The FCC requires that all vessels in the United States must have marine transmitting equipment certified under Part 80. Marine radiotelephone devices, such as VHF and DSC controllers, are very important when a vessel travels 20 to 150 nautical miles from the nearest land. VHF is a line-of-sight. It requires clear, reliable communication over short distances. With DSC controllers, yacht owners can streamline sending and receiving emergency and distress messages.
All vessels are required to monitor the emergency channel 16 at all times when at sea. The VHF operates at 156–162 MHz. VHF must be tested frequently before and after operations. VHF is tested for both forward and reflected power, with 25 Watts or more for forward power and less than 3 Watts for reflected power.