💾 Archived View for dioskouroi.xyz › thread › 29348950 captured on 2021-11-30 at 20:18:30. Gemini links have been rewritten to link to archived content
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So somewhat related, I cant find a half decent crystal radio kit on Amazon. Makes me really sad considering how dominant Amazon is.
I got one as a gift when I was maybe 7 years old. Making that radio with my mom, from essentially wires and the crystal and then hearing music through that little piezo ear piece might have been the most wondrous experiences of my life. Like, my family isn’t religious at all and as an adult I’ve come to identify as a materialist, but that… that was the closest thing I can think of to a religious experience. I assembled _wires_ such that they produced _sound_ sent _invisibly_ through the air _by other people_, and because of the way it is sent _it’s completely passive and requires no batteries_. Absolutely mind-blowing experience for me as kid.
Funny. I was fascinated in the same way by the crystal (germanium diode) radio kit I built as a kid but I wish now I'd built one of the "oatmeal box" more-or-less-from-scratch radios. It's probably easier than ever to do that - you can get galena off ebay.
to be fair there's not much on the air these days to pick up using a crystal anymore (around me at least)
but an SDR would let you teach much much more about whats going on in the invisible :)
https://www.hanselman.com/blog/software-defined-radio-is-a-g...
https://smile.amazon.com/NooElec-NESDR-Mini-Compatible-Packa...
Yeah the part about not requiring batteries was fascinating to me when I was little. My dad had located an old one from somewhere; I remember him showing it to me and having grown up with what were more modern radios at that point, the fact it could work without batteries was somehow at the same time mystifying but also made the world of electronics seem more approachable.
Reading about this leads me to wonder if there are certain benefits to many of these very old designs that have been lost due to overlooked priorities. As in, I'm not saying we should all be using crystal radios again but having a functional radio that doesn't require power seems like a plus at some level.
> Like, my family isn’t religious at all and as an adult I’ve come to identify as a materialist, but that… that was the closest thing I can think of to a religious experience.
I like to think of electromagnetism as a form of magic (in the supernatural/religious sense). In the days before radio, the idea of moving energy and information over pieces of metal or thin air would be considered sorcery or witchcraft. Today its so much more advanced with pocket computers literally putting the world at our fingertips. I can casually talk to people on the other side of the planet in near real time.
When I was a kid my crystal radio kit was beer powered!
https://archive.org/details/dicksmithsfunwayintoelectronicsv...
Dad bought me Dick Smith's electronic kits when I was 8 (it was an Australian thing). I didn't wind up going the EE route, but I will credit it with giving me the basics early in life so that whenever talk of capacitors and resistors came up I knew how to properly parse the information.
I remember that one. IIRC the instructions finished by telling you not to drink the beer afterwards.
Could one have invented radio in Ancient Greece or Rome?
I’m now deep into the early history of spark gap radio…
Yes. They were able to draw wire for jewellery. The could smelt iron so they could have made electromagnets, generators, electric motors, transformers, and loudspeakers. That's enough for spark gap transmitters and wired telegraph.
Hero of Alexandria made, or at least described, a simple steam turbine. But it was just seen as a toy or philosophical talking point and it wasn't until over a thousand years later that steam power became useful.
Half the challenge is knowing that something can be done and having some idea of what might be achieved. The rest is just work. :-)
See
https://en.wikipedia.org/wiki/Aeolipile
> Hero of Alexandria made, or at least described, a simple steam turbine. But it was just seen as a toy
It was in fact a toy [0]. It was basically a kettle mounted on a spindle with two spouts on opposite sides. When heated the steam escaped via the spouts and the whole thing rotated around the spindle. For many reasons it could not have done useful work:
* Very low pressure - with no valves to maintain a working pressure or pistons to drive a machine
* Not engineered to withstand useful pressure (simple copper welds)
* No way to reload water when in use
[0]
https://en.wikipedia.org/wiki/Aeolipile
They also appeared to be able to make batteries:
https://en.wikipedia.org/wiki/Baghdad_Battery
But as the article states, they're not convinced anymore that they were. Never mind?
Well, only with the technology of electricity as a prerequisite. Which was invented not far from Rome and recorded in Latin:
https://play.google.com/books/reader?id=Ha9gAAAAcAAJ&pg=GBS....
... in MDCCLXIX, or 1769 as we now represent it.
Neither the Roman nor Greek empires seem to have had many of the "practical tinkerer / gentleman scientist" social positions which were very important in the European age of discovery.
Radio was invented after we had Maxwell's equations - a theory that predicts electromagnetic waves. They probably could have built a radio, but they wouldn't have had the idea that one was possible without a couple hundred years of advancing math and physics.
But stoic philosophy was so focused on resonance (sympathy) in the universe. Somehow it doesn’t seem far from their worldview. It is kind of surprising that there wasn’t more tinkering and scientific development back then.
As for so many things in radio, or in the world generally, there are dedicated hobbyists. I am not a member, I just knew of their existence.