This simple circuit for the 3 to 30 MHz range was found in the Electronics Experimenter Handbook Special Projects of 1983. The coils consist of 10 and 50 turns of 32 wire on a 1 M x ½ W resistor.
This source was found in a 1982 American publication, but can be easily assembled using 2N2995 (PNP...
This contact or reed switch actuation was found in a 1964 Electronic Design. The circuit can be...
Found in a 1968 Electronics World, this circuit uses components from the era. In this circuit, a...