This shield circuit is from an American documentation from 1969. The components can be modified according to the relay and power, and the coupler can be of a modern type.
This circuit was found in an American documentation for radio amateurs of the 80's. The...
This circuit was obtained from the September 1971 issue of Radio Electronics magazine. The power...
The signals from this circuit obtained from the 1965 Radio Shack documentation are picked up from...