Steady on guys!!
While the attempts to resolve the problem are admirable you can't just start drilling holes or installing unapproved equipment in an a/c.
In my opinion it's almost certainly the co-ax. VSWR can still show within limits for a degraded co-axial cable. Try slaving in a nice freshly made and checked cable and do the checks again. while you're at it check the bonding of the racks and the antenna too.