How to Make a Homemade Radio

Factual Questions
1

Suppose Springfield, IL passes an ordinance banning the sale or posession of any and all communication devices; computers, TV’s, radios, etc., and the mayor sends her goons to confiscate them all, including mine.

Now wanting to miss out on my daily helpings of Toby Keith or The Dixie Chicks (there’s a country station in Decatur that comes in just fine :smiley: ), I decide to build my own, using materials readily available at home or from a nearby hardware store. Can it be done? What supplies would I need? And most importantly, how hard is it to do? I know that I can buy a 7th-grade science experiment kit that can probably walk me through the process (and has the components included), but we’re talking from scratch here. Is it possible to do with wires and other bits & pieces you can find lying around your home or in a hardware store?

2

if you can find old-style headphones:

http://www.crystalrad.com/schem.htm

see razor-blade radio

3

Here is a set you can build using purchased componants, including one diode, one resistor, and one earphone, and some wire, and an Oatbox. It also has links to more designs.

You can use crystals of galena, and a wire “Whisker” instead of diodes, if you want a classic piece, or even a black steel safety razor with a piece of pencil lead, if you want extra primitive.

You have to find a nice rusty razor blade, and let it sit in a cup of lemon juice over night, then wash that sucker good and clean in water, and dry it off without touching it. Wooden pencils with number two leads, sharpened good, then carefully pry apart the wood until you get about an inch long piece of pencil lead. Make that your “whisker contact” by winding a few turns of clean copper wire around it, and then using that wire to make your tank circuit. The pencil lead also serves as a resistor.

Fixed value capacitors can be made with waxed paper, and aluminum foil, wrapped in alternating layers, around a toilet paper roll. Variable inductance coils can be made with wire, and any plastic tube, using a nail core, or a larger piece of iron.

Experimentation will give you a better idea on just what size for each component gives you the best results.

Radio Shack has most of the pieces, and most of the short cut black boxes, and they also sell radios, too. Wire and nails are at the hardware store. Waxed paper and aluminum foil are at the grocery store. Beats me where you will find those old black razor blades. Galena is at the yuppie rock hound store.

Tris

4

But how does one make a suitablen earphone?

5

The crystal diode is very difficult to make. I’ve tried this before :D. Oh and for the earphone - just take the ear piece out of a old phone. The older the phone the better

6

“Oh and for the earphone - just take the ear piece out of a old phone. The older the phone the better”

But the OP specifies making the radio from items “readily available at home or from a nearby hardware” after the banning of “the sale or posession of any and all communication devices” which would include telephones. So taking the earpiece from an old phone is out.

7

Yes, these are great for AM, but what about FM*? Or shortwave?

How hard would it be to make one of those, so as to warn the rest of the country?

8

Ugh…

Could a Mod please fix that?

9

I’ve made, modified and used various crystal radios over the years. Could pick up clear channel stations from 1500+ miles away. My favorite diode replacement was a silver dollar, a pencil lead and a safety pin. Are silver dollars still considered readily available?

I was always intrigued by WWII POW stories of secret radios. I can see getting everything in a camp but 1 item: the earphone.

So far, no one seems to have come up with a suggestion as to how to make your own earphone. Requires permanent magnets, lots of fine ware, etc. Does anybody know how the POWs did it? (I assume that they might have bribed/swapped with a guard or civilian worker. Never underestimate the value of a Red Cross package in wartime.)

10

http://homepages.ihug.co.nz/~wradford/esphones.htm

I am not sure whether this fits the bill or not, though.

11

One way around the earphone problem is to just talk in Morse. You could hook your output up to a light bulb, or a buzzer (not all that difficult to make, givem wires and a piece of iron), or anything else that you can detect and read off dots and dashes.

I suspect that this is also what POWs did.

12

With a home made radio the best thing you can hear is the most powerful AM radio station in town. Out of town reception is out. So if the Mayor bans all communications, there’ll be no radio station to listen to.

But since you are so technical :

You can make a microphone from finely crumbled pencil lead granules brass metal cup and washers.

Crystal from a galena crystal placed in some molten lead, (lead is bad for u) with a cat whisker wire to make contact.

Build the tuning coil on paper tube,

The tuning capacitor from glass and aluminum foil,

Your earpiece from fine magnet wire on a perm magnet and a
metal baffle.