[amsat-bb] ITU Regions/ISS Radio System

["Frank H. Bauer" <fbauer@xxxxxxxxx>]

All,

The ISS Ham radios are Ericsson MP-X handheld radios.  We have programmed 
64 discrete channels in the radio.  Two of these channels on the 2 meter 
radio support voice operations (145.80 down/144.49 for regions 2 &3 & 
145.80 down/145.20 for region 1).  It was necessary to use two uplinks due 
to region-to-region restrictions on uplink frequencies.  We do not use a 
scanning capability on the radio.  The crew switches between one freq to 
the other.  If they begin a QSO over the US, they can track US stations 
until they hit the Atlantic and then they will quickly lose US 
stations.  They can then switch over to the other freq and pick up Europe 
or Africa.

There is an orbit prediction  capability on-board.  It is called 
Worldmap.  It is on the LAN-based computers in ISS.  The laptop we are 
currently using is not hooked up to the LAN, so Worldmap is not used near 
the radio system.  The Ham radio equipment is currently housed in the aft 
end of the FGB (Zarya). and, as described, is velcroed to the wall.

For a much more detailed understanding of the ISS Ham radio system, please 
refer to the paper shown at:  This paper is probably big for some that have 
low bandwidth internet capabilities.  The file is about 800K.

http://ariss.gsfc.nasa.gov/EVAs/amsat01.pdf

Enjoy!

Frank Bauer, KA3HDO
ARISS Chairman



Date: Tue, 6 Aug 2002 19:08:36 -0500
From: Estes Wayne-W10191 <W10191@motorola.com>
Subject: [amsat-bb] ITU regions

Scott Elliott wrote:

stupid question, but what is the difference between regions :).
i know (or at least think) england is reg 1, possibly the usa. but what is 
the difference.
also, looking at the freqs of the iss, that means that the crew have to 
change over freq when they are in range of a region 2/3 country, or does 
there little hand held allow reception on 2 freqs at the same time?

Wayne replies:

ITU region 1 is Europe, Middle East, Africa, and North Asia.
ITU region 2 is North and South America, Caribbean, Greenland.
ITU region 3 is South Asia and Oceania.

A quick search on Google found a nice map on the IARU web site:
http://www.echelon.ca/iarumsr2/ituregions.html 
<http://www.echelon.ca/iarumsr2/ituregions.html>

My guess is that ISS astronauts have to change channels on the handheld 
radio depending on
What region they are over.  Most likely, they put out a voice call on the 
global 145.8 MHz downlink, and then switch between the two uplink channels 
until they hear a response.  The radio probably isn't close to a window, 
and they couldn't necessarily tell what region they are over even if they 
were near a window because of clouds and/or darkness.

Wayne Estes W9AE
Mundelein, IL, USA
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