This crystal oscillator is indicated for the calibration of IF steps of common radio receivers. The transistor admits equivalent as 2N2222 or BF494. The circuit is from an old American publication.
The coil of this receiver determines the range. It can have 2 to 10 turns of wire 20 to 24 in the...
This circuit has tone control, and its power depends on the supply voltage. The circuit is from...
This circuit with 10 MHz and 1.25 MHz TTL outputs was found in an American documentation from the...