SB NEWS @ AMSAT $SPC0426 * SpaceNews 26-Apr-99 * BID: $SPC0426 ========= SpaceNews ========= MONDAY APRIL 26, 1999 * UoSAT-12 LAUNCHED! * ====================== UoSAT-12 was successfully launched just before 0500 UTC last Wednesday morning from Baikonur. By Thursday, SSTL satellite operators at the Surrey Space Centre ground station in Guildford, Surrey, UK reported that their UoSAT-12 minisatellite had successfully passed the Initial Signal Acquisition phase. During this phase, the satellite's downlink was activated, on-board systems enabled and telemetry data received from all essential bus subsystems. Telemetry data received at Guildford and collected by co-operating AMSAT ground stations around the world indicates that all systems are operating as expected; received signals from the satellite are strong and the telecommand uplink is reliable. Thanks to DB2OS and VK5AGR for forwarding telemetry during this important phase of the mission. Operators have also uploaded flight software to the satellite's primary on-board computer. This multi-tasking software will collect telemetry throughout the satellite's orbit and support the Attitude Acquisition Phase of the mission. During Attitude Acquisition, on-board software will gradually bring the satellite to an Earth-pointing state. Simultaneously, operators will perform further satellite tests. Payload tests will start when the satellite is Earth-pointing. All indications from Surrey are that the ISC Kosmotras Dnepr launch was highly successful, delivering the satellite safely and accurately to orbit. The OBC is now running with the callsign UO120-11. The BBS is closed for general use at this stage although the downlink is on permanently on so stations can receive the downlink on 437.400 MHz FSK. Keplerian elements for UoSAT-12 have object number 25694. This is called SNAP-1 by NORAD but is actually UoSAT-12. Actually, SNAP-1 is a nano-sat that was to be launched with UoSAT-12 but was not launched. The object being tracked by NORAD is actually the shroud from the launcher. The following keps are correct for UoSAT-12: UoSAT-12 1 25694U 99022B 99111.87871775 .00019922 00000-0 30916-2 0 40 2 25694 64.5610 316.4522 0001414 11.6425 348.4724 14.73155686 88 [Info via Chris Jackson, G7UPN/ZL2TPO] * OSCAR-10 NEWS * ================= AMSAT-OSCAR-10 has come out of hibernation, and many reports have indicated that the satellite is performing quite well. Several groundstations are making digital contacts through AO-10's analog transponder using PSK31 modulation. PSK31 uses a baud rate of 31.25 and a bandwidth of 31 Hz and an alphabet similar to morse code with short codes used for common letters. PSK31 achieves a text speed of about 50 wpm, and uses software developed by G3PLX running on a PC with a soundcard. Peter Klein, KD7MW reports that by using the narrowest possible filters in his transmitter and receiver, the performance of PSK31 even without error-correction is certainly better than most modes, and has the added advantage for live QSOs that the performance degrades very gracefully as the signal drops. *Very* careful on-the-fly tuning was required to use PSK31 via AO-10 due to slight downlink frequency variations caused by the satellite itself. The downlink signal was observed to vary back and forth 25 Hz or more during an approximately 2-minute transmission. Peter found that if he used the PSK31 communications software and watched the phase circle carefully and hit the appropriate arrow key 3-5 times (Hz) when the phase indicator began to shift, he could keep the signal properly tuned. This variation was independent of the doppler shift. So the bad news is that while the transponder is stable enough for CW or SSB, it's not quite stable enough for the tuning requirements of PSK31. Groundstations must "ride the receive tone frequency", and if you stop to read what you're copying, you'll miss something. A couple of determined operators will be able to pull off a QSO on BPSK, but they will have to work for it. Anyone wishing to attempt a PSK31 contact with Peter via AO-10 are asked to contact him via email: kd7mw@amsat.org [Info via Peter Klein, KD7MW] * FEEDBACK/INPUT WELCOMED * =========================== Comments and input for SpaceNews should be directed to the editor (John, KD2BD) via any of the paths listed below: WWW : http://www.njin.net/~magliaco/ PACKET : KD2BD @ KS4HR.NJ.USA.NA INTERNET : kd2bd@amsat.org, magliaco@email.njin.net SATELLITE : AMSAT-OSCAR-16, KITSAT-OSCAR-25 <<=- SpaceNews: The first amateur newsletter read in space! -=>> <<=- Serving the planet (and beyond) since 1987 -=>> /EX