Receiving Radio Signals From Space Like It’s 1994

August 28, 2025 by Bryan Cockfield 19 Comments

For certain situations, older hardware is preferred or even needed to accomplish a task. This is common in industrial applications where old machinery might not be supported by modern hardware or software. Even in these situations though, we have the benefit of modern technology and the Internet to get these systems up and running again. [Old Computers Sucked] is not only building a mid-90s system to receive NOAA satellite imagery, he’s doing it only with tools and equipment available to someone from this era.

Of course the first step here is to set up a computer and the relevant software that an amateur radio operator would have had access to in 1994. [Old Computers Sucked] already had the computer, so he turned to JV-FAX for software. This tool can decode the APT encoding used by some NOAA satellites without immediately filling his 2 MB hard drive, so with that out of the way he starts on building the radio.

In the 90s, wire wrapping was common for prototyping so he builds a hardware digitizer interface using this method, which will be used to help the computer interface with the radio. [Old Computers Sucked] is rolling his own hardware here as well, based on a Motorola MC3362 VHF FM chip and a phase-locked loop (PLL), although this time on a PCB since RF doesn’t behave nicely with wire wrap. The PCB design is also done with software from the 90s, in this case Protel which is known today as Altium Designer.

In the end, [Old Computers Sucked] was able to receive portions of imagery from weather satellites still using the analog FM signals from days of yore, but there are a few problems with his build that are keeping him from seeing perfectly clear imagery. He’s not exactly sure what’s wrong but he suspects its with the hardware digitizer as it was behaving erratically earlier in the build. We admire his dedication to the time period, though, down to almost every detail of the build. It reminds us of [saveitforparts]’s effort to get an 80s satellite internet experience a little while back.

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How’s The Weather? (Satellite Edition)

August 22, 2025 by Al Williams 2 Comments

When [Tom Nardi] reported on NOAA’s statement that many of its polar birds were no longer recommended for use, he mentioned that when the satellites do give up, there are other options if you want to pull up your own satellite weather imagery. [Jacopo] explains those other options in great detail.

For example, the Russian Meteor-M satellites are available with almost the same hardware and software stack, although [Jacopo] mentions you might need an extra filter since it is a little less tolerant of interference than the NOAA bird. On the plus side, Meteor-M is stronger than the NOAA satellite on 1.7 GHz, and you can even use a handheld antenna to pick it up. There are new, improved satellites of this series on their way, too.

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Bad To The Bluetooth: You Shouldn’t Use This Jammer

August 21, 2025 by Jenny List 12 Comments

Back in the day, an FM bug was a handy way to make someone’s annoying radio go away, particularly if it could be induced to feedback. But these days you’re far more likely to hear somebody’s Bluetooth device blasting than you are an unruly FM radio.

To combat this aural menace, [Tixlegeek] is here with a jammer for the 2.4 GHz spectrum to make annoying Bluetooth devices go silent. While it’s not entirely effective, it’s still of interest for its unashamed jankiness. Besides, you really shouldn’t be using one of these anyway, so it doesn’t really matter how well it works.

Raiding the AliExpress 2.4 GHz parts bin, there’s a set of NRF24L01+ modules that jump around all over the band, a couple of extremely sketchy-looking power amplifiers, and a pair of Yagi antennas. It’s not even remotely legal, and we particularly like the sentence “After running the numbers, I realized it would be cheaper and far more effective to just throw a rock at [the Bluetooth speaker]“. If there’s a lesson here, perhaps it is that effective jamming comes in disrupting the information flow rather than drowning it out.

This project may be illegal, but unlike some others we think it (probably) won’t kill you.

A diagram with one Tag and two Base Stations.

Using Ultra-Wideband For 3D Location And Tracking

August 19, 2025 by John Elliot V 15 Comments

Interested in playing with ultra-wideband (UWB)? [Jaryd] recently put together a fairly comprehensive getting started guide featuring the AI Thinker BU03 that looks like a great place to start. These modules can be used to determine distance between two of them to an accuracy in the order of 10 centimeters, and they can do so in any orientation and with obstacles in the line of sight. It is possible to create a network of these UWB modules to get multiple distance measurements at once and enable real-time 3D tracking for your project.

[Jaryd] gathers up nine UWB modules and uses a Raspberry Pi Pico for command and control purposes. He explains how to nominate the “tag” (the device being tracked) and the “base stations” (which help in locating the tag). He reports having success at distances of up to about 10 meters and in favorable circumstances all the way up to as much as 30 meters.

If you don’t know anything about UWB and would like a primer on the technology be sure to check out What Is Ultra Wideband?

2025 One Hertz Challenge: Blinking An LED With The Aid Of Radio Time

August 14, 2025 by Lewin Day 3 Comments

If you want to blink an LED once every second, you could use just about any old timer circuit to create a 1 Hz signal. Or, you could go the complicated route like [Anthony Vincz] and grab 1 Hz off a radio clock instead.

The build is an entry for the 2025 One Hertz Challenge, with [Anthony] pushing himself to whip up a simple entry on a single Sunday morning. He started by grabbing a NE567 tone decoder IC, which uses a phase-locked loop to trigger an output when detecting a tone of a given frequency. [Anthony] had used this chip hooked up to an Arduino to act as a Morse decoder, which picked up sound from an electret mic and decoded it into readable output.

However, he realized he could repurpose the NE567 to blink in response to output from radio time stations like the 60 KHz British and 77.5 KHz German broadcasts. He thus grabbed a software-defined radio, tuned it into one of the time stations, and adjusted the signal to effectively sound a regular 800 Hz tone coming out of his computer’s speakers that cycled once every second. He then tweaked the NE567 so it would trigger off this repetitive tone every second, flashing an LED.

Is it the easiest way to flash an LED? No. It’s complicated, but it’s also creative. They say a one hertz signal is always in the last place you look.

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A photo of the circuit board with components soldered on

A Solar-Only, Battery-Free Device That Harvests Energy From A BPW34 Photodiode

August 10, 2025 by John Elliot V 21 Comments

Normally when you think solar projects, you think of big photovoltaic cells. But a photodiode is just an inefficient, and usually much smaller, PV cell. Since [Pocket Concepts]’s Solar_nRF has such a low power budget, it can get away with using BPW34 photodiodes in place of batteries. (Video, embedded below.)

The BPW34 silicon PIN photodiode feeds a small voltage into a BQ25504 ultra-low-power boost converter energy harvester which stores power in a capacitor. When the capacitor is fully charged the battery-good pin is toggled which drives a MOSFET that powers everything downstream.

When it’s powered on, the Nordic nRF initializes, reads the current temperature from an attached I2C thermometer, and then sends out a Bluetooth Low Energy (BLE) advertising packet containing the temperature data. When the capacitor runs out of energy, the battery-good pin is turned off and downstream electronics become unpowered and the cycle begins again.

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Whispers From The Void, Transcribed With AI

August 8, 2025 by Heidi Ulrich 14 Comments

‘Hearing voices’ doesn’t have to be worrisome, for instance when software-defined radio (SDR) happens to be your hobby. It can take quite some of your time and attention to pull voices from the ether and decode them. Therefore, [theckid] came up with a nifty solution: RadioTranscriptor. It’s a homebrew Python script that captures SDR audio and transcribes it using OpenAI’s Whisper model, running on your GPU if available. It’s lean and geeky, and helps you hear ‘the voice in the noise’ without actively listening to it yourself.

This tool goes beyond the basic listening and recording. RadioTranscriptor combines SDR, voice activity detection (VAD), and deep learning. It resamples 48kHz audio to 16kHz in real time. It keeps a rolling buffer, and only transcribes actual voice detected from the air. It continuously writes to a daily log, so you can comb through yesterday’s signal hauntings while new findings are being logged. It offers GPU support with CUDA, with fallback to CPU.

It sure has its quirks, too: ghost logs, duplicate words – but it’s dead useful and hackable to your liking. Want to change the model, tweak the threshold, add speaker detection: the code is here to fork and extend. And why not go the extra mile, and turn it into art?