Yes, but think before you cut. You will have to fit a new connector, which is not always easy. It might be better to leave the surplus length in a loose coil out of sight. If you want to lengthen the cable, Pacific Aerials has ready made cable packs with fitted connectors. If in doubt, talk to us.
The general rule is to install all antennas an antenna's length away from other antennas. If you can’t get that separation, install them as far apart as possible. If transmitting on your VHF causes interference on other marine electronic equipment, consider installing ferrite clamps around the equipment’s battery and connecting cables.
Pacific Aerials likes good looking installations too. Our fold-down mounts can be “handed” so the handle points are on both sides. Pacific Aerials’ mounts have cable entry holes, or are supplied with a cable entry cover, to make the installation look neater.
You can, but every degree that your antenna is off vertical decreases the performance of the antenna by 1%. Communications antennas should be vertical.
VHF and AM/FM antennas: As high as possible, with a clear all round view. Antennas work on a "Line of Sight" basis. The higher your antenna is, the further it can "see'', meaning a greater range for your communications.
Cellular: There is a compromise between getting the antenna as high as possible, and keeping the coaxial cable run as short as possible. At cellular frequencies, the signal strength losses in the cable are high. For example, a 25m run of standard RG-58A/U cable would result in losing 88% of the received (and transmitted) signal. Pacific Aerials has special low loss cable packs where longer runs cannot be avoided.