https://kylavara.fi/toiminta-hairiotilanteissa/tiedonkulun-varmistaminen/kylaradio/

If you’re a collector of older TVs, you’re probably facing the problem in some form of having no transmissions to tune in to. With many sets you can use a SCART or other A/V input, but nothing beats using the thing as it was intended. [BorisDigital] had exactly this problem, and since he worked in a TV transmitter control room in the 1990s, he’s made a small TV station that looks and operates like the real thing.

It’s a 10 inch rack stuffed with goodies, each of which replicates the function of a piece of broadcast gear which would have cost a small fortune back in the day. At the top is a transmitter, a relatively inexpensive board from China. Below it a clock and audio monitor powered by a Pi Pico, then a vectorscope, waveform monitor, and monitor powered by a set of Pi 5s with USB video digitisers, a pair of SD card video record/play units — yet more Raspberry Pi — and at the bottom, an automatic scheduler powered by another fruity board from Cambridge. If you’re not into TV the construction may be worth a second look. Those neat looking rack front panels are 3D printed with different filaments for the lettering, and are both robust and stylish. We can already see how this could be used in our work.

https://www.youtube.com/watch?v=dvhU6qKurbk

If you’ve been on the RTL-SDR forums lately you may have seen that a lot of work has been going into the DragonOS software. This is a software-defined radio group that has seen a lot of effort put into a purpose-built Debian-based Linux distribution that can do a lot of SDR out of the box. The latest and most exciting project coming from them involves a method for using the software to receive and demodulate analog video.

Decoding 5GHz NTSC Video from Drones with a HackRF, DragonOS and SigDigger
https://www.rtl-sdr.com/decoding-5ghz-ntsc-video-from-drones-with-a-hackrf-dragonos-and-sigdigger/

With the ESP32 series of microcontrollers having had hidden software-defined radio (SDR) facility revealed, we’re now moving on from the announcement into projects making use of the finding. [Twotoz] has one using an ESP32-C5, to receive and demodulate analog FM video.

You might think that video is something which has largely gone away in 2026, with TV transmissions having made the switch more than a decade ago, and home entertainment appliances having used HDMI for longer. But it’s still very popular in the world of drones however, where it exists as 5 GHz FM transmission.

Analog 5.8 GHz FPV receiver on one Seeed Studio XIAO ESP32-C5 with a passive 6-bit resistor DAC: live FM video in, composite PAL/NTSC out for goggles.
https://github.com/Twotoz/C5VRX

C5VRX-5 uses one live demodulator.

U85Q demodulator in the TX BitScrambler: an untrained 32-phase tracker that keeps the picture locked across VTX deviations, off-centre carriers and multipath instead of dropping out. Board-validated on real video.
Fixed ultrafine IQ (ADC bits 9,6,5,4) at 40 MS/s, no CPU in the sample path.

To quote commenter [douyarou], “It’s like our little version of a Precambrian explosion”. A bunch of hackers have discovered, independently and building on each other’s work, software-defined radio (SDR) capabilities in more places than you can shake a stick at.

It all started with [Espargos] and [h0m3us3r] apparently independently discovering that the ESP32 family of chips had a “secret” debug mode that allowed direct access to the radio that’s normally used for WiFi. While the 2.4 GHz radio signal is almost always immediately converted into data by the MAC hardware, here they found a way to listen in upstream, to the raw IQ data.

Since the discovery of an undocumented I/Q sampling feature in ESP32 chips about two weeks ago, there’s been a flood of similar features being found in other wireless chips, including LoRa and Wi-Fi chipsets. The latest chip to join their ranks is the MediaTek MT7921AU, often used in Wi-Fi adapters, with two different projects developing independent SDR drivers for it in the last few days.

The first was BirriaSDR, which discovered that the chip exposes raw I/Q samples for debugging and calibration; BirriaSDR instead streams these to the host at 40 Msps in 14-bit resolution, with the option to tune from 2156 to 2610 MHz. BirriaSDR uses libusb to directly communicate with the Wi-Fi adapter and access its registers; it doesn’t make any permanent firmware changes, so the Wi-Fi adapter goes back to its original state after being used as an SDR. BirriaSDR implements an API similar to the RTL-SDR’s.

Mtk79ICAP, by contrast, exposes the MT7921AU’s sampling features over a standard SoapySDR interface. Unlike BirriaSDR, it applies some firmware changes to the chip, and it requires a modified driver to work.

https://github.com/luigifcruz/birriaSDR

BirriaSDR

Turn a supported USB Wi-Fi dongle into an experimental SDR receiver with 14-bit I/Q at 40 MSps complex.

BirriaSDR ships as libbirriasdr, a C11 library with an API modeled on librtlsdr, together with a command-line recorder. It talks to the device from userspace through libusb and includes the source of its own small device program. Start with Build and try, or jump to the API to add the receiver to an application. To see it working without building anything, try the rough proof of concept.

Important

This is experimental software. The tested board starts from a channel 6 initialization profile, and the library can tune anywhere from 2156 to 2610 MHz. Sensitivity across that range, frequency accuracy and gain are not calibrated. Use at your own risk.