Remember crystal radio sets anyone? : LUSENET : TimeBomb 2000 (Y2000) : One Thread

This will show my age, but does anyone here remember how to construct a crystal radio set?

Used these as a kid (my older brothers made them, I used them) to listen to radio programs in our bedroom at night. Parents did not know we were not asleep. Had earphones, of course. No electricity required.

-- Joe (, December 02, 1998


Search for some radio hobbyist's web-page.

-- Diane J. Squire (, December 02, 1998.

Edmund Scientific [] has a crystal radio kit.

-- Karen Cook (, December 02, 1998.

Also radiacs (Geiger counters) if you are so inclined.

-- Robert A. Cook, P.E. (Kennesaw, GA) (, December 02, 1998.

Crystal sets - I have built hundreds of them - they work best on really long antenna wires. Wind a wire coil of about 100 turns on an oatmeal box, then attach both ends of the wire to a variable capacitor of about 350 mmf max capacitance. One side of the coil/cap oscillator should now be hooked to a (very long) antenna, the other side to a good ground (copper water pipe or metal post driven into ground). A diode (1N34 is ok) is connected on the antenna side. Headphones are hooked between the unconnected side of the diode and the ground. This is your basic crystal set and should look something like this when done.

ground--|||coil|||------antenna-longer the better--- | | |_[vcap]_| | | | diode | | |__0~0___| headphones

Tune by adjusting the variable capacitor. You can also add taps to the coil by removing the insulation from the wire about every 5th turn and using a clip to attach the wire from the capacitor to the coil rather than soldering it. Then you can adjust the number of turns in the coil by moving the clip from one tap to another. The headphones should be high impedance magnetic type - between 500 and 5000 ohms - 2000 is probably best. I am told the new small magnetic headphones work well - haven't tried them so can't vouch for it from personal experience. Most parts should be available at Radio Shack - along with detailed instructions for building all sorts of hobby radio gadgets.

The most sensitive crystal type set I ever built had 4 diodes and a capacitor as the detector element for full wave detection with removal of the rf component. I got best results with a single transistor rf amp behind a coil/capacitor set for pretuning - with another coil/capacitor set for tuning behind the amp and before the detector - with a small audio amp driving a small earphone. Used to listen to Radio Netherlands out of the Antilles Island group - came in pretty good at night. Used a nine volt battery - but the battery would last almost to shelf life - months and months.

-- Paul Davis (, December 02, 1998.

Drat this browser - it removes carriage returns try this antenna-------------1N34-- 1N34 is the diode, hpn is = | | headphones c v h o c p i a n l p | = | | ground--------------------

try again

-- Paul Davis (, December 02, 1998.

Well drat again. Either put in the carriage returns in the above to get the diagram, or email me and I will scan one and send it to you, ok.

-- Paul Davis (, December 02, 1998.

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