Antenna lead/coax wire question

[donbryce]

In the course of pulling unused and cut antenna leads from my newly acquired 560SL, which had no less than 3 of them, including (thank goodness) the original lead from the old Becker, I discovered something interesting.
I was using my multi-tester to check the continuity of the wiring found tucked away in the body and routed around so I could only see the ends of the wires, at first. I later checked the cables individually and out of the car. In each case, I could get a continuity reading (00 ohms resistance) on the outside sheathing only, the braided wire. None of them gave any reading for the inner wire! I even tested an extension lead, using a nail inserted into the female end, and still could only get a reading on the outer braiding.
All of these leads seem to work OK, especially the stock cable, which I connected to the Alpine HU. The inner wire on one is copper. Why couldn't I get a continuity reading on this inner wire????

[Rick76]

Some antenna cables have a series capacitor installed to pass only RF. DC and low frequency AC are blocked. They will look like an open circuit if tested with an ohmmeter.