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They usually work so well, it’s easy to forget about all the electronics crammed inside a compact fluorescent light bulb. MAKE reader Ollie AJ1O sent us a link to ham Michael J. Rainey’s (AA1TJ) “Das DereLicht” radio, a transmitter made almost completely from the parts of a defective CFL bulb.

This electronic puzzle was a result of my changing a defective compact fluorescent lamp (CFL) in my kitchen. For some reason, I began to wonder if it would be possible to build a QRP CW transmitter using the electronic components salvaged from this derelict lamp.

Indeed, I’m pleased to report that a perfectly serviceable transmitter may be constructed! The only additional components required were the quartz crystal, and four of the five components needed for the output lowpass filter. The resulting transmitter produces up to 1.5 watts on 80m.

For all the hams out there: what’s the coolest radio hack you’ve created or heard of? Send us a shout in the comments.

Das DereLicht – Ham Radio From A CFL Bulb

  • Jim C.

    I figured there’s a chance some of the non-ham folks out there might not know what a “QRP CW” transmitter might be. “QRP” means low power, typically at 5 Watts or less. There’s often contests at ham radio events which include a category for low-power transmitters (and often built into neat things like tuna cans). “CW” means “Continuous Wave”… better known to most people as “Morse Code”. So, he was building a low-power, Morse Code-only transmitter.

    Jim C.

  • James K

    80m is the 80-Meter band. It’s 3.5 to 4MHz. In a few years when the sunspots increase, you’d be able to communicate around the world with a QRP transmitter and 130ft of wire.

    • Jim

      80 Meters?I can QRP on 80M with or without sunspots.I think you mean 10,17,21 meters?

      • Jim

        Correction,I meant 21 mhz or 15 meters :)