This is an improved version of the previous circuit also found in the December 1990 Radio Electronics magazine. The duty cycle is also 50%.
Found in documentation from the 70s, this circuit uses an operational one from that time. It goes for...
This old 4-channel circuit was found in the December 1994 Electronics Now magazine. The circuit uses...
Found in a 1969 documentation, this circuit for the 20 MHz band does not use a transformer. The circuit is...