The purpose of this circuit is to measure the resistance of an antenna at the resonant frequency. The circuit is from an old American documentation for hams.
This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time...
This receiver receives signals from the VHF band with earpiece or application in a power stage. The...
This circuit, from an old ON Semiconductor publication, suggests a shield to excite an LED from an...