SignalsEverywhere: Build an RTL-SDR Based OP25 Radio Scanner with a Mobile Control Head Android App

Welcome back to Sarah from the SignalsEverywhere YouTube channel who has recently returned to producing videos from a hiatus. In her latest video, Sarah shows off her new OP25 Mobile Control Head Android App which allows you to implement a full P25 digital radio scanner at a fraction of the cost of a commercial digital scanner. In the past, Sarah had released a similar application written for the Raspberry Pi but has decided to shift her focus to writing an equivalent Android app that is less clunky and can be deployed for a lower cost. 

The app controls and displays information from the OP25 software that runs on a Raspberry Pi with RTL-SDR connected. It works by using a server application on the Raspberry Pi that manipulates the OP25 instance and its configuration files.

Sarah writes:

The application is a wrapper for OP25 that uses a raspberry pi and an android device to provide users with a mobile control head for their OP25 P25 scanner setup. Currently it's just a basic application but I'll be adding features like automatic site switching, etc.

OP25MCH: https://github.com/SarahRoseLives/OP25MCH

There is also a separate application I call the OP25Display which is just a display for a users existing OP25 instance.

OP25Display: https://github.com/SarahRoseLives/op25display

Build Your Own Digital Radio Scanner With OP25 Mobile Control Head App

A 3D Printed Enclosure with USB Hub for RTL-SDR Blog Units

Over on Hackaday, we've seen a post about Jay Doscher's clever 3D printed enclosure that can hold two RTL-SDR Blog V4 units and a USB hub. The enclosure is designed to make it easy to take the two units mobile, and the USB hub inside means that only one USB connection is required to run the two units.

Jay has also thought about cooling, allowing for space between the two dongles, and adding vent holes. He has also ensured that the SMA ports on the dongles are protected while allowing space to hand-tighten the connectors.

Jay writes that he has tested his enclosure with RTL-SDR Blog V4 units, but given that the dimensions of the V3 (and V2) are the same, it will work for those units too.

A 3D Printed RTL-SDR Blog Enclosure with USB Hub
A 3D Printed RTL-SDR Blog Enclosure with USB Hub

uSDR Software Updated to V1.7.0

Thank you to Viol for writing in and letting us know that his uSDR software has recently been updated to V1.7.0. The uSDR software (not to be confused with the unrelated uSDR hardware) is a lightweight general-purpose multimode program for Windows that supports the RTL-SDR, Airspy, BladeRF, HackRF, LimeSDR, and other SDR radios.

Viol highlights the latest features added in the 1.7.0 update below:

  • Fobos SDR frontend native support, the very new SDR from RigExpert
  • bladeRF API v2.5.0 support, oversampling mode up to 122.88 MHz sample rate (do not forget to update FX3 firmware)
  • advanced IQ playback mode, precise timing and streaming
  • improved DSP routines and memory management, minimized CPU load
  • excellent ruler tool for spectrum frequency and amplitude measurements
uSDR Updated to Version 1.7.0. Images shows FobosSDR support.
uSDR Updated to Version 1.7.0. Images shows FobosSDR support.

Airspy HF+ Ranger: A New Airspy Product Teased

Over on Twitter/X @lamdbaprog, creator of Airspy products and the SDRSharp software has teased his next upcoming software-defined radio hardware called the "Airspy HF+ Ranger". The Airspy HF+ Ranger prototype was also seen at the Dayton Hamvention through their local Airspy.us reseller.

The specifications appear to be very impressive, with a wide frequency range of 0.5 kHz to 1750 MHz and excellent sensitivity, linearity, and dynamic range figures. The Ranger is based on the same main RF chips used in the HF+ Discovery, so it will retain the relatively small maximum bandwidth capability of 710 kHz. However, for many use-cases this small bandwidth is more than sufficient.

Currently, there is no word on a release date or pricing but given the prototype status, it must be close. We expect this to be priced higher than the Airspy HF+ Discovery which sells for US$169.

Update: A page for the Airspy Ranger is now on the Airspy website. It shows a block diagram and further details. RTL-SDR.COM reader Ladislav has also sent us a PDF with the specs and a Dynamic Performance graph.

Over on Twitter/X, patrons of the Dayton Hamvention event have posted a few pictures of the display.

@lamdbaprog also demonstrates the incredible dynamic range of the Ranger when up against strong pager signals in Paris.

Scott Manley Explains GPS Jamming & Spoofing and Why & Who is Causing It

In recent years GPS spoofing and jamming have become quite commonplace. Recently popular YouTuber Scott Manley uploaded a video explaining exactly what GPS spoofing and jamming is and explains a bit about who is doing it and why.

In the video Scott explains how aircraft now routinely use GPS as a dominant navigational sensor and how some commercial flights have been suspended due to GPS jamming. Scott explains how ADS-B data can be used to determine the source of GPS jamming (via gpsjam.org) and shows hotspots stemming from Russia. He goes on to show how drone shows have also failed in China either due to GPS jamming by rival companies or due to Chinese military warship jamming. Scott then explains a bit about GPS and how jamming and spoofing work.

GPS Jamming & Spoofing - How Does It Work, And Who's Doing It?

YouTube Video Series on Iridium Satellite Decoding with an Airspy, RTL-SDR Blog Patch Antenna and DragonOS

Over on his YouTube channel, Rob VK8FOES has started a new video series about Iridium Satellite Decoding. Iridium is a constellation of low-earth orbiting satellites that provide voice and data services. Iridium was first decoded with low cost hardware by security researchers back in 2016 as mentioned in this previous post. Being unencrypted it is possible to intercept private text and voice communications.

Rob's video is part of a series, and so far only part one has been uploaded. The first video outlines the hardware and software requirements for Iridium decoding and demonstrates the gr-iridium software. An Airspy and RTL-SDR Blog Patch Antenna are used for the hardware, and the software runs on DragonOS.

Rob writes that in part two he will demonstrate the use of iridium-toolkit, which can be used to extract data and recordings from the Iridium data provided from gr-iridium.

Be sure to subscribe to his YouTube channel so that you are notified when part two is released.

Iridium Satellite Decoding Part 1: The Tutorial That Goes Over Your Head, Literally!

Tech Minds: Introducing the SDRplay RSPdx-R2 and SDR Connect Preview 3

At the end of last week, we posted how SDRplay released the RSPdx-R2, an updated version of their RSPdx product. Recently Matt from the Tech Minds YouTube channel received his RSPdx-R2 and has uploaded a video comparing the RSPdx-R2 to the previous model. His results show that the new model has an improved lower noise floor, resulting in signals with higher SNR. 

In his tests, Matt uses the SDR Connect Preview 3 software. This is the latest version of SDRplay's new custom multiplatform software that they are developing. While testing the RSPdx-R2, Matt allows shows some of the new features in SDR Connect Preview 3, including a new Audio peak hold graph, FM MPX view, and a new frequency manager.

Introducing The New SDRPlay RSPdx R2 & SDR Connect Preview 3

SDRplay RSPdx-R2 Released

SDRplay has announced the release of their latest product, the SDRplay RSPdx-R2. The RSPdx-R2 is advertised as an enhanced version of their RSPdx software-defined radio. The press release from SDRplay reads:

Jon Hudson, SDRplay Sales and Marketing Director said “Global supply chain support issues have prompted some redesign of existing products to ensure continued supply for our UK manufacturing partners. With each new member of the RSP family, SDRplay tries to include improvements. This has given us the opportunity to offer performance enhancements at the same time as assuring supply”.

  • The RSPdx-R2 provides up to 10MHz spectrum visibility anywhere from 1kHZ to 2GHz with no gaps. It features:
  • Improvements to the RSPdx for MF frequencies and below:
    • Improved noise performance below 1MHz
    • Improved dynamic range below 2MHz both in tuner mode and HDR mode
  • 3 Software selectable inputs, including a BNC input for up to 200MHz
  • A 500kHz LPF for LF/VLF
  • HDR mode for enhanced performance under 2MHz
  • Notch filters on all inputs
  • A rugged steel case

More details on https://www.sdrplay.com/rspdxR2/

The suggested retail price is £188.00 GBP (excluding VAT), $235.00 USD (excluding tax) or €225.60 EUR (excluding tax).

SDRplay recently launched their free multiplatform SDRconnect software which as well as running on Windows, will also run on MacOS and Linux/Raspberry Pi. As with their SDRuno windows software, the emphasis is on “plug and play” making the SDRplay receivers an easy-to-use and low-cost way to discover (or rediscover) the radio hobby for anyone who already uses a computer.

SDRplay has also provided the datasheet of the RSPdx-R2 which can be downloaded here.

The new RSPdx-R2
The new RSPdx-R2
Introducing the SDRplay RSPdxR2