Anyone built a crystal radio kit?
 

I'm looking for a recommendation on a crystal radio kit that laypersons could build. Our local community radio station asked me if I'd be interested in leading a sort of workshop, to get people interested in radio and have a little fun building a crystal radio. I said that might be fun and I would look around for a good quality kit. Any suggestions?

not exactly a crystal radio kit, but I had one of these when I was kid. Looks just like the one from Radio Shack back in 79'
http://www.ramseyelectronics.com/cgi...action&key=AM2

Here's another possibility, see the first item
http://www.oselectronics.com/ose_p144.htm

I'm pretty sure you can make one with a coil of wire, germanium diode as the crystal and one of those little earphones. I think those are crystal headphones too. Your typical set of stereo head phones have too low of impedance to work.

I had one of those from radio shack too. Looks the same except for the artwork.

The Xtal Set Society sells a range of crystal kits:

http://www.midnightscience.com/kits.html

You can also buy a basic kit from Antique Electronic Supply:

http://www.tubesandmore.com/

If this will be a group project, you might consider building a kit yourself beforehand, and trying it out in the location where your group will be working. It might be disappointing if everyone completes their project and you hear a chorus of "Can you hear anything?" "I can't hear anything!" :)

Phil Nelson

I'll echo the test it first suggestion.

And, keep in mind that a crystal set needs a pretty good antenna and a good earth ground to function properly.

You don't really need a kit to build a crystal radio :-)
All you need is a BC tuning air-variable cap, maybe a trimmer, a germanium diode, a crystal headset or earphone, and some wire (actually, a lot of wire, unless you live very close to a transmitter)!

www.tubesandmore.com has everything you need.

There are also plans and designs for more and less sophisticated crystal radios (even FM!) on the web and in a variety of books (see the link above).

Maybe building a superregenerative receiver would be a little more interesting and give you a little more reception capability... :-)

EDIT: oops, except for the last sentence, you already got all of the above from earlier posts! Sorry :-P

Sure, about 64 years ago.

Here is a good resource for crystal radios. He has a nice collection of old crystal sets, parts, plans for building, etc.

http://oldheadphones.com/crystal/index.html

Thanks for the links. This will be un-scientific types each building their own, many of them artsy types. If I was doing this myself I would use what I have - actually made a razor blade foxhole radio from junk once - but it's probably not a good idea to send THESE people off with a shopping list for air-variables and miles of wire to wind their own coils. A simple kit everyone can buy may be the way to go. I'll look around though. Maybe we buy the coils, get the headphones and diodes in bulk...

I've got one I built not long ago ad anotherI bought not long ago but have not built. I'll dig them out and get the information as to manufacture. Each was something like $10. Big decision for a kit is whether the maker should wind the coil or it should be prewound as it is the most difficult part of the project.

I built the oatbox radio a few years ago. It was pretty easy and didn't take much time other than ordering the parts.

Or wht about a foxhole radio? Only parts you'd need to acquire would be wire, an old lead pencil and some razor blades and a crystal or magnetic earphone. A little scrap of wood, an old tissue roll and you areset to go.

http://bizarrelabs.com/foxhole.htm
http://en.wikipedia.org/wiki/Foxhole_radio

Good reading.

The Foxhole radio is actully a product frm WWI. If anyone has a set of The Book Of Knowledge from the '30s, the history and construction details are in an article. I thik the set I had as kid was 1935. In the article it was called a foxhole radio and also the trench radio. I suspect the thought that it originated during WWII is from the name foxhole that is associated with the foot soldiers digging in.

I built one of these recently. I wound my own coil, found a blue razor blade and along with the safety pin/pencil lead I just used metal push pins to hold everything to the board and make the connections. I used a large paper clip as a fine tuner. It works very well and was a fun project. Most people have never heard of these things and everyone was amazed that you can get stations on something so "Mcguyvered". I agree that the ground and antenna wires are crucial to making these or any crystal radios work. I bought one of those Smithsonian kits at the toy store. It's a breeze and works great once you get the wires hooked up. I've built a couple crystals from scratch and they are pretty easy to do. The best one I've found is not a kit, it's the "Crystal Rocket Radio" from Restoration Hardware. It's a replica of a radio from the 50's. The best thing about it is that it only has one wire that acts as both antenna and ground so you can use it just about anywhere you can find some grounded metal to clip it to. The major disadvantage with most simple crystal sets is that you are only going to get one or two stations, but they are more about fun than function.

I think something like this would be fun to build with my nephew.

I actually got interested in them again for a fantasy project. I've been into old tme radio shows for a couple of years and even went so far as to buy a Hallicrafters SW500 tube SW radio to listen to them on a local AM station that boradcasts Monday through Thursday nights. Went with the Hallicrafters so I could listen through a set of magnetic headphones. I'm plannng on building a low powered tube AM transmitter and broadcast the shows through it an pick them up on the crystal radio. Yes, I absolutey am looking to go back to my childhood and hear them as close to original as I can get and that's a long way from listening to them through my laptop.

I built one when I was a kid. It was fun and very gratifying to build something that actually worked!

Crystal radios
 

When I was a kid, I would tape record broadcasts from my crystal radio. The recordings were stellar, as they would be "crystal clear" (ie, free of any static or interference.) I was amazed by the sound of these taped recordings. Quite amazing.

I built one also as a kid. I remember it had a green clear plastic case. I corkscrewed all the wires by winding them around a pencil. It looked real nice.

I built a foxhole radio a couple years back and couldn't get it to work. Never did figure out why.

Did you use a blue razor blade? The foxhole radio is tricky. Mine worked great when I finished it, but now it doesn't seem to want to. I might try swapping out the razor blade and see if that won't get it going again. You can still find blued razor blades (the one I used is for cutting carpet), but you can also take a normal blade, scuff it up and let it rust a little. You can also heat the blade to blue it yourself.

Is it possible to build a crystal set out of a dead transistor radio? i mean, using a the tuning capacitor, a germanium diode, maybe one of the miniaturized ferrite core coils and so on?

Also, is a high impedance 1920s moving iron cone speaker suitable for a crystal radio?