Signal Detector (Field Strength Meter)
The thing that is horribly wrong that your transistors won't start conducting until the voltage at base reaches 1.3V. And that's a lot. You'll need to use either opamp with dual supply or a germanium transistor connected to a silicon one as a Sziklai pair.

EDIT: You can stay with your original circuit, just add some bias to the capacitor: connect the upper capacitor leg to the central point of a 10k:0.9k voltage divider, and connect the divider to +12 and ground.