Crystal radio built from modern junk

crystal radio

[h. p. friedrichs] (AC7ZL) has some great plans for building a crystal radio. The stator coil and output coil are wrapped around the outside of a CDR sleeve. The tuning capacitor is constructed by sandwich two clear CDs between metal and attaching this inside the top of the sleeve. The rotor shaft is mounted using the bushings from a pair of disassembled potentiometers. A hot needle is used to tap the stator coil through the housing every fifth turn. Even though the parts aren’t very traditional it looks like a really solid radio. He’s got instructions for building a matching ear piece out of tea tins too.

18 thoughts on “Crystal radio built from modern junk

  1. This is a beautiful xtal set, his use of common items is impressive. Using a rotating coil helps out quite a bit when your trying to tune in a station. The tin box speaker desgin is very clever as well.

  2. A crystal radio is one of those “must-have-must-make” projects that most tinkerers at some point tackle, whether it be as a kid from a kit or like this. This one takes it to a new level…very very nice!

  3. But does it work?
    I’ve never seen a crystal radio that manages to convert the microwatts it pulls from the air into audible sound.

  4. to theblunderbuss:
    …i mention on my website that i have tuned the radio described to a strong local station and and collected enough energy from a fairly short antenna to actually light a red led. alternately, when used with headphones, the volume can be loud enough to make programming audible with the phones simply lying on the table. this is not stereo-level volume, to be sure, but a surprising loudness just the same.
    hpf

  5. Also check out Harry Lythall’s coffee-can-cavity-resonator “crystal set”. Works from a few hundred MHz up to 1GHz, try that with a traditional tank circuit!

  6. brasky:

    from the bottom of the article:

    This article was originally prepared for, and appeared in, the newsletter of the Xtal Set Society. Check them out!

  7. Wow great work!!

    Just would like to add that crystal radio is one of those “must-have-must-make” projects that most tinkerers at some point tackle, whether it be as a kid from a kit or like this.

    :)

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