The diagram right shows a typical system layout.  Click on the diagram to see it full size.

 

The hardest and most important decision in an installation is the location of the antenna.  A good location will provide a 360° view of the horizon

 

On a sailboat the obvious choices are any structure on the stern that will allow the base of the antenna to be 6-8 feet above the deck.   On a power boat a location similar to the VHF antenna will usually do.