… for Kids from 6 to 60


One of the most compact sets you’ve ever seen!

No Batteries.
No Electricity.
No Tubes.

It really works. You’ve seen it in comic strips – now it’s available for gift giving. Uses Radar Crystal Detector as developed by U. S. Air Forces. Receives regular AM radio broadcasts. Can be connected with wire for use as telephone system or as extra personal speaker for your home radio. Nothing to wear out or replace. Aerial and ground required,, for better reception.

$2.98 P.P.

Leotone Radio Corp., 65 Dey St., Dept. SM, New York, N. Y.

  1. Charlene says: December 14, 201011:23 am

    How did this work without power?

  2. Kosher Ham says: December 14, 201011:34 am

    It got the power directly from the radio waves (like a crystal set.) The crystal acts as the “tube” in this case– diode to be specific.

  3. Don says: December 14, 201012:13 pm

    The first “electronic” thing I ever built was a crystal radio, using a coil wrapped around an empty TP roll and a safety pin, a piece of pencil lead, and a rusty razor blade as the “crystal”. With the right headphones and a lot of tinkering it would pull in WLS from Chicago . . . at night, of course. I was in NW Minnesota . . . .

  4. JMyint says: December 14, 201012:24 pm

    I had built a crystal radio from a kit when I was a kid. It was a germanium diode, a variable coil, a disc capacitor, an earphone and ground wire with an alligator clip. It could pick up maybe a dozen AM stations. You tuned it by moving the slug in coil.

  5. Kosher Ham says: December 14, 20103:20 pm

    Re: the razor blade.

    It’s amazing what you can make diodes out off. I’ve heard of folks with braces in their teeth picking up radio stations with their braces!

    Germanium diodes were the so called “crystal diodes,” an actual crystal set would use a “cat whisker” and a galena crystal.

  6. GaryM says: December 14, 20103:24 pm

    Many years ago I had a phonograph turntable that would pick up a nearby FM station.

  7. MikeBurdoo says: December 14, 20105:18 pm

    I wonder how you could “connect it with wire for use as a telephone system”. Seems unlikely.

  8. John Savard says: December 15, 201012:29 am

    A loudspeaker also works as a microphone, since if you talk into it, the speaker coil is moved relative to the magnet, generating electricity. So you can connect two loudspeakers together to work as an intercom.

  9. carlm says: December 15, 20101:39 am

    The original crystal sets used a piece of Galena and a firm wire called a cat’s whisker. The adventure of the early radio days was to find a point on the crystal where it would act as a diode. The coil acted as a tuned tank circuit which selected the radio frequency. The diode rectified the RF signal and acted as a AM detector. What is left is the audio. There is enough energy in the transmitted signal to power a small earpiece. Later germanium crystals with a wire element were embedded in glass and worked as a low power diode. Diodes are still used as the detector in radios even today. The signal is now electronically amplified. In the early 1960’s I had a similar radio that was the size of a ball point pen. It worked quite well.

  10. Toronto says: December 17, 20102:44 pm

    What’s really odd is that Dick Tracy is one of the worst drawn strips of all time, yet the artist who penned this ad still managed to mangle Tracy’s iconic face. There’s sort of a Terry and the Pirates thing going on there, rather than a proper Fosdick jawline.

  11. blast says: December 19, 20105:22 pm

    A “Radar Crystal Detector,” huh?

    Has anyone ever compiled a list of “malarkical” adjectives added to products for no very good reason? The 20th century is full of them (not that there weren’t suckers before then).


  12. TomB says: December 20, 20108:35 am

    According to “A Radar History of World War II: Technical and Military Imperatives” By Louis Brown, Engineers returned to crystal detectors for radar as they performed better than vacuum tubes – lower transit times and no interelectrode capacitance.

    Instead of catwhiskers and galena, they began experimenting with silicon and germanium, fiddling with the impurities and encapsulating them to be robust.

    Therefore, I could argue that a 1N34 diode could be a “radar” crystal detector if it came out of this research. Inside a 1N34’s glass envelope is a point contact structure, just like a catwhisker.

    Putting the word “radar crystal detector” has more zip, zing, and zowie than “diode”. Who can blame them.

  13. slim says: December 20, 20103:21 pm

    In 1952, I believe the word diode would have referred to a vacuum tube. A radar crystal detector is a real thing. I was an ETR3 (radar tech) in the mid sixties, and worked with them. They were point contact and very sensitive.

  14. hwertz says: December 20, 20106:14 pm

    “Has anyone ever compiled a list of “malarkical” adjectives added to products for no very good reason?”
    Well, the one to throw on there now (for computer products) is “cloud computing”. Originally was hype, but vaguely referred to putting your work on a virtual machine or similar partition, and then being able to run as many copies of that as you need on a computing cluster. Now? Look at those Microsoft ads, they lost big time in providing anything resembling cloud computing products so they’re just sticking the word “cloud” on video streaming, reading E-mail, editing photos, even word processing.

  15. TomB says: December 20, 20108:50 pm

    I’ll submit “4G”. The telecoms are calling their LTE rollouts “4G” even though it doesn’t quite make the 1Gb/sec base station speed required by the standard.

  16. Chris Razor says: January 14, 20113:53 pm

    NW MN to Chicago on a razor detector!
    That’s the farthest I’ve ever heard of using a razorblade.

    Before your post I had only heard that local stations could be picked up with such a detector.
    For years that’s all I got, even with a 90 foot antenna and a good circuit.
    Then last year I received a couple stations 300 miles away and one almost 500 miles away in Canada.

    I later saw a post from a guy who heard a station 100 miles away.

    Do you know how far Chicago is from where you lived?

  17. Chris Razor says: January 14, 20113:55 pm

    I heard that in WWII the US soldiers could listen to the Japanese radios sending transmissions from their planes without being detected because the razor radios did not put out any RF like regenerative tube radio would.

  18. Firebrand38 says: January 14, 20115:06 pm

    When something starts with “I heard…” then you can usually count on it not being true.

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