Going mobile again

[alpha78]

ok guys this has been driving me nuts. mobile install fender mount on my jeep. doesn't matter if steel whip, 3' or 4' 5/8 wave FireSticks no matter what I do I get 1.6-ish on both Ch1 and Ch40, and then nearly flat match 1.1 on Ch20. Like an inverted bell shape curve. How. Why. Shouldn't the antenna be either too short or too long so one end or the other has the lowest SWR? Or was my radio tuned that way or something?

This is with my old super crappy Radio Shack meter and the antennas are all like 10 years old too. The radio is new. At this point I'm worn out twisting knobs and getting in and out of the jeep trying to get better results. Oh yeah, once I put the rubber plug on the tip then it all goes haywire and SWRS in the red! Take the plug off and everything's back to normal??? So I ain't using the plug.