I am an over-the-road truck driver and have been a licensed ham since 1971. I want to use 2 meters in the truck but my antenna choices are limited since my truck belongs to the company I drive for. I have a 4 foot long Firestik CB antenna that I would like to cut down to a quarter wave on 2 meters. It's a simple fiberglass rod with a wire wound around the outside, covered with a PVC coating. While it's not an optimum performer, a quarter wave is fine for my purposes, I just need to know where to saw the antenna off. Do I cut it where the total (unwrapped) length of wire is 19", or where the rod is 19" regardless of how much wire is wound around it to that point?