Pete (AC7ZL) wrote in to tell us about his latest project: building a flat response microphone and channel amplifier. You may remember his previous project: building a crystal radio from modern junk. Sounds are "colored" by their surroundings; things like furniture, wall coverings, drapes and building materials all affect the way something sounds. To measure the effect that a space has on sound … [Read more...]
Crystal radio built from modern junk
November 16, 2005 By 18 Comments
[h. p. friedrichs] (AC7ZL) has some great plans for building a crystal radio. The stator coil and output coil are wrapped around the outside of a CDR sleeve. The tuning capacitor is constructed by sandwich two clear CDs between metal and attaching this inside the top of the sleeve. The rotor shaft is mounted using the bushings from a pair of disassembled potentiometers. A hot needle is used to tap … [Read more...]
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