We found this circuit in the Electronics Experimenter Handbook magazine from 1993. L1 has 2 = 2 turns of 28 or 30 wire in the shape of 0.5 cm without core. The range reaches a few tens of meters.
Found in a 1967 EEE, this circuit oscillates at 20 MHz according to the values of the given...
This circuit is from a 1980s Motorola documentation. The circuit can be made with modern...
This circuit is from Radio Electronics from April 1987. The circuit is powered with voltages that...