2013年1月1日星期二

Choose 2 way radios

Want to stay in touch with your skiing pals dispersed all over a mountain? Need to check in with hiking partners traveling at a different pace? 2 way radios—rugged, lightweight, compact—are designed for such tasks.
How well do they work? Here are some tips to help you set realistic expectations and decide which model is right for you.
Q: What types of 2 way radios are available?
A: You can choose from 2 configurations:
1. FRS (Family Radio Service) models—lower-power units that operate with a half-watt of power. They can transmit on 7 FRS channels and 7 shared FRS/GMRS channels (channels 1-7)—a total of 14 channels.
2. GMRS (General Mobile Radio Service)—higher-power radios that, for models used in outdoor recreation, typically offer 1 or 2 watts of power. GMRS signals can travel on any GMRS or FRS bands—a total of 22 channels.
Most radios now have all 22 FRS and GMRS channels available. The Federal Communications Commission (FCC) requires a five-year license to use GMRS bands. More details about these 2 types of radios can be found later in this article in the “Channels and Privacy Codes” section.
Range of Coverage
Q: Range claims (“Up to 25 miles”) are often prominently displayed on packaging. How realistic are such claims, and how important are they?
A: High range claims are based on transmissions in optimal conditions. This means having an unobstructed line of sight between you and another radio operator, preferably from a high vantage point in good weather.
Real-world conditions, though, are usually not optimal, and the range of a 2 way radio is commonly much less than the maximum possible.
So what is realistic? Regardless of a unit’s published optimal range, in roughly 90% of situations (including activities in wooded or hilly terrain), a radio’s actual range will be about 2 miles or less.

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