Jim202 wrote:I once used one of those antennas. Found the VHF antenna was very sensitive to cable
length and how the SWR turned out. Don't be surprised if you have an issue trying to
match to that antenna.
It will take several tries with different length cables to fine one that will work with a
low SWR. When you remove the power meter, expect everything to change again.
Jim
You obviously had a bad or improperly installed antenna and you were just tuning the coax to match a bad load.
Those antennas need a good ground plane. You need to remove the paint from the roof in the contact area and bolt it securely.
I don't know about current practice on the major RRs but, back in the Penn Central days, the Radio Maintainers were not allowed to install or replace those antennas. It was considered a locomotive safety appliance and had to be done by the shop mechanical people. All the Maintainer could do was connect the coax.