The VHF (Very High Frequency) marine radio uses a FM (Frequency Modulated) signal band. All VHF radios used aboard boats are limited to a maximum of 25 watts of transmitting power. They must also have a front mounted switch which enables the user to change the power from 25 watts to one watt, for use when in close proximity to another boat or a marina that you are trying to contact via radio.
The best radio only works as well as the antenna to which it is attached. The VHF radio's range is pretty much limited to a line-of-sight range. Thus, a maximum range of about 25 miles is the best you can expect to get, due to the curvature of the earth. Again, much is dependent on the height of your antenna. The best VHF setup I've ever used is an ICOM M127 radio with an 18 foot tall, 9 decibel gain Shakespeare antenna.
Hand-held VHF radios are generally limited to a maximum of five watts of power, and also have a front mounted one watt switch. A word of caution about hand-held VHF radios: there's a big difference between water-resistant and water-proof. Water-proof is more expensive, but will prove to be a better bargain in the long run.
Recreational vessels under 65 feet are not required to carry a marine radio in U.S. waters. Neither the operator nor the boat, is required to have a license. If you are going to travel to a foreign country in your boat and carry a marine radiotelephone, a license is required.
For convenience and safety, a marine radio is one of the most important pieces of electronic gear that you can have aboard your boat. After the purchase of a good compass, you should walk over to the VHF radios in the ship's store and purchase one. With your radio, you can reach other boats, call marinas and, in an emergency, contact the Coast Guard.
If you have a radiotelephone aboard, in the United States, you are subject to Federal Communications Commission (FCC) rules and regulations. A marine radiotelephone is not a CB (Citizen's Band) radio, and the FCC consequently holds the marine radio operator to a much higher standard.
VHF radiotelephones transmit and receive on specifically numbered frequencies, much like TV channels. Some radio manufacturers boast that their unit has as many as 99 channels. This may be true; however, on a pleasure boat you are limited to certain channels that you may use for communication.
- Channel 16 is the distress channel and all boats should monitor this channel. If you have a serious problem on your boat, this is the channel to use for contacting the Coast Guard. For ordinary communications (non-distress calls), after contacting the party that you are hailing, you must switch to an agreed upon working channel for the rest of your call.
- Channel 9 is also a calling/hailing channel in some USCG Districts (District 9-Great Lakes is one). Note that this is a hailing channel, not the distress channel. Be sure to check with the Coast Guard to see if Channel 9 is allowed or required in your area.
- Channel 13 is used for contacting Bridge Tenders and Lock Masters.
- Channel 22A is a Non-distress working channel for communications with the Coast Guard.
- Channels 68, 69, 71, 72, 78A & 79 are Non-commercial Ship-to-Ship and Ship-to-Shore working channels.
- Channels 79A & 80A are non-commercial working channels for the Great Lakes only.
Note: Channel 70, which formerly was a working channel, has been withdrawn as a working channel and is now reserved for Digital Selective Calling (DSC). It is now illegal to use 70 as a working channel. So, even though you can access many other channels on your VHF, it is illegal for pleasure boaters to use them.
