Crystal Radio Kit - your cellphone receiver's grandad
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- Опубликовано: 20 мар 2015
- repairs101.ca/crystal-radio-k...
Unboxing and assembling a forty year old Crystal Radio Kit made in USA (1975) to show the basic components of a radio tuner / receiver and explain how they work. FYI: models and science kits were an affordable gift for inquistive kids back before they all carried cellphones. #scienceproject #radio #cellphone
Transcript provided for the hearing impaired:
Alright today on Repairs101 I’m going to put together this forty year old Crystal Radio Kit because in spite of its stone-age technology there are still principles that we can learn that are applicable today.
Now you have to admit, it’s pretty amazing that after forty years all the parts are still in the box - and even more amazing than that is that after forty years the rubber bands are still stretchy.
OK now here’s the heart of the device. Well OK that’s just some sandpaper, but here inside this piece of corrugated cardboard is the crystal diode.
The tuner coil gets wound tight with the coils touching but not overlapping.
The length of the tuner coil is defined by the position of the tuner ball and where it contacts the coil. So, the further back it is, the longer the coil.
Now the earphone works because the diode filters out all the inverted sound waves caused by the AC transmitter at the radio signal’s source.
One end of the tuner coil is simply dead ended and the other is tied into the earphone wire and the ground circuit.
Use whatever you’ve got as an antenna - ideally it could be a piece of wire up to fifty feet long that’s insulated from the ground. I had best results from this twisted pair of ten gauge copper wires that I keep as test leads.
Now the ground circuit has to be just that - some metal circuit that connects to the ground. I’m thinking pipes or, you know, maybe a pipe or some kind of pipes.
OK so the last thing I need to do is take a bit of sandpaper and remove the insulation from an area on the tuner coil across which the tuner ball slides and makes contact.
So sliding the ball back and forth changes the length of the tuner circuit and tunes in different broadcast signals.
You’ll notice there’s no power source for this. It simply takes the energy from the radio waves that it samples with its antenna right out of the air. Amazing, isn’t it?
RADIO ANNOUNCER: “…mainland China and according to data I got from…”
Alright thanks for watching and don’t forget to subscribe! 
Хобби
Born in '65. Had one and was fortunate to be able to string a long antenna. Worked well enough.
I had one too!
I hope Radio Shack comes back into business. They sold some of the best electronics parts . Also miss Heathkit .
OMG. I had one of these when I was about 10 year old. This exact model. The brass bead coil tuner we so cool.
Oh man, I built this exact kit (minus the dust) when I was just a kid growing up in NE PA. I think this is what I listened to Dr. Demento on!
Rock on, Dave!
Very beautiful model nice video
Thank you very much!
Yes, 51 years ago, I built my own crystal radio. I used a rock as my diode. It was a quartz crystal rock. And of course back then we wrapped the wire around the toilet paper cardboard. I also used part of an old landline telephone to use it as the ear phone. Fun times indeed.
I'm using the piezo buzzer from a talking smoke detector.
I truly miss the times when you could take some basic components -- stuff you could actually see with your eyes and touch with your hands -- and create some working device with clear understanding how it works.
Ostap1974 I hear you. When I was a teenager I didn't play ROCK BAND™, I played in a rock band.
amazing, you just tok me back in time to my many many visits to a Radio Shack, good times
wrongmower You and me both, brother.
Its ca. 25 years ago, my brother gets this radio set from grandpa.
3:50 You can use "Line in" or "Mic in" , too.
Greetings from germany
That was fantastic! Thank you. The maths always confused me, but this is so clear. Good job. :)
:)
Really cool man I love these videos
Steven Vincent Thanks!
IT'S SO COOL!
Thanks for sharing! I've made this one too! It works!!!🌞🌍👍
I look forward to finding a kit like that some day in the future.
Really pretty cool
4451ab I know, right? :)
Nice kit
I had this kit!!!
I bought this kit from a thrift shop for .50cents. I never got around to assembling it. Althou I lost track of the crystal kit, I modeled after it. The crystal radio works great. nd I don't have to use a ground.
Cool!
50 CENT???
I heared correctly?
Greetings from germany
I just bought this kit.. Great teaching tool. New old stock. Love eBay.
Very cool!
Would a dynamic microphone preamp work best with regular headphones to use with crystal set radios?
I had that when I was a kid it worked great
Me too! Except my Dad put it together and wouldn't let me play with it.
I built a different version of this back in the 70s. Mine had a plastic case to build it into. Ran an antenna wire out the end of the garage out my bedroom window. This simple type system can only work for am though.
FlashGeiger I'll bet Bill Gates and Steve Jobs built them back then, too... Not together.
If I understand it right, the ball has to make contact with the coil, just like in the case where a handle is used. It is therefore not a matter of magnetic lines being crossed?
My father had a CB with an amplifier and it used to make that thing shake upstairs in the house
Very cool!
So effective but where did you get this old kit ?
I think I still have mine.
Your first step to a Mr. Spock TV made with stone knife and bear skin technology. Run a wire to the chain link fence outside for an antenna.
Great tip!
What is the tuner ball made out of? And how do you make that coil so tight and clean?
Tuner ball is (I'm guessing) probably brass from the look of it.
Wind just like you see me do here - dont move the spool around the coil - rotate the coil to accept the wire right off the spool and slide into place as you go. Good luck!
Oh ok. Thanks! I'm trying to build my own after making one for a present. I thought this would help. :D
What gauge wire was that and how many feet was that .magnetic wire.,I just bought some very old cat whisker diodes,from a seller that found a small supply of the,and I also have have the modern one too ,to see which works better.
I never thought to measure the wire.
Probably about 26 gauge
Stubblefield coils produce their own current.
I built several different radio kits including this exact one, but I could never get it to work. I think my antenna was always too small.
Try some bare pipe or a barbed wire fence. Chain link might work too.
To bad the diagram of the crystal radio was not shown . The Diode is a 1N34a. Germanium diode. Silicone diodes will not work. I like the old 1n34s from way back. They are real cool looking.
does anybody know what is the best diodle to use for a crystal radio
crystal diode?
Luke Marlow n134
They still sell that same exact one.
Amazing.
My husband' has this hidden all over the house, what does this mean??
I want one! How mucho dinero?
Gary Mercer There's one for $25US on eBay. It's almost identical to this one (different box art) but I don't think I would recommend this model to my friends. It's a kids toy. And I've never done business on eBay so I can't recommend them either. I searched Amazon (whom I do business with) but all they had was kids stuff, too. Just Google "Crystal Radio Kit for sale" and see what you like. Maybe there's a hobby shop near your home.
Good luck and thanks for commenting!
Where can I find this kit
Try your local hobby shop
@@repairs101 thank you
Could have done with a bit more of a listen!
how many realise the potential for free electricity here?
dont expect some major breakthrough in the world that brings this to you for free, you will be sold such a technology for more than it would cost for you to make yourself.
+james nichols - there's certainly signals enough out there to do something with. Reclaim the energy and reuse it to power more signals?
+james Nichols After further looking into this, the power they are harvesting is like static tiny. But it is nifty stuff. It would be nice if they taught stuff like this in school.
I make videos because they don't teach this stuff in school. Thanks for contributing!
Repairs101 how many of those crystal diodes can you use in one circuit? In my head I'm imagining a line of them recharging a battery. Is that possible? Also if this is possible can we harvest the "noise" from the big bang? If its strong enough to screw with our TV, is that strong enough to collect?
+james nichols well this is it
Pipes are not good these days, as they are made of polyethilene.