Tagged: rtl-sdr

Running RTL-SDR in your Browser via an HTML5 App

Thank you to Jacobo Tarrio for writing in and sharing his latest project, an HTML5-based RTL-SDR application that runs directly in your browser. Jacobo writes that he'd previously created a Chrome app called FM Radio Receiver for Chrome (which we also posted about previously), but unfortunately, Google stopped supporting Chrome apps.

Jacobo goes on to write:

Last year I started working on it again. I took the original source code, modernized it to use modern TypeScript and HTML5 APIs, and then transformed it deeply to turn Radio Receiver into a general-purpose RTL-SDR application (with a waterfall and everything), which is available at https://radio.ea1iti.es/.
 
You don't need to install anything -- it runs straight on your browser. (Well, you still need to do the usual RTL-SDR driver setup, but other than that...)
 
It supports any computers or Android phones with the Chrome, Edge, or Opera browsers. Unfortunately, it cannot run on iPhone or iPad, or on the Firefox or Safari browsers.
 
For hardware, it works well with the RTL-SDR Blog V3 and V4 sticks (with support for direct sampling on the V3 and for the built-in upconverter on the V4), as well as other R820-based sticks.
 
The source code is available on GitHub under the Apache 2.0 license.
RTL-SDR running in an HTML5 web browser app
RTL-SDR running in an HTML5 web browser app

Updates to Knowle Consultants RTL-SDR Android Apps

Thank you to James Mainwaring, who wanted to write in and share that he has made some updates to his suite of Android apps, which include ADS-B Radar (RTL-SDR), FM Radio (RTL-SDR), Airband Radio (RTL-SDR) and HAM FM Radio (RTL-SDR).

James notes that all his apps now support the ability to connect to an rtl_tcp instance running remotely. He also writes that the ADS-B app now automatically downloads and displays photos of the aircraft being tracked via the API connection to planespotters.net.

ADS-B Radar (RTL-SDR) Android App now shows aircraft images.

DragonBridge: Streaming IQ Data Over 802.11ah HaLow via Two Relay Drones

Aaron, creator of DragonOS, has uploaded a video on his YouTube channel showing him testing out long-range communications via 802.11ah Wireless Networking and a T-HaLow bridge on two drones. 802.11ah (aka HaLow) is a WiFi protocol designed for long range IoT communications of up to 1 km (without obstructions).

In the video, Aaron attempts to stream IQ data with SDR++ over 802.11ah HaLow from a Pi + KrakenSDR operating over 1.6km away. The communication is established via two drones in the air that act as a relay bridge between the two ground stations. Although there are issues with keeping the connection stable, these experiments serve as a great first test of this capability.

Join me on an exciting month long+ journey as I push the boundaries of wireless communication using the Lilygo T-HaLow 802.11ah devices in bridge mode! In this video, I demonstrate how I successfully established an SSH connection from my laptop, across six T-HaLow units—some mounted on two drones and others on the ground—to a Raspberry Pi ground station equipped with DragonOS pi64 and a KrakenSDR.

What You'll See:

Innovative Network Setup: I configured three pairs of T-HaLow units, each pair consisting of an access point and a client. The first pair connected my laptop to the first drone. On each drone, I bridged two T-HaLow units via Ethernet, effectively creating a relay system. The second pair connected the two drones, and the third pair linked the second drone to the ground station Raspberry Pi.

Successful Long-Distance Communication: By the third attempt, I achieved a stable ping across the entire bridge and streamed IQ data from the SDR++ server on the Raspberry Pi to the SDR++ client on my laptop—over a distance of 1.6 km between drones!

Challenges and Triumphs: Experience the hurdles I faced, from connectivity issues to environmental obstacles, and how perseverance led to a successful connection.

Stunning Aerial Footage: Enjoy breathtaking drone shots that not only showcase the technology but also add a visual treat to the technical journey.

Why This Matters:

This project highlights the potential of increasing the standoff distance between equipment using 802.11ah technology, also known as Wi-Fi HaLow. Operating in the sub-1 GHz unlicensed bands, 802.11ah offers extended range and improved propagation through obstacles compared to traditional Wi-Fi frequencies. It's designed for low-power, long-range connectivity with lower power consumption—ideal for IoT applications, remote deployments, and innovative projects like this DragonBridge.

Equipment Used:

Building the DragonBridge: Long-Range 802.11ah Wireless Networking with Drones and T-HaLow Devices

A Tutorial on Setting up a XHSI Cockpit Display with Live Data from an RTL-SDR Receiving ADS-B

Back in 2017, we first posted about using a program called RTL1090-XHSI which is used to display a simulated aircraft cockpit using live data acquired directly from an RTL-SDR receiving ADS-B flight data from nearby aircraft. The ADS-B signal provides not only position and heading data but also information about altitude and speed, which is then used to simulate the cockpit display.

Recently Al wrote in and wanted to share with us a step-by-step tutorial that he has created that shows how to set this up. The guide shows how to download, install and use all the software programs required.

XHSI Cockpit Display with Live ADS-B Data Received by an RTL-SDR
XHSI Cockpit Display with Live ADS-B Data Received by an RTL-SDR

Receiving Starlink Signals with an RTL-SDR and Ku-Band LNB

Over on YouTube, dereksgc has uploaded a new video showing how to receive signals from Starlink satellites using an RTL-SDR and a standard Ku band LNB. Note that this setup simply receives the raw signals, and it does not allow you to connect to the Starlink service.  

In the video, dereksgc first introduces Starlink satellites and explains what signals they transmit, referencing a paper on the structure of the Starlink Ku-band downlink by researchers at the University of Texas. He notes that the signals are strong enough that a single LNB without a dish is sufficient for receiving them. An LNB is a feedhorn antenna, low-noise amplifier, and downconverter all-in-one. It converts the ~10.950 GHz Ku band signal of the Starlink satellites down to a frequency that the RTL-SDR can receive.

In the rest of the video, he shows a timelapse of signals being received. The signal's doppler shift can be seen and heard as the satellite passes over.

Receiving Starlink signals with RTL-SDR

PySpecSDR: A Text User Interface Based Python RTL-SDR Spectrum Analyzer and Signal Processor

Over on GitHub a new open-source program called 'PySpecSDR' by [xqtr] has recently been released. This is a full multipurpose SDR receiver program like SDR# or SDR++, but with the difference that it runs entirely with a text user interface.

PySpecSDR displays a real-time spectrum and waterfall via text user interface and has the ability to demodulate and play audio for FM, AM, and SSB signals. The software also includes features like a scanner, automatic signal classification (between digital, FM, AM), frequency bookmarks, AGC, recording capabilities, band presets, and a configurable display. It is completely controlled via keyboard shortcuts.

Currently, the first version supports RTL-SDR only, but there is another version being worked on in the repo called pyspecsdr-soapy.py. This version uses SoapySDR, and that should support almost every SDR. It appears that most SDRs should already be working, but there are still some quirks to be fixed.

Some PySpecSDR Screenshots
Some PySpecSDR Screenshots

A SDR++ CSV to JSON Frequency Bookmark Converter Python Script

Thank you to RTL-SDR.COM reader Steve Hagerman for writing in and sharing his Python script that allows SDR++ users to convert a CSV file of frequency bookmark information into a JSON file that SDR++ recognizes. Steve explains:

[In SDR++] one of the biggest issues is in making frequency bookmarks. SDR++ uses a JSON file to store frequency bookmarks which is hard to edit manually. While there is a direct means to enter bookmarks directly in SDR++, it is tedious and requires too many mouseclicks.

To fix this I wrote a Python script to take easily made XLSX Spreadsheet of frequencies to convert to a JSON file that can be used directly with SDR++.

Steve's CSV to JSON Python Script Flow Graph
Steve's CSV to JSON Python Script Flow Graph

The Design and Test of a Filtered Low Noise Amplifier for LRPT Weather Satellite Reception

Recently Salil (aka NUCLEARRAMBO) uploaded a blog post on his website detailing how he designed and tested a low noise amplifier (LNA) with a filter for 130 - 160 MHz, which is useful for improving reception for the Meteor M2 LRPT weather satellite. If you were unaware, an LNA can help improve the reception of an SDR by reducing the noise figure of the system, and by overcoming losses from long coax cable runs. The filter helps reduce the strength of out-of-band signals which if too strong, can desensitize and cause imaging on the RTL-SDR.

In his design, Salil used a PGA-103+ LNA chip which has excellent noise figure and OIP3 specifications. His blog post details how he designed the circuit around the PGA-103+, added a bias tee for power, and how he designed the filter.

In part 2 of his post, he details how he tested the LNA+filter combinations frequency response, input voltage range, noise figure, and bias tee with an RTL-SDR Blog v3 and a NanoVNA V2.

Salil's low noise amplifier
Salil's low noise amplifier