ARLA/CLUSTER: Recomendações da IARU para a Região 3

[João Costa > CT1FBF]

 IARU Recommendations

Dear Colleagues,

I should have sent out this notice much earlier, but please note the
recommendation below which has been agreed at the Region 3 Directors
meeting in Tokyo, August 2013.

<Quote>

At the Region 3 Directors meeting held in August 26th and 27th, 2013,
the following two recommendations were adopted regarding usage of two
meter band for the amateur satellite service.

1. It is recommended that the band 144-146 MHz (“two-meter” band) be
used exclusively for down link on all future satellites.

2. It is recommended that the 144.000-144.035 MHz section be
additionally allocated for satellite down link .

Background information

1. Usage of the band 144-146 MHz for down link only

The band 144-146 MHz (“two-meter” band) is, according to the Radio
Regulations, allocated to the amateur and the amateur-satellite
services world-wide on a primary basis with exceptions in several
footnotes. But by agreement of all three IARU Regions, currently only
a sub-section, namely 145.80–146 MHz of the allocation, is used on an
exclusive basis for the amateur-satellite service.

Although the band 145.80 – 146 MHz is presently used for both uplink
and downlink portions, the Cavtat Conference of IARU Region 1 in 2008
agrees to recommend its use for downlink-only to reduce interference
signals from non-amateur signals (illegal’s like taxis) being relayed
if it is used for uplinks.

The usage of the band 145.8 - 146 MHz reduces path losses by about 9dB
compared with usage of the band 435 - 438 MHz.

Most amateur satellites do not employ attitude control due to their
size and financial constraints, therefore the use of simple
omni-directional antenna would be popular. In this situation 9 dB pass
loss advantage is essential.

On the other hand, some societies in Region 3 have mentioned that to
avoid interference signals from non-amateur signals (illegal’s like
taxis) the band 145.8 – 146 MHz has not been used for downlinks in
most amateur-satellite services. But comparing effects of interference
caused by illegal signals on uplinks and downlinks, to avoid uplink
interference is important because many amateur satellites would be
affected if there is interference on uplink.

Taking into account these factors mentioned above, it is recommended
that the band 145.8 - 146 MHz should be used for downlink only in
Region 3.

2. Additional allocation of 144.000-144.035 MHz section for satellite
down link only

The IARU Satellite Advisory Group has been discussing the additional
allocation of the 144.000-144.035 MHz section for satellite down link
only taking into account the shortage of spectrum of 2m band for the
amateur satellite service .

In 2008 it appeared that very little EME was then taking place at the
very bottom of the 144 MHz band, due to interference from computer
oscillators. This section is already aligned worldwide and therefore
it was considered that this could be suitable part of the band to be
used.

More recent research and discussions suggested that this situation
remains the same today. Further research has concluded that the bottom
35% of the 2 metre band is almost completely unused.

It was noted that Region 1 had also discussed this matter and their
opinion was on similar lines.

This subject was also discussed at the Region 2 conference in
September this year and approved.

<unquote>

73 de Ken Yamamoto, JA1CJP
Secretary, IARU Region 3
secretary<at>iaru-r3.org

via NZART