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<DIV><!-- Converted from text/plain format --><FONT face=Verdana><IMG
src="http://www.amsat.org/amsat-new/echo/images/AO-51_Doppler.gif"><IMG
src="http://www.onlineradio.fr/wp-content/uploads/2009/07/AO-51.jpg"></FONT></DIV>
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<H1>Please Do Not use AO-51 while the satellite is in eclipse</H1>
<P><FONT face=Tahoma>After a brief outage on May 16, the AO-51 Command Team has
turned the AO-51 repeater back on, including the 67 Hz PL mode. </FONT></P>
<P><FONT face=Tahoma>The Command Team has a favor to ask of our Southern
Hemisphere users, including those in South America, Southern Africa, Australia,
and New Zealand:</FONT></P>
<P><FONT face=Tahoma>Please avoid using AO-51 while the satellite is
eclipsed.</FONT></P>
<P><FONT face=Tahoma>Most tracking programs indicate illuminated or eclipsed
states, and it can always be found by whether the footprint of the satellite is
crossing or in contact with the footprint of the sun. Generally this is
occurring when the satellite is South of 30 degrees South latitude at present.
AO-51 eclipses are predicted to reach almost 20 minutes by July 2010.</FONT></P>
<P><FONT face=Tahoma>AMSAT-NA VP of Operations, <STRONG>Drew Glasbrenner,
KO4MA</STRONG> said, "I realize this is a large favor to ask, but the
alternative right now is moving to a scheduled type operation, which I would
like to avoid. Please pass this to your friends, other users you know, and your
national satellite email lists and forums."</FONT></P>
<P><FONT face=Tahoma>For this summer eclipse season, the eclipsed periods are
while AO-51 is over mostly unoccupied Antarctica and surrounding areas. This
means when the batteries alone are supporting the transmitter there are not
likely to be any users. The power management software combined with the PL,
should mean the satellite's batteries can be protected from over-discharge,
while still providing the strongest possible downlink signal and highest
possible availability.</FONT></P>
<P><FONT face=Tahoma>Observations from the southern hemisphere while entering
and leaving eclipse are very helpful. Post your reports on the AMSAT-BB or
e-mail your report to the AO-51 Control Team via </FONT><A
href="mailto:ao51-modes@amsat.org"><FONT
face=Tahoma>ao51-modes@amsat.org</FONT></A><FONT face=Tahoma>. </FONT></P>
<P><FONT face=Tahoma>AO-51 operators also monitor the Live OSCAR Satellite
Status page (</FONT><A href="http://oscar.dcarr.org/" target=_blank><FONT
face=Tahoma>http://oscar.dcarr.org/</FONT></A><FONT face=Tahoma>). Analysis of
AO-51's Whole Orbit Data (WOD) files shows the distribution of the satellite's
users. See: </FONT><A href="http://tinyurl.com/2ehbxv5" target=_blank><FONT
face=Tahoma>http://tinyurl.com/2ehbxv5</FONT></A></P>
<P><FONT face=Tahoma>If the eclipse periods get too long too fast the repeater
may shut off due to a low battery voltage watchdog. If this happens, please
email Drew directly via </FONT><A href="mailto:ko4ma@amsat.org"><FONT
face=Tahoma>ko4ma@amsat.org</FONT></A><FONT face=Tahoma>.</FONT></P>
<P><FONT face=Tahoma>Read the latest AO-51 Control Team News at:<BR></FONT><A
href="http://www.amsat.org/amsat-new/echo/CTNews.php" target=_blank><FONT
face=Tahoma>http://www.amsat.org/amsat-new/echo/CTNews.php</FONT></A></P>
<P><FONT face=Tahoma></FONT> </P>
<P><EM><STRONG><FONT face=Tahoma>Drew,
KO4MA</FONT></STRONG></EM></P></DIV></BODY></HTML>