While most terrestrial radio frequencies are restricted or require a license from FCC, the FCC has set aside some frequencies for unlicensed, free usage by the user. For environmental data communications, the term “spread spectrum” is often associated with unlicensed frequencies.

The FCC allows the use of spread spectrum technology in three radio bands, 902-928 MHz, 2400-2483.5 MHz and 5752.5-5850 MHz for radio transmission under 1 Watt of power. This power limit prevents interference within the band over long distances.

Reprinted with Permission from Stevens Stevens Water Monitoring Systems