Crystal radio built from modern junk

posted Nov 16th 2005 11:00am by Eliot Phillips
filed under: wireless hacks

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.

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Comments [17]

Reader Comments

Right ON! I remember my first Radio shack crystal set. Hours of fun.

Posted at 11:30 am on Nov 16th, 2005 by hopp

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.

Posted at 11:40 am on Nov 16th, 2005 by John

“Clever” is indeed the word of the day here. I never would have thought to use a CD spindle for making a crystal radio!

Posted at 12:13 pm on Nov 16th, 2005 by furtim

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!

Posted at 1:58 pm on Nov 16th, 2005 by steve

Thought some people on this page might like this :-)

http://sfbayarea.craigslist.org/about/best/sfo/66795671.html

Posted at 2:00 pm on Nov 16th, 2005 by alex

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.

Posted at 3:31 pm on Nov 16th, 2005 by theblunderbuss

…then again, the ones I’ve seen weren’t as advanced and certainly did not have capacitors.
Stupid kits. grr.

Posted at 3:38 pm on Nov 16th, 2005 by theblunderbuss

whan the radio has a properly tuned tank circuit it need no power, other than amplification purposes if you need it loud

Posted at 5:16 pm on Nov 16th, 2005 by monster

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

Posted at 5:17 pm on Nov 16th, 2005 by h. p. friedrichs

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!

Posted at 5:35 pm on Nov 16th, 2005 by Wim L

I saw something very similar to this project, a crystal radio made from an empty cd spindle, in the March 2005 issue of The Xtal Radio Set Society. You can read the issue at http://www.midnightscience.com/comp.html

Posted at 6:13 pm on Nov 16th, 2005 by bill brasky

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!

Posted at 8:12 pm on Nov 16th, 2005 by mewse

That is nothing less than the art of radio right there.

just beautiful.

Posted at 7:39 am on Nov 17th, 2005 by strider_mt2k

I want one !!

Posted at 10:00 am on Nov 17th, 2005 by Fred

I want one !!

Posted at 10:00 am on Nov 17th, 2005 by Fred

NICE !! I must be quite the nerd, ’cause I’m actually excited about maybe building one of these myself..

Posted at 6:34 pm on Nov 17th, 2005 by Sum Dum Guy

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.

Posted at 1:22 am on Mar 20th, 2009 by Modern Metal Art