The local 200 kW, 612 kHz AM broadcast station, located 20 km away as the crow flies, is quite readable on this simple crystal radio employing a ferrite loopstick antenna (with its broadside oriented in the direction of the station) and balanced-armature phones.
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| Ferrite loopstick antenna |
The loopstick comprises 12 pieces of 4" long, 3/8" diameter ferrite rods stacked inside a 1½" diameter paper former.
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| Crystal radio with a ferrite loopstick antenna - Schematic |
The coil is 33 turns of PVC insulated copper wire (wire overall diameter 1/12"). It is tuned using a 500 + 500 pf variable capacitor with its sections connected in parallel.
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