Provided are a wireless disasters-preventing node and system which enables to judge the degree of congestion of an operating frequency channel due to another system and to allow a user to know an unused frequency channel of low communication frequency. A first utilization rate measurement part (40) measures the utilization rate of the operating frequency channel, and a second utilization rate measurement part (42) measures the utilization rate of the unused frequency channel. In occurrence of congestion wherein the utilization rate measured by the first utilization rate measurement part (40) exceeds a predetermined value, a first utilization rate judging part (44) displays, as a recommended switch destination, the unused frequency channel of a low utilization rate judged by a second utilization rate judgment part (45).
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