Setting up a new Firestik no ground plane side mount on a fiberglass roofed vehicle. First test I wanted to do was to ensure no continuity on the center wire of the antenna cable.

I have no continuity until I connect it to the radio, then continuity. Disconnect the radio from battery and Continuity goes away. This is with a President CB.

Is it my understanding of what's is correct or is it something else that is off? I am expecting no continuity and this will contribute to high SWR. I want to tune the antenna and get no variance when I adjust the tip and _assume_ it is because the antenna is grounded when connected to the radio.

I'm a very amateur amateur radio operator, your help is appreciated.

Thank you.