Crystal Radio History

In the early 60's I was in a radio/tv class at vocational HS. one off our test was to make L/C circuit so i picked 27 mhz. after i passed the test i added a 1n34 and variable capacitor and had a CB crystal radio with the output connected to a tape recorder it worked very well KG4NZW 73

 

Again going back in time, does anyone remember those little "Rocket Radios"?

 

Yep... I had one.... The tuning rod tip had a red plastic ball ...

JB

 

Yep, remember the little rocket radio, I believe mine was grey in color ! BG

 

It is interesting to see just how many people came into radio as a result of buildings crystal set. With the steady demise of AM broadcasting in many countries this way in may not exist for much longer. I also had a crystal set as my first introduction - later added a transistor to amplify the very low signal levels! It was all great fun.

 

My first radio involved magnet wire wrapped around an oatmeal box. Pop donated a germanium diode, a Hammarlund variable capacitor, and some military surplus high-impedance headphones to make it better. I didn't do much listening on it, as we had a Hammarlund receiver for that. What hooked me was the "making it better" part. I still have that Hammarlund variable capacitor. It is part of my magnetic loop today.

 

My brother and I both had one. I could hear KSL in Salt Lake City from our bedroom in SillyCone valley with one of those!

 

On the same antenna I DX'ed with my 100mW cb HT, a couple of scrapped transistor radio IF transformers were used to make a crystal radio color organ. The transformer's output was enough to fire 2 neon lights. One through a small cap for the bass. My electronic shop teacher says: "no way". Mr. Muhrhead, how could you doubt me? Must of been one heck of an antenna. 40 awg, crisscrossing a 70 foot backyard and up to my 2nd story window. Stepmom would take it down with her broom stick & I'd have it up that evening after school again & again. It was my escape electronics, and still is more than ever I'm saying. Do the paper towel tube dual coil design. SW on 49 meters no problem.

 

Here in the UK, Sinclair sold a kit to make what was at the time, probably one of the smallest radios in the world.

It was just a simple crystal set, with an ordinary crystal earpiece . . . but it worked amazingly well, even with just a the few feet of wire supplied as an aerial. (As a 10 year old lad I bought one and built it)

He later added a couple of transistors to make a TRF miniature radio, with regen and a small ferrite rod that was amazingly sensitive - pictured here:



Roger G3YRO

 

Yes, same here, a 1N34 germanium diode, and a 2N107 audio amplifier.

 

Is that the same Sinclair of the famous Timex/Sinclair computer?

 

My first xtal radio was a Philmore, bought in Schnectady, ny. early 1950's . Since then I have found out that most any piece of metal
from my hardware box will work with a cats whisker. Plated fender washers work great. 73

W1HRM

 

My Dad bought me one. It was magic to hear KDKA out of that silvery rock!

 

I remember back in the days where aircraft receiver crystal radio pens were commonly sold. No batteries required, looks like a pen with a wire dangling from it, you probably can't hear ATC or the tower but can hear the pilot. Occasionally I look ebay to find one of these, none so far. One seller had some crystal radios, intention be able to listen to aircraft comms without a unit with local oscillator. Problem is the way it was packaged it looks like a remote detonator.

Speaking of crystal radios, the program on History Channel with R. Lee Ermey on various military aspects had quizzes where he presents a problem "build a radio receiver using only common items such as these." (a small collection of objects). Following week Ermey described from these items a crystal radio can be built. He also showed three assembled and working crystal radio sets that viewers built and mailed to the producer of the show. One set was a very nice and neat construction of the coil and wood frame. Ermey commented, "this came from a Tech Sergeant in the Air Force that has too much time to spare!"