Register Account

Login Help

ARRL General Bulletin ARLB046 (1998)

ARLB046 FCC amends rules for U-NII devices on 5 GHz

ARRL Bulletin 46  ARLB046
From ARRL Headquarters
Newington CT  June 26, 1998
To all radio amateurs

ARLB046 FCC amends rules for U-NII devices on 5 GHz

The FCC has amended its rules for Unlicensed National Information
Infrastructure (U-NII) devices operating in the 5-GHz range under
Part 15 of the Commission's rules. In 1997, the FCC made 5.15 to 5.35
and 5.725 to 5.825 GHz available to U-NII devices under Part 15 of
its rules. Amateur Radio shares part of the spectrum involved, from
5.650 to 5.925 GHz. U-NII devices would provide short-range,
high-speed wireless digital communication.

In response to industry petitions for reconsideration and
clarification, the FCC has amended Part 15 to permit fixed,
point-to-point U-NII devices in the 5.725 to 5.825 GHz band to
operate with up to 1 W maximum transmitter output power and
directional antennas of up to 23 dBi gain. The Commission will
specify transmit power limits as a function of the channel bandwidth.
A logarithmic equation would determine the power permitted. ''This
action will not increase the maximum power permitted by U-NII
devices, but merely scale permissible maximum power to the bandwidth
used,'' the FCC said.

The FCC said it will consider higher gain antennas for U-NII devices
for longer-range community networking. In its comments, the NTIA
expressed concerns that high-power government radar systems could
interfere with the unlicensed devices, but otherwise supported the
use of higher-gain antennas for fixed, point-to-point U-NII devices
in that band.

The ARRL has argued that longer-range links will interfere with
amateur operations and are a significant departure from Part 15,
which requires that interference potential of unlicensed devices be
subject to ''reasonable regulation'' so as to not interfere with
licensed services. One industry petitioner, Apple Computer, said the
ARRL has not demonstrated that U-NII devices present any real threat
of interference to ham operation.

The FCC said it would maintain the power spectral density limits
adopted in the original report and order.

The FCC also revised its rules to express U-NII out-of-band and
spurious emission limits in terms of absolute radiated power levels,
regardless of antenna gain.

The FCC advised manufacturers ''to consider the proximity and the high
power of non-government licensed radio stations,'' including amateur
stations, when choosing operating frequencies during the design of
their equipment.

The complete text of the FCC Memorandum Opinion and Order, released
June 24, is available on the FCC Web page at


Instragram     Facebook     Twitter     YouTube     LinkedIn