Some features of marine radios are standard or required. All radios (except handhelds) are required to have an operating mode called DSC. More on that later. All radios will have some degree of weatherproofing. They are designed to resist corrosion and UV light damage.
The two main factors you need to decide in selecting a marine radio is whether it is fixed mount or handheld, and the level of channel selectivity.
Fixed Mount or HandheldIf you are going to have only one marine radio on your boat, it should probably be a fixed mount radio. This radio will be attached to your boat, connected to your boat's electrical system and be connected to a large external antenna. The advantages are durability; you can't drop your radio if it is screwed down. Your boat's battery provides reliable power allowing your radio to use the full 25-watt legal output. Connecting to an external antenna gives you much greater transmitting range.
The handheld has advantages of being compact, portable, and independent of the boat's battery and antenna. The power output of a handheld is usually 5 watts. In an emergency, the redundancy of an extra radio could be crucial.
Handhelds may be the only choice for smaller boats lacking their own battery source.
SelectivitySelectivity is the ability of the radio to focus in on a specific signal and ignore the nearby signals. The greater the selectivity, the clearer you'll receive signals when the airwaves are crowded with signals, and the more you'll pay. The degree of selectivity you need greatly depends on your location.
Three specifications of the radio address the level of selectivity. Adjacent channel selectivity, spurious response rejection ratio, and intermodulation rejection ratio.
In remote areas with little radio traffic, a rating of 60 db for each of this specification would be sufficient. As radio traffic increases, you'll want higher levels of selectivity. A 70 db rating would be desired in high traffic ports, or near large cities. When you want top performance allowing you to clearly hear weak signals look for models with 80 db or more.
Handhelds usually have lower selectivity ratings than fixed mount. A good buy in handhelds is the Uniden Voyager. It is the smallest handheld made, but still has a selectivity rating of 70 db.
- Weather channel: Most radios are able to receive weather broadcast on VHF channels.
- Channel Scanning: A feature that will rarely be used.
- Hailer: Having a load hailer feature can be useful for some people. You can use your radio's microphone to connect to your boats external horn/speaker. This would be used for close ship to ship or ship to shore communication. Often used to "yell" at another boat going to fast in a no wake zone.
- Remote: Some models, like the Uniden UM525 and UM625 have the ability of being used by a wireless remote. Your fixed mount radio may be at the main helm, but you can access all of its features on the flying bridge with the wireless remote.
- Waterproof: All radios are water resistant. Some have even greater levels of water resistance including being submersible.
What is DSC?All fixed mount marine radios are required by law to have digital Selective Calling (DSC). With DSC a radio can send and receive digitally encoded distress calls on channel 70. Pressing the DSC distress button on the radio instantly causes a distress call to be sent out on channel 70. The digital message contains your unique identification number. If your radio is connected to a GPS, the distress call will also include your precise location making it much easier for help to find you. The distress call will continue to be sent until it is answered.
Searching for Marine Radios on eBayA simple search of eBay auction titles with the search words of marine radio will give hundreds of results. You can narrow your search by including a manufacturer's name. The two most popular manufacturers listed on eBay are Uniden and ICOM. A Uniden model having the same selectivity rating as a ICOM model will cost much less, making Uniden a much better deal.
Other Useful Marine Electronics Guides on eBay:
- VHF Marine Radio Antenna Buying Guide
- Fishfinder Buying Guide
- Pier, Dock, or Shore Fishing With a Wireless Fishfinder
- Marine Boat Compass Buying Guide