what am i doing wrong??

[550cummins]

ok so i went another route with the antenna today and mounted it to a piece of mast pipe and then mounted the pipe to the bed of the truck. went through and grounded the mount to the frame of the truck and i am having a new problem.

when i hook my meters up from jumper to antenna i get a good swr. but when i hoot the jumper up to the radio and the longer coax going from antenna to meter my SWR is screwed. went through and had this reading with 2 different sections of coax thinking maybe the coax was bad but still the same results.
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[Lost Ram]

If I changed coax lengths and the SWR changed I would lean toward a Common Mode problem. This is when the signal is being radiated out of the coax and the antenna like its one long antenna. Make a few loops(5" diameter or so will be fine) of the coax at the bottom of the antenna and see if you get the same reading. I assume you will not, this may indicate you have a ground issue. Also how high is this pipe away from the body of the truck? And what type of antenna do you have? Your antenna may just be to far above the body line as well.