Parts used are a moulded inductor, a 2200pf capacitor, a MW loopstick antenna, a PVC gang condenser and a germanium diode. The enclosure is a 3" x 3" x 1½" electrical bakelite box.
 |
| Ferrite Loopstick Crystal Radio |
 |
| Ferrite Loopstick Crystal Radio - Schematic |
Screw terminals are provided on the rear of the enclosure for connecting the antenna, earthand headphones. Headphones used are of the sensitive, balanced-armature type.
 |
| Inside the Ferrite Loopstick Crystal Radio |
The loopstick is 125 turns of Litz wire close-wound on a 2" length of ferrite rod with a tap at 25 turns. The number of turns may vary depending on the diameter of the ferrite rod and its relative permeability.
The primary series-tuned circuit consists of the 200μH moulded inductor, the 2200 pf capacitor and the capacitance of the 60' wire antenna. The secondary is parallel-tuned.
Reception is as good without an external antenna and earth, when the radio is held close to a CATV cable running over the shack and working as a passive radiator. Signal strength is maximum when the ferrite rod is laterally oriented with respect to it.
Related: Permeability-tuned Crystal Radio
_______________________________