WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
On my Zenith tube radio, there are two terminals labeled G & F. Does anyone know what they are for? I am wondering if one is to hook up an external antenna. If case, to which one? What is the other one for?