|Conventional Parallel-tuned Crystal Radio - Schematic|
|Parallel-tuned Series-fed Crystal Radio with |
Germanium Transistor as detector - Schematic
However, when the circuit was reconfigured as series-tuned and shunt-fed, there was a dramatic improvement in performance.
|Series-tuned, Shunt-fed Crystal Radio - Schematic|
|Crystal Radio using a 35mm film canister|
The local 612 kHz, 200 kW AM broadcast station came in real loud with just a 60' wire antenna. Headphone current, measured using a 1mA FSD 60 Ω meter, was 700 μA.
Subsequently, an improved, link-coupled, fixed-tuned version was built. The 50 turn link winding series-tunes the capacitive wire antenna to resonance at 612 kHz.
|Link-coupled, fixed-tuned version - schematic|
|Link-coupled, fixed-tuned version|