Hi swr is no fun sounds like it's the mag mount coax is been used a ground or the mag mount has had water in the mag and dryed up I had the same problem with the mag for my 4000 hi power so had a look to see all the screws had no rubber seal on every screw to stop water getting in so opened it up and it had water in and it was very green one side of the coax the ground side was hot glue and the transmitt side was green and just ready to fall off so new coax cleaned and coax soldered back back on a new seal for the top of the mag and new o rings check swr and its swr is very good infact better now hope you find and fix it your swr
Hi swr is no fun sounds like it's the mag mount coax is been used a ground or the mag mount has had water in the mag and dryed up I had the same problem with the mag for my 4000 hi power so had a look to see all the screws had no rubber seal on every screw to stop water getting in so opened it up and it had water in and it was very green one side of the coax the ground side was hot glue and the transmitt side was green and just ready to fall off so new coax cleaned and coax soldered back back on a new seal for the top of the mag and new o rings check swr and its swr is very good infact better now hope you find and fix it your swr