Shakespeare makes some of the finest antennas in the world. The company is from Columbia, South Carolina but they are a global company. You can find their products in any good marine retail outlet. They have a marine line as well as a line of military grade products. These are serious antennas made for the worst conditions on earth.
The marine frequencies tend to be "line-of-sight" signals meaning that the distance that the signal caries depends on how high the antennas are mounted. For power boats that tend to stay on trim, the higher gain antennas produce better results.
Shakespeare's bread and butter are VHF antennas but they have developed an innovative line of cellular booster systems, high-end television antennas, and AM/FM antennas that we will mount to the aft mast. We have a complete compliment of Shakespeare antennas.
Shakespeare offers three grades of antennas: the Classic, Galaxy, and Phase 3. The classic antennas are fine but the Galaxy and Phase 3 offer a better finish, upgraded internal materials and better hardware. The phase 3 is the top of the line -- it has the best connectors and hardware which is better if you need to make long runs of heavier coaxial cable (like a LMR400). It will also stand up to salt water better. We used Galaxy grade VHF antennas because they mount directly above the wheelhouse where the runs are short and we can easily get to the antenna. We used Phase 3 grade antennas for AIS antennas mounted on the top of the A Frame and aft VHF antenna because they are more difficult to access.
It is possible to combine antennas with splitters. However, it is better to have one antenna for each communication device. This eliminates the possibility of interference between two devices. It also provides redundancy in the event one antenna gets taken out by a storm or bridge. And, lets face it, having a lot of antennas looks cool. So, we have one antenna for every device on the boat.
We have three VHF radios. Two radios are located in the Wheelhouse and the antennas will be located in the top of the Wheelhouse. One is located near the aft mast and the antenna will be located near the top of the aft mast.
We chose two 5309-R antennas. These measure 23 feet with a gain of 9dB. We are mounting them about 25 feet above the water so the total height is about 48 feet above the waterline.
We are using a 6225-R on the aft mast for our emergency backup system. This is an 8 foot antenna with a gain of 6dB. We will be mounting her about 50 feet above the water line. . .
We have two AIS radios. We have a Class A transmitter/receiver that connects to our navigation computer. We also have AIS receiver that plugs into our chart plotter.
We chose the phase 3 grade 6396-AIS-R. We are mounting one antenna at each end of the yardarm at the top of the forward mast. The antennas are 4 feet in length with a gain of 3dB. These are mounted about 56 feet above the waterline. And, about 4 feet from the radar and GPS.