High SWR on roof installed 3/8 through hole NMO mount

[WSJK800]

Hello, I recently installed my new GMRS radio and getting high 3 to 3+ SWR readings using the Midland Ghost and the Midland 32" whip antenna in an open area. When I connect the magnet antenna that came with the radio, I have a 1.3 SWR. The NMO mount is 3/8 through hole and mounted in the center of my Tacoma roof. The radio is powered direct to battery both positive and negative. The base of the NMO mount has ground continuity with the outside threads of the PL-259 female on the radio. The mount has good continuity with the shield/outside and center conductor on the PL-259 at the end of the cable with no shorts. I do get a short between shield and center conductor when I screw on either antenna. I'm thinking maybe the coax was compromised somehow during installation and I'm facing pulling the headliner down again and installing a new mount. I'm in San Diego if anyone works on these things and would be happy to pay a professional to get it right. Any advice would be appreciated.

Here's my setup:

Arcadian MABVT8U: 3/8 Thru-Hole NMO Mount with 17 Ft. RG-58/U Cable

MicroMobile® Ghost 3dB Gain NMO Antenna - MXTA25

MicroMobile® Whip 6dB Gain NMO Antenna - MXTA26

MXT575 MicroMobile® GMRS 50-Watt Two-Way Radio - MXT575

[WRUE951]

32 minutes ago, WSJK800 said:

Hello, I recently installed my new GMRS radio and getting high 3 to 3+ SWR readings using the Midland Ghost and the Midland 32" whip antenna in an open area. When I connect the magnet antenna that came with the radio, I have a 1.3 SWR. The NMO mount is 3/8 through hole and mounted in the center of my Tacoma roof. The radio is powered direct to battery both positive and negative. The base of the NMO mount has ground continuity with the outside threads of the PL-259 female on the radio. The mount has good continuity with the shield/outside and center conductor on the PL-259 at the end of the cable with no shorts. I do get a short between shield and center conductor when I screw on either antenna. I'm thinking maybe the coax was compromised somehow during installation and I'm facing pulling the headliner down again and installing a new mount. I'm in San Diego if anyone works on these things and would be happy to pay a professional to get it right. Any advice would be appreciated.

Here's my setup:

Arcadian MABVT8U: 3/8 Thru-Hole NMO Mount with 17 Ft. RG-58/U Cable

MicroMobile® Ghost 3dB Gain NMO Antenna - MXTA25

MicroMobile® Whip 6dB Gain NMO Antenna - MXTA26

MXT575 MicroMobile® GMRS 50-Watt Two-Way Radio - MXT575

well, assuming your magnet mount used as a reference is using a different cable. I would start looking at the cable or connectors.   And try moving your ghost antenna to the mag mount and check that.  If you see the same poor SWR than the antenna is suspect..  Process of elimination is the game.  Try reading in one set of circumstsnces than anoter as i suggested.  It's not always easy to chase poor swr problems..