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ARRL General Bulletin ARLB012 (1997)

ARLB012 FCC proposes changes in spread spectrum regs

ARRL Bulletin 12  ARLB012
From ARRL Headquarters
Newington CT  March 5, 1997
To all radio amateurs

ARLB012 FCC proposes changes in spread spectrum regs

Responding to a petition for rulemaking from the ARRL, the FCC has
proposed in WT Docket 97-12 to adopt changes in its Amateur Service
rules governing spread spectrum.  In spread spectrum the energy of
the transmitted signal is distributed among several synchronized
frequencies within a band and reassembled at the receiving end.
This reduces power density and duration of a transmission on a
particular frequency and lets spread spectrum almost invisibly share
the same spectrum with users of other, narrowband modes.  Spread
spectrum also provides for improved communication under poor
signal-to-noise conditions and in selective fading and multipath
environments, and the ability to accommodate more communication
channels operating simultaneously in the same spectrum.

The League's December 1995 petition asked the FCC to relax its rules
to give Amateur Radio more opportunities to contribute to the
development of spread spectrum techniques.  Specifically, the League
sought to have the FCC relax restrictions on spreading sequences and
asked for greater flexibility in spreading modulation.  In response,
the FCC now has proposed to drop rules restricting amateur stations
to transmitting only frequency-hopping and direct-sequencing
spreading techniques.  As requested by the League, the FCC also has
proposed to require automatic power control for spread spectrum
transmitters, to ensure use of the minimum power level needed to
carry out communication.

The FCC also went along with the League's request to permit brief
test transmissions using spread spectrum and to allow international
spread spectrum communications between amateurs in the US and those
in countries that allow hams to use spread spectrum.  The current
rules allow only domestic communication.

The use of spread spectrum techniques was first approved for Amateur
Radio in 1985 for bands above 225 MHz and at power levels up to 100
watts, and there has been some experimental amateur operation since
then.  The FCC also has authorized Special Temporary Authority (STA)
in some instances to allow broader SS experimentation.  Since spread
spectrum was introduced in the Amateur Radio service, commercial
spread spectrum applications have been developed, including personal
communication services, remote meter reading and position locating.
But, the League had argued that rules limitations held back further
spread spectrum experimentation.  No changes are proposed in the
frequency bands where spread spectrum is permitted.

The FCC said the rule amendments would ''increase spectrum efficiency
and allow amateur operators to contribute to technological
advances.''  Comments on the NPRM in WT Docket 97-12 are due May 5,
with reply comments due June 5.


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