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</o:shapelayout></xml><![endif]--></head><body lang=PT link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US>ARISSat-1 low duty cycle mode<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>The new Amateur Radio satellite ARISSat-1 has been switching into low duty cycle mode, even while in full sun, which has suprised some observers.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>When the satellite is in darkness, in order to conserve battery power, it switches into a low duty cycle mode (also known as low power mode) where it transmits for 40 seconds and then shut down for 2 minutes. On Thursday, August 11, a number of Radio Amateurs reported that ARISSat-1 was in low duty cycle mode when the satellite appeared to be fully illuminated by the sun.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>On the AMSAT bulletin board Tony AA2TX, ARISSat SDX software and hardware developer. provided an explanation, he wrote:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>My analysis indicates that at certain "bad" sun angles, the solar panels may not provide enough power to run the satellite even in full sun.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>The power from the panels can actually drop to as low as 2.5 watts at really bad angles but the satellite needs around 8 watts average to run in high power mode. This means that the satellite would have to draw current from the battery to run in high power mode even though it is in the sun.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>This discharge would reduce the life of the battery so to minimize the damage and prolong the life of the satellite, it will switch itself to low power mode under these conditions.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>I don't know for sure if this is what is happening but this condition is within the predicted nominal operation of the satellite.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>ARISSat-1 Reception Certificates (for voice and Slow Scan TV reports)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>http://www.southgatearc.org/news/august2011/arissat_1_reception_certificates.htm<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Free Slow Scan TV Software MMSSTV uses your PCs Soundcard<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>http://mmhamsoft.amateur-radio.ca/<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>The IZ8BLY Vox Recoder software enables you to record ARISSat-1 on 145.950 MHz FM while you're at work or asleep<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>http://antoninoporcino.xoom.it/VoxRecorder/<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Online Satellite Pass Predictions, select ARISSat-1<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>http://www.amsat.org/amsat-new/tools/predict/<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal>ARISSat-1 Website<o:p></o:p></p><p class=MsoNormal>http://www.arissat.org/<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>AMSAT Bulletin Board (AMSAT-BB)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>http://www.amsat.org/amsat-new/tools/maillist/<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>AMSAT-UK publishes a colour A4 newsletter, OSCAR News, which is full of Amateur Satellite information.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Join online at http://tinyurl.com/JoinAMSAT-UK<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div></body></html>