarantine, and conversations between health officials and doctors about COVID-19 patients. The leak occurred via a public web page that he had set up to share decoded POCSAG pager data that he received from his home.

Pagers are still typically used in many parts of the world by hospitals. It is a tried, tested and very reliable system for messaging, however most systems in the world send data out in unencrypted plain text for all to see. Anyone with a cheap scanner radio or $20 SDR and freely available software can decode every single message sent via paging from almost anywhere in a city as the signals are often extremely strong. Pagers are intended to be reserved for urgent infallible messaging, as paging is more reliable compared to mobile SMS since SMS messages do not always get through, or can be delayed by several minutes. Alternative secure communication channels such as SMS should be used for private information, however this protocol is not always followed due to the additional hassle.

The teen appears to have used either a Baofeng or RTL-SDR to receive the POCSAG pager signal available in his hometown in Western Australia. The pager signal was decoded with multimon-ng, and displayed via the PagerMon software. PagerMon creates a web page that displays pager messages in an easily readable format, and the page can be made accessible to the internet if desired. It seems that the teen is a scanner enthusiast, and did not intend to purposely leak patient data, however others found his PagerMon page and brought it to the attention of the media. His site has now been shut down, and officials have decided to shut down the pager system in favour of a double SMS system.

Some of the leaked messages via 9 News Perth
Some of the leaked pager messages via 9 News Perth

This is a story that repeats often all around the world. In the past we've seen whistleblowers report on patient data breaches in VancouverKansas, and via an art installation in New York that continuously printed out pager messages.

Alpha Version of SDR++ Released

SDR++ is an open source general purpose cross platform SDR program that Alexandre Rouma (@WhatsTheGeekYT) has been working on for the past few months. Recently he released his first Windows Alpha version to the public which is available from the GitHub release page. The SDR++ GUI is inspired by SDR#, however, SDR++ as you might guess is programmed in C++ instead of C#.

In order to use SDR++ on Windows you will first need to have installed PothosSDR for the SoapySDR and volk support. To do this you can follow the instructions here. Thanks to the SoapySDR support it is able to run with most SDRs including the RTL-SDR.

To start the program, select your SDR from the source menu, change the sample rate (which is set to the minimum value by default), then click the play button. We tested it with both an RTL-SDR and HackRF, and both units worked just fine, although at lower sample rates the waterfall was a bit choppy. We do note that the software is very much in the alpha phase with only a few features implemented, and most menu items do not work yet. But the main features including WFM, FM, AM, SSB, CW demodulation as well as the spectrum and waterfall are all functional. Unfortunately there do seem to be a few stability issues as we experienced frequent crashes on our PC.

We'll be watching this software with interest to see how it progresses.

Current Features

  • Uses SoapySDR for wide hardware support
  • Hardware accelerated graphics (OpenGL + ImGui)
  • SIMD accelerated DSP (parts of the DSP are still missing)
  • Cross-platform
  • Full waterfall update when possible. Makes browsing signals easier and more pleasant

Coming soon

  • Multi-VFO
  • Plugins
  • Digital demodulators and decoders
  • Quick replay (replay last n seconds, cool if you missed a short signal)

Small things to add

  • Switchable bandwidth for demodulators
  • Switchable audio output device and sample rate
  • Recording
  • Light theme (I know you weirdos exist lol)
  • Waterfall color scheme editor
  • Switchable fft size
  • Bias-T enable/disable
  • other small customisation options
  • Save waterfall and demod settings between sessions
  • "Hide sidebar" option
  • Input filter bandwidth option

Known issues (please check before reporting)

  • Random crashes (yikes)
  • Gains aren't stepped
  • The default gains might contain a bogus value before being adjusted
  • Clicks in the audio
  • In some cases, it takes a long time to select a device (RTL-SDR in particular)
  • Min and Max buttons can get unachievable values (eg. min > max or min = max);
The SDR++ Interface
The SDR++ Interface

Frugal Radio: Using an Airspy and RTL-SDR To Scan the UHF Military Airband in SDR#

In Frugal Radio's latest video he explores how you can use an Airspy or RTL-SDR dongle to scan the entire military UHF airband spectrum in a few seconds via SDR#. Frugal Radio notes that there are often many signals in the UHF milair band, but they can be difficult to find without a scanner.

In the first video he compares his Uniden BCT15X hardware radio scanner against an Airpsy, noting that his Uniden takes 1:10 minutes to scan the entire band, whereas the Airspy running SDR# with the frequency scanner community plugin can scan the same bandwidth in less than 2.5 seconds. Faster scanning means that you are less likely to miss an active signal. In the second video he tries scanning with an RTL-SDR and notes that it can scan the band in 9 seconds.

How to use Frequency Scanner to Search UHF MilAir in 2.3 seconds in SDR# using AirSpy R2

$25 RTL-SDR v3 Military Air band search in under 10 seconds! Frequency Scanner SDR Sharp plugin test

The NEWSDR 2020 Conference will be held Online on 12 August

The 10th New England Workshop on Software Defined Radio (NEWSDR 2020) will be held online this year due to the ongoing pandemic. It is due to be held on 12 August 2020, 9:00 AM (US Eastern) – 5:00 PM (US Eastern). Registration is free, however you do need to register before 9 August 2020 in order to receive login details.

The 2020 New England Workshop on Software-Defined Radio (NEWSDR’20) is the tenth installment of an annual workshop series organized by the Boston SDR User Group (SDR-Boston). Given the continued global health emergency of the COVID-19 pandemic, this year’s event will be safely hosted online using a variety of Internet technologies such as Zoom, YouTube Live, and Slack. Although this will be a virtual event, the NEWSDR 2020 organizers are committed to achieving the primary goal of this workshop by providing a forum that enables individuals working on SDR-related projects within the New England area to get together, collaborate, and introduce SDR concepts to those interested in furthering their knowledge of SDR capabilities and available resources. NEWSDR 2020 welcomes both experienced SDR enthusiasts as well as individuals who are interested in getting started with SDR.

This years talks include a Keynote by Dr. Tom Rondeau of DARPA, “Spectral Coexistence: What is its future in the US?”, “A Software-Defined Wireless Communications Network Research Infrastructure for the Internet of Things (IoT)”, “Open-Source Software in Software-Defined Radio” as well as several community and poster talks.

Videos of previous NEWSDR conference talks can be found listed on their website.

NEWSDR 2020 to be held online
NEWSDR 2020 to be held online

RadioSlate: A Tablet with Built in LimeSDR or HackRF

A new project called "RadioSlate" has recently been announced by Yian IT, a Chinese IoT company. RadioSlate will be an SDR-enabled tablet designed to be used with a HackRF or LimeSDR software defined radio that will be mounted internally behind the screen under some metal shielding. The tablet uses a 1024 x 600 touchscreen and runs an Intel M3 8100Y 1.1 to 3.4 GHz dual core CPU with 8GB of RAM, 64GB of storage and it supports both Linux and Windows. Batteries will not be included, but it supports batteries in the standard 18650 form factor which can be purchased anywhere.

The project is due to be crowdfunded on CrowdSupply in the near future, and you can currently sign up to receive updates and be notified when the project launches. They write:

RadioSlate is a sturdy aluminum tablet with an industry-favorite software-defined radio (SDR) board—your choice of HackRF or LimeSDR—tucked away behind its touchscreen. Whether you’re a Ham radio operator, a network engineer, a mobile base station designer, a security auditor, or some other variety of SDR enthusiast, RadioSlate lets you do your thing, even if that thing requires you to go outside and walk around, get unusually close to transmitters and receivers, keep one hand free for other tasks, or manage all of the above without drawing undue attention to yourself.

Explore the spectrum, while on the go, without having to drag along your laptop, an SDR board, and cables.

The RadioSlate: An SDR-enabled Tablet
The RadioSlate: An SDR-enabled Tablet

Using CubicSDR, rtl_433, MQTT and Telegraf to Stream Live Data to InfluxDB

Nimrod makes his own sourdough and wanted a way to track the temperature and humidity of the bread making environment. To do this he's set up a system involving rtl_433 on a Raspberry Pi which live streams all of his home temperature/humidity sensor data into InfluxDB. The program rtl_433 is software for the RTL-SDR that allows users to receive data from many different brands of home weather/temperature sensors, as well as many other wireless ISM band devices. InfluxDB is a type of database that specializes in storing and displaying time series data from sources like sensors.

The chain of data starts with rtl_433 which collects the temperature sensor data via an RTL-SDR. The output of rtl_433 is sent to Mosquitto, an MQTT messaging protocol server. A program called Telegraf then subscribes to the MQTT queue, and parses and transmits the metrics to InfluxDB. InfluxDB finally records the data, and provides graphical plots. 

Nimrod's post is a full tutorial showing how to download and set up each of the programs used in the system, and how to view the data collected with InfluxDBs graphing system.

RTL_433 temperature graphs via InfluxDB
RTL_433 temperature graphs via InfluxDB

SignalsEverywhere: Decoding Digital Data via Audacity, Mulitmon-ng and MiniModem

SignalsEverywhere is back this week and in her latest video Sarah talks about using a combination of Audacity, Minimodem and Multimon-ng to decode digital data that could be obtained from an SDR or other signal source.

Sarah was interested in the 2020 Hackasat space security challenge and specifically in completing the 56k Flex Magic challenge which consists of an emulated signal from an old 56k modem. Within the 56k modem signal is secret information required to complete the challenge.

Sarah first shows how to use Multimon-ng to decode the DTMF tone section of the signal. These are the tones heard when dialling on a landline phone. She then goes on to show how to use Audacity in spectrogram mode to take a closer look and analyze the next chunk of the signal. Then by using the information gained about the signal from the spectrogram analysis she is able to decode the data via minimodem.

Audacity Decoding Data?! Using Audacity Multimon-ng and Minimodem to Decode Digital Audio Data!