A Look At Two Crystal Radios

In this video I demonstrate two crystal radios I recently picked up, and give some history and technical information on what crystal radios are.

[@michaelkesti3917]

I received the radio that appears at 00:31 for Christmas when I was 7-years old. My dad helped me build it and we set up a ground and a long wire antenna complete with lightning arrestor. I listened to a hocky game that was going on about three blocks away and don't recall using it again but it was the beginning of my electrical engineering carreer.

[@Sylvan_dB]

The board looks like oak to me. :) I had several crystal radios as a kid. We even built them in cub scouts one year. I had one "modern" plastic-cased crystal radio (black base, green transparent cover) that used a metal slider on the coil for tuning (most, like your plastic one shown, used a variable capacitor). I remember it working really well, until it helped us discover our house had a significant voltage and amperage potential between a heat register and an outlet screw. My father had helped me "ground" the radio to the outlet screw. I had extended a wire thru a lot of the house up near the ceiling for an antenna. My younger sister knocked down the antenna wire tossing a ball one day while I was at school. The antenna contacted a heat register in the floor, heated up and burned its path into the carpet wherever it touched. The plastic coil form in the radio melted into a pile of slag. The diode burnt up, turning the glass case into a mirror and cracking in half. My sister's ball came to rest against the antenna wire which melted into the side of the ball. Luckily my mother was paying attention and there was no further damage. It turns out the furnace ductwork was a better ground than the outlet. After I came home from school and cleaned up the mess as best as I could, I experimented and found I could cause a light bulb (incandescent probably 60w or 100w) to glow dimly by connecting it between the grounded heat register and the suspect outlet screw. The wiring in most of the house was two conductor in a fiber jacketed cable - no ground. The furnace in the basement was newer and grounded. I replaced the outlet and at least that cover screw was no longer live! A few years later I was testing miniature christmas lights and left them plugged in too long and melted a pattern of the lights into the carpet. It's a wonder I survived childhood.

[@barryf5479]

I recall receiving the same Remco crystal radio as a gift for Christmas sometime in the 60's. I recall it had a plated metallic ball that was used to rub along the coil windings which had to be lightly sanded to remove the insulating enamel. The round, plastic "antenna" was nonfunctional as you know. I still have the tuning coil and over my youth, I used that coil to construct another breatboard type of crystal radio. I recall going to a TV store to get a germanium diode (1N82, I believe) manufactured by International Rectifier. It's white with red printing on it. I recall my mother taking me to a TV repair store to get that diode. Interesting is I eventually got a job in high school working for that same shop for the same person I bought the diode from. I still have the radio parts and it's functional although I changed the design a little. Like you, this radio was instrumental in my developing interest in electronics. Also like you, I ended up with an EE degree and a successful career. I remember stringing wire all over our front yard to try to make a "good" antenna as well as experimenting with grounding stakes in the front lawn. Remco science kits were simple yet interesting. Thanks for the memories.

[@acestudioscouk-Ace-G0ACE]

Thanks for the video, it was a nice walk down memory lane. It's a shame that AM stations are dying out but there seems to be a growing number of crystal set builder groups on Facebook.

[@davidclarke6658]

I had the same radio shack unit in the early 80s as a kid. It worked fine.

[@kensmith5694]

It really is a shame that AM radio and radio in general is going away. I put this down mostly to bad programming by the owners of stations and to a lesser degree to the other options we have for entertainment. Having a local station that gives local traffic, weather, news and things like that is still very useful even in these days of navigation apps on our phones. A local radio station can tell you that there is about to be big trouble somewhere long before the traffic piles up. I built quite a few crystal radios in the past. One of my more complicated ones with a tuned antenna could drive a speaker well enough that you could sit near it in a quiet room and comfortably listen to the radio. Back then there were about 10 stations.

[@alexinnewwest1860]

Thanks for this :-) Looks like the wood is Oak

[@guidoclaerhout6620]

Don't forget that specialists are watching!

[@user-qc6is4cv1z]

Ok