VHF antenna mounts and Electrolysis

[donradcliffe]

As a newbie on the forum, I'll start with a warmup question. If I mount a SS VHF whip antenna to the masthead, the standard L-bracket mount makes an electrical connection from the ground shield of the antenna wire to the mast. Since the other end of the antenna wire shield goes to the radio and eventually the boat ground, I am concerned about electrolysis damage to the mast. The mast step is wired to the keelbolts for lighting protection, and I think the mast may be at a different potential than the boat ground. Is this a real problem, and does anyone have a suggested fix??