ARLA/CLUSTER: Anuncio da coordenação da IARU para as frequências dos satélites de amador

[João Costa > CT1FBF]

IARU Coordination of Satellite Frequencies

The *IARU* have annouced they are committed to only coordinate satellite
frequencies within the internationally aligned IARU band plans

The two metre amateur band is one of the most popular and populated bands
in all the spectrum allocated to the amateur and amateur satellite
services. This recently 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 Satellite Adviser, Hans van de Groenendaal, ZS6AKV and his
advisory panel are mandated to coordinate frequencies within the IARU band
plans for amateur satellites. 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. In theory satellites could be programmed so
that they only operate over their country of origin.  Because satellite
orbits make it difficult to pinpoint operations, spill over 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 offers frequency coordination in an effort to maximise spectrum
utilisation and avoid possible interference to other satellites and ground
stations.

The IARU requests that satellite groups work on a sharing plan or use other
parts of the amateur service spectrum designated for satellite operation.
When a large group of satellite sharing the same band are 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
initialising transponders and other systems.

For instance, the 10 metre band, once popular with satellite builders, is
today not significantly used. 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 communications
satellite, in 1972.  The band segment was very popular for downlinks in the
1970s and 1980s.  Today, only one amateur satellite actively uses a 29 MHz
downlink: AMSAT-OSCAR 7, launched in 1974 [and RS-15 on 29.3525 MHz
<https://www.youtube.com/watch?v=Gf8t2O2ytbo> - Editor]. While a 29 MHz
downlink would not be practical for today’s very small satellites, owing to
the size of the antenna required, the band could be used very practically
for uplinks even with small receiving antennas, because transmitting power
at the earth station is easy to obtain.  The IARU Satellite Adviser and his
panel believe that the 10 metre band offers a good alternative to 2 metre
uplinks.

Currently the IARU team also coordinates frequencies for satellites built
by universities and educational groups in an effort to maximise spectrum
utilisation and mitigate any possible interference to Amateur Radio
operations. The IARU is committed to work with these groups and with the
ITU to find other spectrum for these satellites.

* Rod Stafford W6ROD*
Secretary
International Amateur Radio Union (IARU)

Two US Naval Academy satellites PSAT and BRICsat launched May 20, 2015 both
have transponder uplinks on *28.120 MHz*. Another US Naval Academy
satellite PCSAT-2, which is currently undergoing coordination by IARU,
plans to have a transponder uplink on *28.120 MHz*.

IARU Satellite Frequency Coordination pages http://www.amsat.org.uk/iaru
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