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This will be a collection of simple instructions on building an actual radio or two with household items. It will further demonstrate building one's own capacitor(s), and detector diode...again, from household items.
Some care will need to be taken when soldering and when working with items like razor blades, etc. but the careful person should have no difficulty in constructing these using the plans I will outline.
Some care will need to be taken when soldering and when working with items like razor blades, etc. but the careful person should have no difficulty in constructing these using the plans I will outline.
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We will build a few simple radios with this first in the series of Radio instructables.
The very first one, having only 2 parts to it.
Warning! This radio MAY NOT WORK in your area if there are no close by, strong stations. If you have a really close AM station, you may be able to get this to work. It is so simple though, that it is worth a shot.
First, find yourself a "piezoelectric" type earphone (not the magnetic and plate kind, they will not have the sensitivity needed).
Strip off the insulation (if there is a plug, it will need to be removed) from both wires.
Now, find yourself a 1N34A Germanium diode (low forward voltage, high sensitivity). solder the one wire of the earphone to the diode as in the schematic.
Now, tape (duct tape is good here) the other end of the diode to a water pipe (the facet at the sink is good), and grab the remaining free wire in your hand. You have now become the antenna, and the faucet the ground.
IF you hear anything at all, it should be a faint AM station.
There are 2 problems with this radio, actually at least 4 problems:
#1: it is not tunable, you can't "pick" the station you wish to listen to,
#2: it is not loud, IF you hear anything at all,
#3: it is not portable at all
#4: IF you have more then one station nearby, you will hear all of the strongest ones.
The very first one, having only 2 parts to it.
Warning! This radio MAY NOT WORK in your area if there are no close by, strong stations. If you have a really close AM station, you may be able to get this to work. It is so simple though, that it is worth a shot.
First, find yourself a "piezoelectric" type earphone (not the magnetic and plate kind, they will not have the sensitivity needed).
Strip off the insulation (if there is a plug, it will need to be removed) from both wires.
Now, find yourself a 1N34A Germanium diode (low forward voltage, high sensitivity). solder the one wire of the earphone to the diode as in the schematic.
Now, tape (duct tape is good here) the other end of the diode to a water pipe (the facet at the sink is good), and grab the remaining free wire in your hand. You have now become the antenna, and the faucet the ground.
IF you hear anything at all, it should be a faint AM station.
There are 2 problems with this radio, actually at least 4 problems:
#1: it is not tunable, you can't "pick" the station you wish to listen to,
#2: it is not loud, IF you hear anything at all,
#3: it is not portable at all
#4: IF you have more then one station nearby, you will hear all of the strongest ones.
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I have, inadvertently picked up AM stations on many devices though, not meant to receive such a signal, from digital recorders to home made buglar alarm systems....sometimes it is comical, but mostly it is just annoying :-)
My friend set-up the radio inside his house, and he got random signals from some random station which I can clearly hear when he stuck the earpiece up to the microphone on the telephone. He then set it up outside the house, but he surprisingly received weaker signals. I hypothesized the surrounding buildings may have somehow affected the signal, but we wouldn't know unless we demolished the entire block.
Pros:
-No need to fine tune into desired radio station
Cons:
-Carrying a box full of coils isn't really viable for portable sets, unless you really want to
Thoughts?
I have a box of coils, most of them are not really as useful as one might think. Since we are looking at the need for such a BIG coil, carrying a bunch of those around would be cumbersome (at very least ;-)
This is just the beginning of a couple (2 or 3 at least) in series that I will post links to one another inside the ibles, so anyone can find the others quickly, once they are finished.