Just tape up the door and fender open the door all the way .Go and buy a 10MM swivel gear wrench .It will be worth it
Take all the 10s out of the jam one is holding the antenna with the slotted hole .Also take about half out in the wheel well.
Pull the bottom of the fender out carefully and drop the antenna out after unplugging, attach a wire the the plug to fish the new one up .