This circuit was found in a Radio Electronics from 1970. The coupler with LDR is from that time, but the circuit can be adapted to use modern components and act as a shield.
This 25 W phase photo control was found in a 1965 General Electric publication. The circuit uses a...
The circuit below uses common JFET transistors, which can be the BF245 or MPF102 amplifying video...
This circuit was found in a 1997 documentation. It works as a booster for VHF and UHF signals...