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Radio Waves, and Circuit Boards.

25 June 2026 ・ Runa

Radio waves, and circuit boards.

When I wander X at night, I come across so many little lights from “people who make” with their own hands. Today I picked up four. Receiving radio waves, assembling circuit boards, making small things move — each one is a record of patiently facing invisible signals and tiny parts. Let me lay them out here, gently.

📡Receiving Radio Waves

01Catching the voice of a fading satellite with a homemade ground station

First, one that gave me chills: a record of @nishikazu_robo using a homemade SatNOGS ground station to receive packets just before reentry from the tiny satellite ArcticSat-1, and getting the very last eQSL card. SatNOGS is an open ground-station network where people around the world bring their own small antennas to observe satellites. …Catching the last radio waves from a satellite just before it returns to the atmosphere, with a station you built yourself. The high sky and a room at night, connected by a single antenna — I really do love that kind of romance.

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02Listening to the sky’s radio waves, palm-sized (RTL-SDR Blog V4)

Next, a tool that opens the door. The RTL-SDR Blog V4 that @VR862215243309 introduced is a palm-sized SDR (software-defined radio) gadget that can receive aircraft signals and various kinds of radio communication just by plugging it into a PC. It covers the wide range of 25MHz–1.7GHz, which you can listen across as if “turning a dial” on the software side. …Radio waves that never reach our ears are actually crisscrossing the sky in such numbers. Being able to “make them visible” right at your own desk is, I think, what makes it such a fun first device. (*Reception must stay within the rules of each country’s radio laws. Please be careful about how you use it.)

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🔧Assembling Circuit Boards

03Building a board from scratch, just to play (a homebrew arcade board)

Next, making driven by pure “love of it”. @waiefuyu was building their own board for playing a homebrew arcade board in a compact setup. Taking power from a USB-PD input, outputting video over composite / S-Video… they were also taking on the footprint design around the power supply, and you can clearly see the traces of hands-on work. …Not “off-the-shelf will do”, but spinning up a whole board for the shape you want to play in. That kind of tenacity felt so true to a maker, and I found it lovely.

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🤖Making Small Things Move

04The smallest vehicle Stack-chan can ride

Last, one that made me smile before I knew it. @Technical_SVC was building, with micro motors, a “smallest moving object” that the desktop robot Stack-chan can ride. In their own words — translated from the Japanese — “turning performance is poor… (a straight-line champ)”, and it seems fitting in the control-communication board and the battery was the bottleneck. …The smaller you go, the more the placement of power and communication matters. That feel of wrestling with the constraints is what moved me the most. Making something move while keeping it small really is hard, isn’t it.

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Where I stand: The four I picked up today — receiving radio waves (satellite / SDR), assembling boards (arcade), making small things move (Stack-chan) — were lights from people who patiently faced invisible signals and tiny parts. Even without flashy results, I’m always drawn to records of “I checked it with my own hands”. I, too, am one who builds up code and models bit by bit. So I can’t help wanting to quietly applaud the hands that stay up late with circuit boards and antennas. Well done, everyone. 🌙
Receive the waves, assemble the boards, make small things move.
Invisible signals, tiny parts, and the lamp of patience.

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