Did Anyone Else Build A Crystal Radio As A Kid?

[Grainger49]

I was looking at today's Woot.  They have the current day version of the electronics kit I had as a kid.  I built a crystal radio and my dad hooked up a random length wire antenna outside.  It picked up stations way off like Chicago (from Atlanta).  I was amazed.

 

[mcandmar]

No, but i always wanted to build one and get some hands on experience with radios.

I have a GECoPHONE No.1 crystal radio which always fascinated me as a kid, but i've never seen it working.

 

[Natural Sound]

I built several of them. My dad worked for the phone company and had access to all kinds of electronic goodies. So I didn't exactly build a kit. I scavenged all the bits together along with an oatmeal container for the coil and rigged my own. That, a cold water pipe for ground and a hunk of wire out the window.

 

[caffeinator]

I built one from a kit that I think was from Radio Shack, along with a few other kits.  Later, I got the "65 in1" electronics lab sort of thing - it was about the size of a monopoly board, and had various components (resistor, CdS photocell, capacitor, buzzer, speaker, etc.) arranged on it, and each had these little spring terminals.  Following instructions in the book, one would connect components into a circuit using the supplied lengths of hook-up wire.  I loved it.

I wanted the "200 in 1" kit for another Christmas, but I got the computer kit instead...not one from which one would build a computer, but, rather, a sort of a rudimentary computer that used multiposition slide switches, connected with hook up wire, to execute 'programs.'  With an hour or so of hookup and the slide of a few switches, one could calculate precisely how likely they were to die alone, living in their parents' basement.

 

[Doc B]

I wanted the "200 in 1" kit for another Christmas, but I got the computer kit instead...not one from which one would build a computer, but, rather, a sort of a rudimentary computer that used multiposition slide switches, connected with hook up wire, to execute 'programs.'  With an hour or so of hookup and the slide of a few switches, one could calculate precisely how likely they were to die alone, living in their parents' basement.

Post of the month!

 

[Grainger49]

I think mine was like 12 in 1.  I built the radio and a couple of other things.

Oh, man!  I had forgotten the ground clip.  We ran a wire out the window and to a rod in the ground.  I guess my dad had sunk a copper rod for this. 

One Christmas my brother and I got rocket radios.  What a great toy!

I agree with Dan.

 

[Paul Joppa]

Yeah, I did the galena crystal/cat's whisker radio thing. Later I got a rocket radio - great for listening as a kid after I was supposed to be asleep! Eventually built a super-regen using a 1T4 battery tube, for short-wave listening.

After that I inherited a non-working Heathkit FM tuner (which I fixed by re-soldering a bad connection). We were living in a furnished house in New Jersey for a couple years, and there was a classic speaker - huge box, probably 12 cubic feet, with a multiway 15" drver - so I built my first "power" amp. Used one germanium transistor (SE obviously) and IIRC four D cells. The speaker was behind the curved bar in the living room ... late fifties/early sixties, cocktails were a big thing back then. I think I got around 20 hours from a set of batteries.

 

[Natural Sound]

My dad, a World War II veteran told me about making a radio out of a razor blade. It was something like this.
http://bizarrelabs.com/foxhole.htm

 

[Tubejack]

I got the bug about 1960at age 11, wanted to build a 1 tube AM transmitter I think I saw in "Boys Life", or "Popular Mechanics", but we didn't know how to secure all the parts needed.  A friend of my father's recommended this:  http://www.mequonsteve.com/knight-kit/1962-440-441.jpg.  Spent many a day in the basement with it.  This lead to a Knight-Kit Space Spanner and then a Star Roamer, and my first "real" stereo amp kit, the KG320 and KG-50 FM Stereo Tuner kits.  Still have the amp. 

 

[Dnorris]

Each student in my 7th grade shop class built a cat whisker crystal radio, then we moved on to building a simple electric motor. That would have been 1965 or 66. Back when we actually learned useful information and skills in "shop class". Also learned about charging a capacitor and tossing it to an unsuspecting classmate, too! Probably would get expelled and sued for that today.

 

[Grainger49]

Thanks to all for the chuckles and nostalgia.

 

[2wo]

I built one of the razor blade ones. with enough jiggling of the pencil point, I was able to get it to work for seconds at a time...John 

 

[Grainger49]

I have heard about the razor blade.  I don't remember that being part of my kit.  How did that work?

 

[Doc B]

The razor blade version is known as a foxhole radio. It wasn't a kit (well it was in a shaving kit, I guess), it was a field expedient receiver invented by resourceful soldiers.

 

[cpaul]

I built one or two, and have also built one with my now 12yo son.  Soon will with my daughter if she'll put up with me.  But more interesting to me is a radio my dad built as a kid, roughly mid to late 1930s I think.  Complete with the old bakelite aviator style headphones.  Someday I want to fire that up again.

 

[Grainger49]

Oh, that would be cool.  Listening to the radio your father listened to 80 years ago.

 

[Natural Sound]

I have heard about the razor blade.  I don't remember that being part of my kit.  How did that work?

The razor and the oxide on the surface of the metal along with a pencil lead acted as a point-contact diode. This crude diode acted as an RF detector. The old blue "safety razor" replacement blades from yesteryear are said to work the best. It is believed that the bluing process applied a coating of selenium dioxide to the metal.

 

[Grainger49]

Ok, thanks!  I got it now.