ARRL

ARRL General Bulletin ARLB095 (1998)

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ARLB095 ARRL Petitions FCC for LF Allocations

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ARRL Bulletin 95  ARLB095
From ARRL Headquarters  
Newington CT  November 3, 1998
To all radio amateurs 

SB QST ARL ARLB095
ARLB095 ARRL Petitions FCC for LF Allocations

The ARRL has petitioned the FCC to create two low-frequency Amateur
Radio allocations at 136 kHz and at 160 kHz.  ''These allocations
will permit experimentation with equipment, antennas, and
propagation phenomena in a small segment of the radio spectrum that
has not been available to the Amateur Service for many years,'' the
League's petition declared.  The petition was filed with the FCC
October 22.

Specifically, the League has proposed permitting CW, SSB, RTTY/data,
and image emissions for amateurs in a 2.1-kHz ''sliver band'' from
135.7 to 137.8 kHz and in a 30-kHz segment from 160 to 190 kHz.  The
135.7 to 137.8 kHz band adheres to the European Conference of Postal
and Telecommunications Administrations (CEPT) band plan.

The ARRL has proposed allowing a transmitter output in both LF
segments of 200 W PEP, but in no case greater than 2 W EIRP
(effective isotropic radiated power).  The League's petition points
out that poor antenna efficiencies and ground-loss characteristics
likely would keep EIRPs at less than 1 W.  The two bands would be
available to General and higher licensees.

Unlicensed experimenters--some of them hams--currently operate on LF
in the US under the FCC's Part 15 rules.  These limit transmitter
input power to 1 W and impose substantial restrictions on the size
of the antenna.  The proposed allocations ''will provide the only
low-frequency allocation for amateur use and will accommodate more
flexible experimentation than is permitted under current Part 15
regulations,'' the League's filing said.

Hams would be secondary to the Fixed and Maritime Mobile services in
the 136-kHz allocation, and secondary to the Fixed Service in the
160-190 kHz band.  The League said its engineering surveys suggest
that hams could operate in the two segments without causing problems
to power line carrier (PLC) systems already active in that vicinity
or to government assignments.  Unallocated, Part 15 PLC systems are
used by electric utilities to send control signals, data and voice.

Calculations included with the League's filing demonstrate how
inefficient even relatively large radiators can be on LF.  For
example, at 200 W TPO (transmitter power output) and a 200 foot
vertical radiator, efficiency is only in the range of 1%, yielding
up to 2 W EIRP.  A more practical setup--200 W TPO into a 100-foot
vertical radiator (efficiency of 0.2%) would yield an EIRP of
between 10 and 40 mW.

Several countries throughout the world already enjoy LF allocations.
These include New Zealand, Great Britain, the Republic of Ireland,
and several European nations.

A copy of the petition is available on ARRLWeb, http://www.arrl.org.
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