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CX2SA > SPACE 24.08.15 18:24l 110 Lines 5341 Bytes #999 (0) @ ARL
BID : ARLS012
Read: GUEST
Subj: ARLS012 IARU Reiterates Commitment to Coordinate Satellites
Path: IW8PGT<CX2SA
Sent: 150824/1721Z @:CX2SA.SAL.URY.SOAM #:25964 [Salto] FBB7.00e $:ARLS012
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SPACE@ARL
Within International Band Plans
ZCZC AS12
QST de W1AW
Space Bulletin 012 ARLS012
From ARRL Headquarters
Newington, CT August 24, 2015
To all radio amateurs
SB SPACE ARL ARLS012
ARLS012 IARU Reiterates Commitment to Coordinate Satellites Only
Within International Band Plans
In apparent reference to efforts by China's Amateur Satellite Group
(CAMSAT) to coordinate operating frequencies for nine satellites set
to launch in early September, the International Amateur Radio Union
(IARU) has made it clear that it will not coordinate frequencies
that do not conform with accepted band plans for all three IARU
regions. The IARU has informed CAMSAT CEO Alan Kung, BA1DU, that it
was only able to coordinate uplink and downlink frequencies for two
of the nine spacecraft (CAS-3/XW-2D and E), but it has not made that
letter public. CAMSAT has said it plans to launch the nine
satellites, all carrying Amateur Radio payloads, on September 7 or
8.
"The IARU Satellite Adviser, Hans van de Groenendaal, ZS6AKV, and
his advisory panel are mandated to coordinate frequencies within the
IARU band plans for amateur satellites," said a public statement
released on August 20 by IARU Secretary Rod Stafford, W6ROD.
"Coordinated frequencies must comply with band plans that are common
to all three IARU regions. Satellites coordinated outside these
plans could cause interference to terrestrial amateur operations in
other regions."
The IARU statement suggested that the popularity and high occupancy
of 2 meters "led to a request by satellite builders for coordination
outside the spectrum reserved for satellites in the IARU band plans
(145.800-146.000 MHz), as not enough channels are available to
satisfy their requirements."
The IARU said that, in theory, satellites could be programmed only
to operate while orbiting above their countries of origin, but
"because satellite orbits make it difficult to pinpoint operations,
spillover to other regions may occur during parts of the orbit.
Accordingly, IARU will not coordinate frequencies for satellites
which are planned to operate outside the internationally aligned
IARU band plans for amateur satellites."
The IARU statement noted that its frequency coordination service
aims to "maximize spectrum utilization and avoid possible
interference to other satellites and ground stations." The IARU
recommended that satellite groups "work on a sharing plan or use
other parts of the Amateur Service spectrum designated for satellite
operation," and it suggested resurrecting 10 meters - once popular
as a satellite band, but largely unused today - as one possibility
for uplink channels.
"The band segment 29,300-29,510 MHz has been used for
Amateur-Satellite downlinks for more than 40 years, beginning with
Australis-OSCAR 5 in 1970 and AMSAT-OSCAR 6, AMSAT's first
communication satellite, in 1972," the IARU statement noted. Just
one amateur satellite actively uses a 29 MHz downlink - AMSAT-OSCAR
7, launched in 1974. Conceding that 29 MHz downlink frequencies
"would not be practical for today's very small satellites" due to
antenna size considerations, the IARU said the band could be used
for uplinks, even with small receiving antennas, because Earth
stations can run sufficient transmit power to overcome the
disadvantage. "The IARU Satellite Adviser and his panel believe that
the 10 meter band offers a good alternative to 2 meter uplinks," the
IARU said.
AMSAT President Barry Baines, WD4ASW, said his organization's
Advanced Satellite Communications and Exploration of New Technology
(ASCENT) initiative is exploring alternatives to address the
proliferation of CubeSats and the resulting pressure on 2 meters and
70 centimeters. He pointed out that the 200 kHz IARU allocation on 2
meters "is not very wide" given the number of satellites being
launched, but the use of 10 meters is impractical in this era of
CubeSats.
"It is incumbent upon the Amateur-Satellite community to develop new
ways of 'keeping Amateur Radio in space' that take advantage of
other bands and provide enhanced services through appropriate
technologies, given the need to find suitable bandwidth for an
increasing number of satellites," Baines told ARRL. He said using
digital technology could provide multi-channel capability, and
design work is already under way. Transitioning to "underutilized
amateur spectrum on bands such as 5 GHz and 10 GHz is also a
possibility, Baines added, although he was quick to point out that
AMSAT does not intend to abandon use of 2 meters and 70 centimeters
for its own satellite projects.
The IARU said that when a large group of satellite sharing the same
band is launched, "they will soon drift apart which enhances the
opportunity to share the same frequencies. For example, during the
initial phase, just after launch, a time-sharing system could be
used to monitor the payloads before initializing transponders and
other systems."
"Currently the IARU team also coordinates frequencies for satellites
built by universities and educational groups in an effort to
maximize spectrum utilization and mitigate any possible interference
to Amateur Radio operations," the IARU statement concluded. "The
IARU is committed to work with these groups and with the ITU to find
other spectrum for these satellites."
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