Self Amalgamating Rubber Splicing Tape - 3/4 Inch 10 Yards General Purpose Waterproof High Voltage Self Fusing Electrical Insulating Tape

Change the coax for less loss. In my case the antenna is close to my radio so only needed about 10 feet. Shorter+better quality=lower loss. I might be totally wrong in that line of thinking, but thats the way I was taught many years ago. As to weather proofing, a bead of silicone around the box the antenna mounts to and wrap the connectors at the base of the box with this.. Those connectors will get water in them and degrade pretty quickly if you don't