# Potato radio **URL:** \ **Category:** Factual Questions\ **Created:** [January 24, 2014, 8:24pm UTC](https://boards.straightdope.com/t/potato-radio/679644 "2014-01-24T20:24:41Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Marcos75](https://avatars.discourse-cdn.com/v4/letter/m/f14d63/32.png) [@Marcos75](https://boards.straightdope.com/u/Marcos75)\ **Post date:** [January 24, 2014, 8:24pm UTC](https://boards.straightdope.com/t/potato-radio/679644/1 "2014-01-24T20:24:41Z")
As a young student in France, I remember a story told me by a cafe garçon about his dad being a POW in Germany during World War II and managing to make a working radio out of a potato and razor blades. While it seems impossible and it was met with scoffs of derision, Hogan’s heroes demonstrated that everyday household items could and were used as “fifth column” implements against the nazi tyranny. Antics aside, is there any remote possibility that a potato radio did indeed exist? ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [January 24, 2014, 8:35pm UTC](https://boards.straightdope.com/t/potato-radio/679644/2 "2014-01-24T20:35:09Z")
Probably a [foxhole radio](http://en.wikipedia.org/wiki/Foxhole_radio). ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [January 24, 2014, 8:36pm UTC](https://boards.straightdope.com/t/potato-radio/679644/3 "2014-01-24T20:36:54Z")
[Here you go…](http://en.wikipedia.org/wiki/File:Homemade_radio_receiver_with_razorblade.JPG) Not quite as simple as just a razor blade and potato, but close. The potato provided power (as we know from the scientific documentary Portal 2). The razor blade acted as a diode. And I imagine they had other scraps of copper wire and stuff as well, but it makes a better story if you just say “potato and razor blade”. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [January 24, 2014, 9:27pm UTC](https://boards.straightdope.com/t/potato-radio/679644/4 "2014-01-24T21:27:59Z")
the razor blade was part of the detector. a radio could work without any power other than that of the radio signal. only strong signals used with skill and a good antenna could be heard. a potato might act as part of a battery. with skill and the right parts and circuits this could provide some amplification. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [January 24, 2014, 10:08pm UTC](https://boards.straightdope.com/t/potato-radio/679644/5 "2014-01-24T22:08:15Z")
I have no idea what the potato is for. A classic crystal radio could be made with two razor blades (or one broken in two) and a pencil lead. The blades were stuck in something, edge up and parallel. The pencil lead spanned the blades. By adjusting the position of the lead, you could “tune in” different frequencies. While a potato could be used to hold the blades, its conductivity would be a problem. The hardest part of making a radio in a situation like a POW camp is the earpiece. Everything else is trivial to obtain. Making your own earpiece is a big hassle. Lots of fine wire, a small strong magnet, etc. Easier to barter with the goons or steal one. You only got amplification in those days using vacuum tubes. And a potato isn’t going to cut it power-wise. (And forget using a hundred potatoes. In parallel isn’t going to give you the voltage needed. In series and they’ll start cooking by the time you start producing enough power.) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 25, 2014, 1:44am UTC](https://boards.straightdope.com/t/potato-radio/679644/6 "2014-01-25T01:44:16Z")
It should be noted that a potato isn’t even the important part of a potato battery. The important part is having two different metals for the terminals. Once you’ve got that, you can stick them in almost anything. ---
**Author:** ![JWT\_Kottekoe](https://avatars.discourse-cdn.com/v4/letter/j/3ec8ea/32.png) [@JWT\_Kottekoe](https://boards.straightdope.com/u/JWT_Kottekoe)\ **Post date:** [January 25, 2014, 2:54am UTC](https://boards.straightdope.com/t/potato-radio/679644/8 "2014-01-25T02:54:16Z")
When I was a kid I tried to make a radio receiver using a razor blade and pencil lead as the detector. Fancy versions included a coil and variable capacitor. I never got it to work. Ultimately, I found a little glass encapsulated diode in a junk box and it worked fine with just an antenna, the diode, and an ear phone. ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [January 25, 2014, 3:21am UTC](https://boards.straightdope.com/t/potato-radio/679644/9 "2014-01-25T03:21:59Z")
Are we talking about electric potatoes? ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [January 25, 2014, 4:10am UTC](https://boards.straightdope.com/t/potato-radio/679644/10 "2014-01-25T04:10:16Z")
> [@tramp\_oh-leen](#): > > Interesting MacGyver comes to mind. Or the Professor from “Gilligan’s Island”. RIP. ---
**Author:** ![Marcos75](https://avatars.discourse-cdn.com/v4/letter/m/f14d63/32.png) [@Marcos75](https://boards.straightdope.com/u/Marcos75)\ **Post date:** [January 25, 2014, 4:09pm UTC](https://boards.straightdope.com/t/potato-radio/679644/11 "2014-01-25T16:09:54Z")
Thank you all for the responses. I guess the guy’s dad wasn’t very specific or the guy didn’t understand the mechanism.