Radio Hacks

1525 Articles

From Phone, To SDR, No Extra Hardware

November 9, 2026 by 21 Comments

One of the more exciting recent developments has been the discovery that many radio chips used in common and cheap wireless network interfaces, microcontrollers, LoRa interfaces and others can be persuaded to give access to their baseband data streams This gives them full SDR functionality, which on cheap devices is hugely interesting. Continuing that trend and taking it to a new height is [Logan Zarov], who’s converted an LG D325 Android phone into a wideband receiver with very minor modification indeed.

The phone is rooted and runs LineageOS as you might expect, and there’s a modem firmware update to supply the SDR baseband magic. There’s also a mod for an antenna wire. Where this becomes especially interesting is in its receive frequency range. The modem talks in the GHz, but this radio receives in the MHz, it can pick up shortwave. This is achieved by using the Bluetooth radio as a local oscillator, oddly in a similar manner to that we suggested a few weeks ago.

This is hackery at its most epic, we love it, and look forward to the similar hacks which will certainly follow. There’s a video below the break, and you can see it doing its thing.

Continue reading “From Phone, To SDR, No Extra Hardware” →

Active Antenna Runs On A Single Lithium-Ion Cell

November 7, 2026 by 11 Comments

[skuep]’s Mobile-Whip is a compact, active receive-only antenna that is optimized for operation from a single lithium-ion battery or USB power. This makes it very handy for use on portable equipment, as shown in the images here.

What’s an active antenna do? Its main purpose is to provide useful reception with an antenna size much smaller than would normally be called for. It’s pretty handy to be able to have one that’s completely self-contained, and able to easily fit on a mobile radio or scanner.

The Mobile-Whip is based on the Mini-Whip active antenna by [PA0RDT], but with some important changes. One is that it has a narrower frequency range, but it’s also one piece, much smaller, can be powered by a single lithium-ion cell, and it integrates a charger.

It’s still in early development (and there’s no enclosure designed yet), but if you’d like to try it out for yourself the schematics and KiCad files are available. There are also instructions for ordering everything from a PCB manufacturer, which is about as easy as it gets.

[skuep] seems to have a knack for designing PCBs that attach directly to portable equipment, like the Ham Radio All-in-one cable (AIOC) which makes interfacing to a computer ridiculously easy.

The Hidden Microcontroller Inside A LoRa Chip

November 7, 2026 by 15 Comments

If you’ve ever done anything with LoRa, the chances are you’ve used a LoRa chip or module as a peripheral for a microcontroller, and left it at that. But that’s not always the case. Rather than being a pre-programmed ASIC under the hood, the Semtech LR2021 has its own on-board microcontroller whose firmware can be updated. [Alex Beale] has managed to unlock its secrets.

The use of LLMs can elicit strong opinions at times, but in this case we agree with him that the task of reverse engineering this hidden microcontoller would have been a near-impossible task without their help. Having done so though,he can write custom firmwares, which he’s able to demonstrate. Running the required FFTs for a waterfall display on-chip for example is now possible, as is running your mesh network node on the chip itself.

This work continues a streak of recent discoveries unlocking software-defined radio functionality inside dedicated radio chips, with both WiFi and LoRa chips falling prey to reverse engineering. It’s an interesting time, if SDR is your thing.

Thanks [Notbasa] for the tip.

Building An ADS-B Receiver For Less Than You Think

November 1, 2026 by 5 Comments

If you’ve ever wondered about the planes flying above your head, you could always listen in to ADS-B transmissions to learn more about them. [thefatmoop] has built a rig to do just that, and it comes in under $50 in parts.

The build is based around the Meshnology W12 board, which combines an ESP32-S3 microcontroller with an LR2021 LoRa Radio. The latter is able to be tuned into transmissions in the realm of 1090 MHz and it can capture ADS-B traffic that uses OOK and Manchester encoding. The data is passed to the ESP32-S3 which validates the CRCs of the captured data and serves up the aircraft tracks on a simple web interface. A GNSS receiver can also be added in so the board knows its own location as well as the location of the planes that it’s tuning in.

[thefatmoop] reports decent performance with the rig, pulling in aircraft tracks from up to 150 nautical miles away using a 915 MHz antenna. There are some mods required to achieve this performance, though—namely, you’ll want to modify the filter configuration on the board to avoid it attenuating the 1090 MHz signals of interest.

There are lots of other ways to listen to ADS-B signals, too—you can always grab yourself an SDR and get going. If you’re cooking up your own cheap radio hacks, don’t hesitate to let us know on the tipsline!

Thanks to [Moser] for the tip!

Hacking A Marine Radio Dish

October 27, 2026 by 14 Comments

Having watched some fun videos on repurposed satellite dishes on YouTube, [Melan] wanted to get in on the action, managed to source an Intellian i4 — a dish built for marine use — and set about hacking it.

[Melan] first needed to convince the antenna that it was still on a boat by using an RP2040 microcontroller and an RS-422 module to send NMEA sentences. This was necessary to tell the i4 the “heading” of the “boat”, even though [Melan] was really using the rig stationary on land. From there, a simple email to the company itself sufficed to get the Intellian software running on the antenna.

But could it be controlled without the software?. Sniff the communications between the software and the Antenna Control Unit, and decompile the code. This done, it was relatively straightforward to put together a protocol description and figure out how to command the antenna where to point simply by issuing commands for azimuth and elevation.

We’ve featured other great bits of satellite equipment before, like this truck tracker teardown from a few years ago. If you’ve got some nice equipment on the bench that listens in on (or transmits out to) birds in space, don’t hesitate to let us know on the tipsline.

Simple, Reliable RF Remote Control

October 25, 2026 by 29 Comments

Some of the first remote controls available to consumers used sound, visible light, or even just wires to communicate with their parent device. It was many years between these first rudimentary remotes before they standardized around infrared or RF signaling. Even then it was a while before remote controls were reliable enough to not have to think about anymore. They’ve gotten so good now that there are small modules available that let us quickly build these devices to perform all manner of tasks.

[Igor Brichkov] is demonstrating this project because his garage door remote control suddenly stopped working. The RF receiver and transmitter circuits are readily available and inexpensive, but they need some support circuitry to work properly. The transmitter is paired with an encoder which is provided a binary code by wiring various pins to power and ground. This “code” is sent to the receiver which has a decoder and listens for that specific code. When the codes match it changes the state of one of its pins, which is used in this case to short the garage door’s remote terminals and signal it to open the door.

Although the resulting handheld remote with its single button looks a bit like something from 1950s science-fiction, it’s an effective solution. Especially when compared to possibly trying to reprogram a proprietary remote, find one from a company that doesn’t exist anymore, or rebuild one that operates on a bizarre frequency. With access to the physical hardware, it turns out a lot of things are controlled by just shorting pins together, and anything can do that from wires to RF transmitters.

Continue reading “Simple, Reliable RF Remote Control” →

Four black plastic devices, two with a black, stubby antenna, sit on a blue cutting mat with white guidelines. There is also a PCB and a couple grey-ish clips in the assortment. One of the devices is open, showing another PCB with various components including a GPS antenna and LoRa radio. A silhouette of a dog is screen printed next to the text "LIA" on the PCBs, and the same text and image is present in the shell of the device in the top center.

Meshtastic Pet Tracking

October 25, 2026 by 15 Comments

Most commercial pet trackers require a subscription or network connection to function. [Jon G Aguado] wanted a better way and designed LIA, a Meshtastic collar tracker.

LIA uses a custom PCB containing a ESP32-S3, LoRa radio, GPS/GNSS receiver, and a charge controller for the 18650 or 5023450 pouch Li-ion cell powering the device. Everything fits inside a 3D printed enclosure, and the device is charged via a magnetic 4-pin USB pogo connector to increase weather resistance.

One of the neat features of this particular tracker is that [Aguado] gave it two different power modes. High power gets a location fix every 30 seconds and has a pair of bright LEDs for visual assistance, low power only gets a fix every minute or so, and it can also be set to off, which is something we wish more device manufacturers remembered should be an option.

We hope anyone planning on using Meshtastic and LoRa in the US is aware of the issues surrounding FCC compliance, and if you want to track your pet another way, maybe KineFox is an option?