U-NII

The Unlicensed National Information Infrastructure (U-NII)radio band is part of the radio frequency spectrum used by IEEE-802.11a devices and by many wireless ISPs. It operates over four ranges:

Wireless ISPs generally use 5.725-5.825 GHz.
In the USA licensed amateur radio operators are authorized 5.650-5.925 GHz by Part 97.303 of the FCC rules.

U-NII is an FCC regulatory domain for 5- GHz wireless devices. U-NII power limits are defined by the United States CFR Title 47 (Telecommunication), Part 15 - Radio Frequency Devices, Subpart E - Unlicensed National Information Infrastructure Devices, Paragraph 15.407 - General technical requirements. Regulatory use in individual countries may differ.

The European HiperLAN standard operates in same frequency band as the U-NII.

Except where noted, all information taken from Annex J of IEEE 802.11-2007 modified by amendments k, y and n. Because countries set their own regulations regarding specific uses and maximum power levels within these frequency ranges, it is recommended that local authorities are consulted as regulations may change at any time.

In 2007, the FCC began requiring that devices operating in channels 52, 56, 60 and 64 must have Dynamic Frequency Selection (DFS) capabilities. This is to avoid communicating in the same frequency range as some radar. In 2014, the FCC issued new rules for all devices due to interference with government weather radar systems. Fines and equipment seizure were listed as punishment for non-compliance.

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