Hi Drew,
Thanks for your report! I think the problem is not lack of electric energy, CAS-2T is an 2U structure, we installed solar panels on five sides with 30% efficiency, average total power about 2.2 Watts, the power budget: CW Beacon=0.5W, FM Transponder=0.7W, OBC=0.05W, TT&C Receiver=0.12W, Total=1.37W, normally there is some superfluous power to supply to heating resistances.
What problems are I think: First CAS-2T was not separated from the launch vehicle, final stage of the lauch vehicle is much bigger than CAS-2T satellite, and it keeps self spin in approx. 7 seconds per circle. It lead to the antenna radiation pattern becomes chaotic, the gain at some positions become much lower and is accompanied by a parasitic amplitude modulation. On the other hand, in order to avoid chaotic signal on VHF from land in East Asia to disturb the Satellite uplink , we adjusted the uplink receiver squelch at very deep position, it makes the transponder opening sensitivity less than -110dBm at RF input port of the receiver.
So I think the solution is only to improve the uplink EIRP, some of the high schools' club stations here using 3 meters boom antennas with approx. 50W RF power to get through the transponder well.
73 Alan, BA1DU
At 2016-11-19 08:29:06, "Andrew Glasbrenner" glasbrenner@mindspring.com wrote:
Hi Alan,
I have listened to CAS-2T on several passes now. I can make the repeater transmitter come on by transmitting on the uplink, but as others have pointed out, nothing is repeated. The downlink is intermittent and choppy, with no audio apparently passed through. It almost sounds like older handhelds would sound on transmit with a low battery. I wonder if it's possible to try turning the CW beacon off? It would be great to recover the satellite, as it is in a very nice orbit!
73, Drew KO4MA
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Alan Kung Sent: Wednesday, November 16, 2016 10:58 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Info of Chinese Launch 2016-066
2016-066D Satellite Name: TY-1 Mission: Technical experiment TT&C: 437.5MHz Bandwith 300kHz
2016-066E Satellite Name: CAS-2T(Dream-1) Mission: Education, Amateur radio, Technical experiment CW Beacon: 435.710MHz FM Transponder Uplink: 145.925MHz FM Transponder Downlink: 435.615MHz
2016-066E Satellite Name: KS-1Q Mission: Technical experiment TT&C: 436.5MHz 20kbps GMSK
2016-066F Satellite Name: Pegasus-1 Mission: Technical experiment TT&C: 468.0MHz FSK
73 Alan, BA1DU Chinese Amateur Satellite Group(CAMSAT) _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb