|Shortwave Crystal Radio - Schematic|
The circuit was 'breadboarded' on an old fan regulator baseplate with the coil wound on a white plastic pill bottle.
|Shortwave Crystal Radio|
Using a wire antenna (35' long) and earth resulted in 'local strong station breakthrough' and hum.
With earth disconnected, the breakthrough and hum disappeared and it was possible to tune-in to a faint shortwave broadcast. It was from AIR Chennai, on 7380 kHz, 300 km away.
Tuning further up, a weaker Oriental station was heard.
Severe fading was experienced with both the signals.
Similar results were obtained using a 1.5 m long telescopic antenna and earth.