Range
The useful direct range of a two-way radio system depends on radio propagation conditions, which are a function of frequency, antenna height and characteristics, atmospheric noise, reflection and refraction within the atmosphere, transmitter power and receiver sensitivity, and required signal-to-noise ratio for the chosen modulation method. An engineered two-way radio system will calculate the coverage of any given base station with an estimate of the reliability of the communication at that range. Two-way systems operating in the VHF and UHF bands, where many land mobile systems operate, rely on line-of-sight propagation for the reliable coverage area. The "shadowing" effect of tall buildings may block reception in areas within the line-of-sight range which can be achieved in open countryside free of obstructions. The approximate line-of-sight distance to the radio horizon can be estimated from : horizon in kilometers = 3.569 times the square root of the antenna height in meters.
There are other factors that affect the range of a two-way radio such as weather, exact frequency used, and obstructions.
Read more about this topic: Two-way Radio
Famous quotes containing the word range:
“The Canadians of those days, at least, possessed a roving spirit of adventure which carried them further, in exposure to hardship and danger, than ever the New England colonist went, and led them, though not to clear and colonize the wilderness, yet to range over it as coureurs de bois, or runners of the woods, or, as Hontan prefers to call them, coureurs de risques, runners of risks; to say nothing of their enterprising priesthood.”
—Henry David Thoreau (1817–1862)
“Whereas children can learn from their interactions with their parents how to get along in one sort of social hierarchy—that of the family—it is from their interactions with peers that they can best learn how to survive among equals in a wide range of social situations.”
—Zick Rubin (20th century)
“The variables of quantification, ‘something,’ ‘nothing,’ ‘everything,’ range over our whole ontology, whatever it may be; and we are convicted of a particular ontological presupposition if, and only if, the alleged presuppositum has to be reckoned among the entities over which our variables range in order to render one of our affirmations true.”
—Willard Van Orman Quine (b. 1908)