This pocket-sized VHF receiver was found in Radio Electronics magazine from January 1961. It uses a transistor and tunes to the 11-meter band, considered VHF at the time.
Great sensitivity for the circuit can be obtained with a Darlington amplification step for the...
This 2005 circuit was found in an English publication and can be implemented with virtually any...
This car alarm was found in an American '80s documentation. The circuit automatically activates...