Many boats will have their masts down at this time of year and this provides the opportunity to take a look at the integrity of your vhf antenna system.
It’s a good idea to remove the antenna and take it home for safe keeping. Good quality antennas have a mechanical connection at the base, usually a PL259 connector, so it’s a simple matter to remove any protective tape or silicone and unscrew the connection. (Some economy antennas have factory crimped cable connections so you can’t separate them from the cable. If you have any doubt about the performance of such an antenna and cable you should discard the lot).
With the antenna removed you can have a close look at the cable and connectors. If there’s obvious corrosion at the connectors you’ll want to remove them and check that the cable isn’t blackened and corroded. If it is you might be able to retrieve the situation by cutting back to sound cable. If you don’t have sufficient slack to get rid of all the corroded cable you’ll need to replace it. Get marine quality cable with a stranded and tinned core and tinned braid with good coverage, over 90%. For runs longer than 6m you’ll want RG8X cable and for very long runs, 30m or more, you’ll want RG213.
Check with a multimeter that there is no circuit between the centre pin and the outer shell of the connectors at either end of the mast. If there is, you have a short in the system and you’ll need to track it down and replace the offending connector or cable. This test must be done with the antenna disconnected because most whip antennas show a dead short to a multimeter.
Finally, check that the cable inside the mast is not interfering with any internal halyards which could damage the cable. Most modern masts will have an internal conduit to keep rope and wire apart but some don’t, so check.