Building a ‘WiFi Camera’ with a HackRF and Helical Antenna on a Motorized Pan-Tilt Mount

Recently, "The Thought Emporium" YouTube channel uploaded a video showing how they have created a 'WiFi Camera' using a HackRF and helical antenna mounted on a motorized Pan-Tilt mount.

The Thought Emporium has actually already done this experiment back in 2018, as seen in a previous post; however, in the latest video, they iterate on the design, releasing a new open-source 3D printable version.

The idea behind the 'WiFI camera' is to point the directional helical antenna in different directions using the motorized mount and measure the WiFi signal power using the HackRF at each spot it points towards. Each measurement results in a heatmap pixel, and once enough pixels have been collected, an image is formed.

This Camera Can SEE WiFi

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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

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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
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HOPE XV Conference 2024: Ham Radio for Hackers Talk Video

Back in July 2024 we posted about Dan's (KB6NU) talk at the HOPE (Hackers of Planet Earth) conference about how Ham radio can be for hackers, and how hackers are the future of ham radio. Back then only the slides were available.

The video of the talk has recently been uploaded to YouTube, and is embedded below. The talk emphasizes how ham radio is not only about the traditional thought of making contacts, which is probably in most people's heads, but also about hacking radios, antennas, microcontrollers, satellites, pico balloons, digital communications, GNU Radio, and more. Dan mentions his goal is to promote ham radio to the much younger hacker crowd, where he believes it is underrepresented.

HOPE XV (2024): Ham Radio for Hackers

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Creating an SDR from a TEF6686 Car Radio FM/AM Chip

A recent IEEE Spectrum article details how hobbyist PE5PVB has repurposed an NXP TEF6686 automotive FM/AM tuner chip into a software-defined radio with a tuning range of 65 MHz - 108 MHz and 144 kHz - 27 MHz.

PE5PVB developed custom open-source firmware for TEF6686 dev boards, allowing them to tune beyond their original design frequency range. He then went on to develop a version that included a screen. Eventually, the Chinese manufacturers caught on to the potential of the design and are now producing a full handheld version that is available on Aliexpress at a current sale price of US$61.26.

Reviews of the product are all positive, and it appears to be one of the best choices for a portable handheld DXing radio.

A TEF6686 based SDR available on Aliexpress.
A TEF6686 based SDR available on Aliexpress.
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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

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TechMinds Reviews the Recently Released SDRplay nRSP-ST Networked Software Defined Radio

OPver on his TechMinds YouTube channel Matt has uploaded a review of the SDRplay nRSP-ST networked software-defined radio which was released for sale just last week at a retail price of US$499.95.

A networked SDR like the nRSP-ST allows the user to set up the radio in a remote location, and easily connect to and use it remotely over a local network or internet connection. Similar devices include the KiwiSDR and Web-888 and of course, it is possible to achieve something similar with other SDRs that provide server software using a device like a Raspberry Pi as the server.

Matt first unboxes the nRSP-ST in the review and compares it in size to the RSPdx, noting it is about double the size. He then goes through all the I/O ports on the device, pointing out that it has an WiFi connector, Ethernet port, reference in, two SMA antenna connections for 1 kHz to 2 GHz, and one BNC for 1 kHz to 200 MHz.

Matt then opens the nRSP-ST's lid, exposing the circuitry. He notes that it has a 1.5 GHz quad-core processor, 2GB RAM, 8GB eMMC, and the SDRplay radio circuitry. The computing hardware is covered by a soldered-down metal shielding can, but from the specs, we note that it sounds like a Raspberry Pi Compute Module 4 is used under the hood.

In the rest of the video, Matt shows how the remote software can be set up and updated. He then goes on to show the SDR Connect and browser-based software being used to receive signals with the nRSP-ST.

NEW! SDRPlay nRSP-ST Networked Software Defined Radio Receiver - Hands ON!

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Open-Weather APT: Updates to the Web Based NOAA APT Image Decoder

Dr. Sasha Engelmann and Sophie Dyer, the team behind the Open-Weather project have recently announced the launch of their new version of open-weather apt, a web-based NOAA APT image decoder. The web-based program accepts a WAV file containing a NOAA satellite APT recording, demodulates and decodes it, and displays the resulting weather satellite image.

Sasha writes:

In our recent newsletter, we summarised the updates as follows:

Open-weather apt is the only public, maintained, browser-based decoder for Automatic Picture Transmissions (APT) from satellites NOAA-19, NOAA-18 and NOAA-15. It was developed to improve access to satellite signal decoding for all practitioners.

We are excited to share a new and improved version available here! The new version includes the following updates and additional features:

  • Improved accuracy in decoding and finding sync positions (locates more sync positions than other comparable decoders)
  • Upload a WAV file of any sample rate (no more re-sampling with Audacity!)
  • Option to see the ‘raw’ image without syncing, and to ‘Find the Syncs’
  • Option to Rotate 180 degrees, often useful for viewing images from nighttime passes
  • Go deeper in your analysis: explore Signal Value and Image Value Histograms
  • Upload directly from open-weather apt to the Public Archive

Open-weather apt is co-developed by open-weather with Rectangle (Lizzie Malcolm and Dan Powers), Bill Liles (NQ6Z) and Grayson Earle. We have had a lot of fun testing and experimenting. Please let us know if you have feedback!

Open-Weather APT Web Decoder
Open-Weather APT Web Decoder
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