PhD Crystal Radio Has Pizza Capacitor

Crystal radios are old news, but great fun. What would happen if a PhD designed a crystal set? By PhD we mean Pizza Hut Deliveryperson and [John Greenlee] (who may not actually be a PhD of either kind; we don’t know) gives us a good idea with his crystal radio in a pizza box.

Pizza boxes aren’t the only food-related material in this radio. [John] makes a tuning capacitor out of cake rounds. Coincidentally, he decorates the tuning capacitor to look like a pizza.

The schematic itself is unremarkable–just a common crystal set. But the construction of the chassis and the capacitor make it an interesting project. If you know a young person that has any interest in radio, a crystal receiver is a rite of passage you shouldn’t deny them and this one is certainly a novelty. The picture of a pizza takes it even one step further than this YouTube build, which is nonetheless a good resource.

The instructions are well done, although some of the parts may be slightly hard to find. Germanium diodes and high-Z earphones are not as plentiful as they used to be, although you can still find them if you look.

This pizza box rig could be a gateway drug to more serious crystal radios. Or you could go smaller and try building one in a match box.

35 thoughts on “PhD Crystal Radio Has Pizza Capacitor

  1. I wonder if pizza could be used as a mm-wavelength AR coating for astronomy – it would be a great improvement over the difficult materials-science problem we are currently working through in the lab I work in!

    1. Aw dammit, you beat me to it. +1 to Mano
      Where’s a good source for Germanium diodes? I have plenty because I keep older computer cards. They are usually the glass ones.

        1. Haha? You got me.
          I try not to walk into those. I would walk out with 2 carts full of stuff! Thanks. Found a military surplus place, better wait till I have room to desolder first.

          1. Was sarcasm. I’ve noticed that most of your posts have a certain lack of quality, and responded in a similar manner.
            Or was it? Dun dun dun.

  2. On a tech note I see it is a loop design, cool. My experience with crystal sets was always with the long wire and the necessary ground. The pizza box makes for large or xtra large loops. This can also be used as a passive tuned loop antenna coupled up next to the loop antenna built into virtually all radios except the easily lost little loop antenna that comes with microprocessor run stereos where they would pollute the otherwise builtin AM antenna. If the wires in the loop were air spaced 3-5mm it would have higher gain with the higher Q.

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