An ESP32-S3 is now keeping vintage tube radios alive as AM broadcast bands shut down across Europe. Builder GarethDaviesLondon published a small AM transmitter on GitHub that pulls an online radio stream and radiates it at 200kHz, targeting the European long wave band, via a pulse chain on a single GPIO pin.
The antenna is the real engineering decision here: a 3D-printed box with standoffs holds a widely spaced wire coil, generating just enough field strength for nearby vintage receivers to lock onto. No amplifier, no discrete RF stage. GarethDaviesLondon acknowledges the legality is questionable, but at this power level the signal barely leaves the room.
The project raises a harder question the article only hints at: could the same GPIO pulse technique scale to medium wave frequencies, which carry far more legacy hardware? Read the full write-up and the GitHub repo for the signal generation code, the coil geometry, and the streaming pipeline details.
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