Many thanks to SWLing Post contributor, Paul Evans, who shares the following video and article via Hackaday:
There’s been a spate of apocalypse related articles over the last few weeks, but when I saw an AM radio made from a hand-wound coil and an oxidized British penny, I couldn’t help but be impressed. We’ve covered foxhole radios, stereotypical radios that are cobbled together from found parts during wartime.
This example uses a variable capacitor for tuning, but that’s technically optional. All that’s really needed is a coil and something to work as a diode. Surprisingly, copper oxide is a semiconductor, and the surface oxidation on a penny is enough to form a rudimentary diode.[…]
Thanks for sharing this, Paul. I absolutely love simple receivers like this one. In the past, I’ve built several crystal radios and had great success hearing local AM broadcasters. Indeed, the very first kit I ever built was a crystal radio, then later a foxhole style receiver.
Post readers: Have you ever built a radio similar to this one that uses an oxidized penny? Please comment!
Click here to read posts from our archives that focus on crystal radios.
That The Clash’s London Calling happened to be on the first station he tuned up makes this all the better. Hardware hacking at its finest.
Oh how this brings back memories!
My late father was a ham radio operator. One of the gizmos I inherited was a pillow crystal radio. It used
– the internal receiver part of a 1960s style landline telephone,
– a diode soldered unto the receiver,
– an insulated long wire soldered to the receiver,
– long wire terminated to an alligator clip which was attached to a nearby metal window frame.
We had a 50kW am radio station a few miles away which was picked up very easily.
This DIY unit made late night listening before falling asleep possible back in the day when earphone transistor radios were just around the corner.
Those were the days!
The comments on hack-a-days are quite hylarous 🙂 … serously, that remembers radios mafe from shawing blades … but then you’ll still nerd some enough powerful xmtr to work