What antenna should I use with what radio?

It depends on your needs and the amount of space that is available to mount the antenna/radio. Some considerations are: the height at which you can mount the antenna; whether you have to raise and lower it to fit under bridges, boathouses or other obstructions; and how far you need the transmitted signal to reach. The longer the antenna, the better coverage you can expect, generally speaking, if a larger antenna will fit on your boat. Always purchase the best antenna you can afford, since the antenna is the most important part of any VHF installation.