Peterbilt 389 with cab-mounted mirrors. K40 Open-helical coil, mounted to passenger side. Uniden 880 Bearcat. The SWR meter in the radio shows 8.5 on 1, 20, and 40. Not sure if this is a bad coax, or a bad mount. Previous antenna (simple factory-installed fiberglass whip and cheap coax) worked fine, no abnormalities. Going to try the other coax real quick, but figure any tips you guys might have for this mount would be welcome. Specifically, if it's this coax, should I just run the small-diameter one from the factory? Or purchase a new one here at the Love's? If it's grounding, how do I ground it out? From the mirror bracket to the frame? Thanks in advance for your help. Oh, and to head this off, tried searching and got a bajillion results arguing the merits of 389 glider kits, nothing for CBs that I could see.
I'd try buying/testing with some of the good clear coax. Wilson sells it in an 18' length. Hopefully you didn't have dual antennas before and are trying to use a co-phase harness with a single antenna. If that doesn't help, perhaps add the old antenna mounted downward from the mount with no coax attached to it to create a ground plane.
Disconnect the cable from the radio and check ohms from shield to battery ground. Should be zero ohms
To the original poster, are you using an external meter to measure the SWR? . . Did the original antenna have a good SWR reading when measured with an external meter? When you had the original antenna in your setup, exactly what did you change? Antenna, mount, coax? Go back to the original setup and change only one item at a time and re-check your SWR with an external SWR meter. . .If you are running one single antenna, you must use a coax with 50 ohms of resistance ie RG8, RG58, RG213 etc. RG59 is only used when you cophase 2 antennas. Length of coax does not have to be 18 feet unless you need that much to connect the antenna mount to the radio.
