Proposing a Software Defined Radio based “AI Battle Buddy”

Over on YouTube, Isaac Botkin of TREX LABS has uploaded a video discussing how he proposes to build an "AI Battle Buddy" with a built-in software-defined radio. The idea is to combine a wide frequency range software-defined radio with AI tools that automatically determine and alert the device owner when something interesting occurs in the radio spectrum.

Isaac gives example use cases for the device, such as alerts when jamming is detected, drone detection alerts, alerts when there is suddenly increased public safety radio traffic or if there are nearby public safety radio transmissions, and information about nearby aircraft and NOAA weather alerts.

The device is proposed to have no screen, but would simply give audio alerts via Bluetooth earpiece, or text alerts via smartphone or smart watch. 

Ultimately, such a device has yet to be built for the general consumer market, but Isaac notes that AI-SDR devices like the Anduril Pulsar already exist for the military consumer.

How to Make an AI Battle Buddy for Electronic Warfare

Using our RTL-SDR Blog Dipole as a V-Dipole for Receiving Weather Satellites

With our RTL-SDR Blog dipole antenna set, it is possible to use it in a "V-dipole" configuration to receive polar-orbiting weather satellites such as NOAA and Meteor at 137 MHz. More information on this can be found on our page at www.rtl-sdr.com/DIPOLE.

If you are after more visual instruction, "Baltic Lab" has uploaded a clear video on YouTube showing how to set the dipole leg lengths and angles correctly for weather satellite reception. 

We want to add that it is also important to remember to mount the antenna outdoors horizontally and in a north-south orientation with a clear view of the sky for the best results.

How To Build A V Dipole For Receiving Weather Satellites

IEEE Spectrum Article on Discovery Dish

Electrical engineering magazine IEEE Spectrum has recently posted an article about our Discovery Dish product, which was successfully crowd-funded on CrowdSupply and delivered to initial backers early this year. Discovery Dish is a 70-cm aluminum satellite dish with an active filtered feed. It is designed for receiving real-time weather data from GOES HRIT, GK-2A LRIT, FengYun LRIT, NOAA HRPT, Metop HRPT, Meteor M2 HRPT, and other weather satellites that operate around 1.69 GHz. There are also feeds for Inmarsat satellites, Hydroden Line observation, and S-band satellites.

In the article, Stephen Cass introduces the Discovery Dish, highlighting its practical uses and the convenience of disassembling it for easy packing in a suitcase during travel. He also shares his experience using the Discovery Dish to successfully receive images from the GOES-East satellite from the rooftop of his New York City apartment.

Finally, he mentions how he tested the hydrogen line feed as well, successfully seeing a hydrogen line peak when pointing at the galaxy.

Image from the IEEE Spectrum Article on Discovery Dish
Image from the IEEE Spectrum Article on Discovery Dish

ADALM PlutoSDR Spectrum Analyzer: Sweep from 100 MHz to 6 GHz

Thank you to RTL-SDR.COM reader Maka for sharing his latest software for the ADALM PlutoSDR, "ADALM PlutoSDR Spectrum Analyzer." The software is a sweeping spectrum analyzer that uses the 'lock-in amplifier techniques' and it allows you to view the entire 100 MHz to 6 GHz tuning range of the PlutoSDR.

The program is an open-source MIT-licensed Python script that can be run on Linux systems. Instructions to install and connect to the PlutoSDR are available on the program's GitHub page. Maka has also provided a YouTube video (embedded below) demonstrating the software and explaining the lock-in amplifier technique used in his software, as well as two other videos, one explaining the code, and another showing how to measure a filter with it.

Maka writes:

I built an open-source real-time spectrum analyzer using the ADALM Pluto SDR and Python. It allows you to sweep across wide frequency ranges (100 MHz to 6 GHz) and visualize RF signals like Wi-Fi, LTE, GSM, and Bluetooth in real-time.

It includes a custom PyQt GUI with:

  • Adjustable sweep parameters
  • Peak hold
  • Threshold alerts
  • Draggable markers
  • Highlighted known bands
  • Data export to CSV
See Invisible Electromagnetic Waves Around You with ADALM Pluto SDR Spectrum Analyzer + Code

Spectrum SDR: New Android App for RTL-SDR FM/AM Decoding and Spectrum Viewing

Thank you to James Mainwaring of Knowle Consultants for submitting news of the release of his latest Android app called "Spectrum SDR" for RTL-SDR. Knowle Consultants have previously released a range of RTL-SDR Android apps for FM, Airband, Ham FM and ADS-B reception. The new Spectrum SDR app has a spectrum viewer, as well as the ability to demodulate AM and FM signals.

James writes the following about Spectrum SDR:

This application is about having a bit of fun with those amazing little RTL-SDR dongles, whilst listening to AM/FM radio signals. It's nice and easy to use so why not give it a try?

- Covers the full frequency range of your RTL-SDR dongle
- AM and FM, wide and narrow
- FFT display
- Sample rates 240000 Hz to 2160000 Hz
- Bias tee control
- 75 presets over 5 pages
- Gain controls
- Squelch
- Built-in help

Spectrum SDR Android App Screenshot
Spectrum SDR Android App Screenshot

TechMinds: Testing out the SDRBerry Software on a Pi 4 with Touchscreen

Over on the TechMinds YouTube channel, Matt has posted a video demonstrating the SDRBerry software, which can be used with many SDR devices, including the RTL-SDR, on a Raspberry Pi with a touchscreen.

The SDRberry software is designed to be used on a touchscreen. As Matt points out, it has an aesthetically pleasing user interface and is compatible with almost any SDR software via the Soapy interface. Combining an SDR with a Pi 4 touchscreen and SDRberry results in an excellent hand-held SDR system.

In the video, Matt demonstrates the features of SDRberry, showing its RX features as well as some of its TX features, such as speech transmission and FT8, via a built-in WSjtx tab. He then shows the optional web interface, which is still in the early stages of development. Finally, he shows how to install the software and dependencies onto a fresh Raspbian image. 

SDRBERRY - This User Interface Is Just GORGEOUS! AND IT USES SOAPY TOO!

Khanfar Spectra-All: Combine Multiple SDRs into a Wideband Spectrum Analyzer Display

Over the past few weeks we've posted about the release of multiple Windows software programs from M. Khanfar an SDR hobbyist who has begun developing new software for the RTL-SDR and other SDR devices. He's released a Spectrum Analyzer and FM demodulator, directional antenna based radio direction finder, and a gr-phosphor based spectrum visualizer.

Recently, M. Khanfar has released a new Windows program called "Khanfar Spectra-All" which is a gr-phosphor based spectrum analyzer that can combine the bandwidths from multiple SDR devices, including RTL-SDR, Airspy and, HackRF SDRs into a wideband display.

Khanfar writes:

Control all connected SDR devices through a single unified interface. No manual alignment needed - devices automatically position frequency ranges to maintain continuity.

Seamless Spectrum Coverage: Create ultra-wideband monitoring setups that exceed capabilities of any single SDR. Ultra-fast frequency scanning with dwell times as low as 8ms for rapid spectrum sweeps.

Uninterrupted visualization across device boundaries. See all connected SDRs in a single, coherent display. Software automatically detects, initializes, and synchronizes all available SDR hardware on startup. All connected SDR devices function as a single block during scanning operations.

Customize dwell time, frequency steps, and range to optimize for specific monitoring needs. Handles the complexity of coordinating multiple SDRs, presenting a unified interface.

Frequency Locking Across Multiple SDR Instances: Creates a continuous spectrum view by intelligently aligning frequency ranges of all connected devices.

One-Control Operation: Control all connected SDR devices through a single interface with synchronized parameter adjustments.

Turbo Scanning with 8ms Dwell Time: Ultra-fast frequency scanning capabilities for rapid signal discovery.

GPU-Accelerated Visualization: Uses Fosphor, a high-performance GPU-based spectrogram engine, for smooth real-time rendering.

The latest version 1.2 of Khanfar Spectra-All also adds a mobile web interface that can be used to control the settings of the SDRs remotely.

As mentioned in previous posts, antivirus software can flag M. Khanfar's software as suspicious. We suspect these are false positive results due to the PyInstaller system used to create the exe, but please take your own precautions just in case.

Khanfar Spectra-All

rtl_icecast: A Terminal Application for Streaming FM to an Icecast Server with RTL-SDR

Thank you to Jouni (OH3CUF) for submitting news about the recent release of his new Linux terminal based open-source software called 'rtl_icecast', which can be used with an RTL-SDR to stream FM audio to an Icecast server.

Icecast is an open-source streaming media server that broadcasts audio and video streams over the internet.

Jouni writes:

rtl_icecast is a shell native application that uses RTL-SDR to receive FM radio signals and stream them to an Icecast server in MP3 format.

The main target usage for this app is to stream your local HAM FM repeater audio to your public shoutcast/icecast server with just a RTL-SDR USB-receiver and for example Raspberry Pi. It can be used to stream broadcast FM too, of course.

The app is native app and uses the RTL-SDR on hardware level directly. No need to pipe or install anything extra. This works out of the box (well, I hope!)."

A block diagram of how the rtl_icecast streamer works
A block diagram of how the rtl_icecast streamer works