SB SAT @ AMSAT $ANS-153.01 PARROT REPEATER ON SUNSAT HR AMSAT NEWS SERVICE BULLETIN 153.01 FROM AMSAT HQ SILVER SPRING, MD JUN 3, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-153.01 Parrot Repeater to Operate on SUNSAT A Parrot repeater will soon be operating on the two meter band providing fun communications to Radio Amateurs and scholars throughout the world. The repeater will be incorporated in South Africa's first satellite, called SUNSAT, which is currently under construction. SUNSAT is a 60 kg, 45 by 45 by 62 cm micro satellite being designed, built and tested by twenty two Engineering Masters students at the Electronic Systems Laboratory in the Department of Electrical and Electronic Engineering at Stellenbosch University. Stellenbosch is the second oldest town in South Africa, not far from the Southern tip of the African Continent. It is about fifty kilometers East of Cape Town. The university has about 14000 students. The satellite is being built by students who have done all detail design and software. System level design was done by lecturers, some of whom studied at the Universities of Surrey, Stanford and MIT. It is therefore not strange that the satellite is very similar to the UoSATs built at the University of Surrey. Detailed design started in January 1992, led by Computer and Control System lecturers. SUNSAT was originally designed for a sun- synchronous-type orbit on the Ariane 4 HELIOS mission, which is ideal for the main imaging payload. When launch costs became prohibitive, alternatives were sought. NASA scientists have learned much about the Earth by detailed studies of the magnetic field and the gravitational field, and had arranged for the Danish OERSTED micro-satellite to be launched as a secondary payload on a USAF Delta II from Vandenberg Air Force Base on the P91-1 ARGOS mission in January 1996. NASA and Stellenbosch have now agreed to carry SUNSAT into the same orbit instead of a counterweight for OERSTED. In exchange for the launch, SUNSAT will carry a precision GPS receiver and a set of Laser retro-reflectors. These will enable NASA to study fine orbital perturbations for gravity field recovery, and for cross verification of GPS and NASA's laser tracking network. The orbit will be the same as OERSTED, namely polar, 400 by 840 km. The equatorial crossing will initially be at approximately 15:00, and drift an hour earlier every seventy days. During the initial stages of the design of SUNSAT, ideas were sought for what should be included in the satellite. Very optimistically, a two meter repeater was suggested as this would be the one item that nearly all amateurs would be able to operate. However, SUNSAT is a micro- satellite and to get space on a launch vehicle, weight and size must be restricted. So, there was no room for the large duplexer that is part of a two meter repeater. A Parrot repeater was then suggested. A Parrot repeater operates by digitizing audio sent to it on the uplink and then storing it in memory, of which SUNSAT has 64 Megabytes. When the operator on the ground releases the PTT, the digital record is converted back to audio and fed to the transmitter which is on the same frequency as the receiver. SUNSAT's Parrot repeater will sample audio at 8000 times per second. Data words will be 8 bit, and records will be restricted to five minutes each. The repeater will periodically announce that it is available for use. The voice system will also be used for transmitting messages which will be uploaded by the command team. [Thanks to Henry Chamberlain, ZS1AAZ, and Hans van de Groenendaal, ZS5AKV, for the information that went into this ANS bulletin item] /EX SB SAT @ AMSAT $ANS-153.02 AMSAT OPERATIONS NETS HR AMSAT NEWS SERVICE BULLETIN 153.02 FROM AMSAT HQ SILVER SPRING, MD JUN 3, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-153.02 New AMSAT Operations Net Schedule Announced To take full advantage of the current "good" phase on AO-13, Keith Pugh, W5IU, AMSAT VP of Operations, has announced the following AMSAT Operations Net Schedule. The primary downlink frequency for all Ops Nets will be 145.950 MHz. In case a QSO is in progress on that frequency at net time, 145.955 MHz will be used as an alternate. Net control for all of these nets will be Keith, W5IU; however, anyone is welcome to serve as an alternate. Reports on all phases of OSCAR operations are welcome. Guest speakers on special topics will be scheduled as availability permits. Day Date Time Coverage ___ __________ ____ _______________ Sun. 04 Jun. 1995 1000 ENA, SA, WEu, WAf Sat. 10 Jun. 1995 1100 NA, SA, WEu, WAf Sat. 17 Jun. 1995 1500 NA, WSA, NZ Field Day - 24-25 Jun. No Net Good Luck on the Birds Sat. 01 Jul. 1995 1430 NA, SA, NZ, EAus Sun. 09 Jul. 1995 1330 NA, WSA, NZ Sun. 16 Jul. 1995 0500 ENA, SA, WEu, Af, MidE Sun. 23 Jul. 1995 1230 NA, SA, NZ, EAus Sun. 30 Jul. 1995 1200 NA, WSA, NZ, JA, EAus Note: All times are in UTC; therefore, Sunday dates may actually be Saturday evening in USA. Times do not conflict with ZRO Tests. [Thanks to Keith Pugh, W5IU, for the information that went into this ANS Bulletin item] /EX SB SAT @ AMSAT $ANS-153.03 AO-13 ZRO TEST SCHEDULE HR AMSAT NEWS SERVICE BULLETIN 153.03 FROM AMSAT HQ SILVER SPRING, MD JUN 3, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-153.03 New AO-13 ZRO Test Schedule Announced The ZRO Memorial Technical Achievement Award Program, or just "ZRO Test", has a new schedule for June 1995 through July 1995, via AMSAT-OSCAR-13. This activity is a test of operating skill and equipment performance. During a typical ZRO run, a control station will send numeric code groups using CW at 10 words-per-minute. At the beginning of the run, uplink power from the control station is set to match the general beacon downlink strength. This is level "zero". The control operator will send and repeat a random five-digit number, then lower his uplink power by 3 dB (half power) and repeat the procedure with a new random number (level "1"). This will continue to a level 30 dB below the beacon (level "A"). A participating listener monitors the downlink signals until they can no longer copy the numbers. Those who can hear the beacon will qualify for the basic award by copying the code group heard at level "zero". The challenge is to improve home-station performance to a point where the lower-level downlink signals can be copied (levels 6 through A). To date, only one station (Darrel Emerson AA7FV) has successfully copied level "A". The following schedule of Mode "B" tests were chosen for convenient operating times and favorable squint angles. Due to the current orbit of AO-13, choices for this round of tests are limited. More tests will be scheduled for the next "season" of "Nadir" pointing. The tests can be heard on 145.840 MHz. Andy, WA5ZIB, will conduct all the tests. Mode "JL" tests are no longer possible due to the failure of AO-13's 70- cm transmitter. Day Date (UTC) Time Areas covered Saturday June 17, 1995 1600 UTC NA, Pacific Sunday July 2, 1995 1300 UTC NA, SA Saturday July 22, 1995 1345 UTC NA, Pacific Note that the dates and days are shown in "UTC". Any changes will be announced as soon as possible via the AMSAT HF and AO-13 Operations Nets. All listener reports, with date of test and numbers copied, should be sent to Andy MacAllister WA5ZIB, AMSAT VP. User Operations, 14714 Knights Way Drive, Houston, TX 77083-5640. A report will be returned verifying the level of accurate reception. An S.A.S.E. is appreciated, but not required. Information about the AMSAT Awards Program can be found on page 197 of the "Proceedings of the AMSAT-NA Tenth Space Symposium" (1992). This paper, covering all the AMSAT-NA awards including specifics on the ZRO Test, was reprinted on page 10 in the March/April 1993 issue of "The AMSAT Journal". The ZRO Test information provided in the article covers test procedures, means for obtaining certificates and gives some historical background about the program. Reprints of the article can be obtained for an S.A.S.E. to WA5ZIB at the address above. [Thanks to Andy MacAllister, WA5ZIB, for the information that went into this ANS Bulletin item.] /EX SB SAT @ AMSAT $ANS-153.04 CHECKSUM ISSUE CLARIFIED HR AMSAT NEWS SERVICE BULLETIN 153.04 FROM AMSAT HQ SILVER SPRING, MD JUN 3, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-153.04 Keplerian Checksum Issue Clarified. Ray Hoad, WA5QGD, AMSAT-NA Orbital Data Manager, reports that the USSPACECOM will go back to their old Keplerian element format with checksum included. Adam Johnson (NASA OIG BBS) told Ray that there still may be a change to their format in the future, however, such a change would not occur without ample notice. For now, and for the foreseeable future, their Keps will contain a checksum. Ray indicated that any changes to their format would most likely occur within the next 90 days. Unfortunately, Ray reports that this week's raw 2-line Keps obtained from USSPACECOM still had no checksum. So, he has once again computed the checksum for both the AMSAT and the NASA 2-line Keps, and has tested them with INSTANTRACK, QUIKTRAK, and WISP. Ray noted that all these programs readily accepted the "massaged" data. In addition, Ray has now written some software so that checksums can be easily added to raw Keplerian elements. Ray concluded his report by saying that, regardless of any possible changes in the raw data, all AMSAT-NA supplied Keplerian elements will continue to be distributed with a checksum. [Thanks to Ray Hoad, WA5QGD, for the information that went into this ANS Bulletin item.] /EX SB SAT @ AMSAT $ANS-153.05 WEEKLY OSCAR STATUS REPORTS HR AMSAT NEWS SERVICE BULLETIN 153.05 FROM AMSAT HQ SILVER SPRING, MD JUN 3, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-153.05 Weekly OSCAR Status Reports: 3-JUN-95 AO-13: Current Transponder Operating Schedule: *** AO-13 TRANSPONDER SCHEDULE *** 1995 May 22 - Jul 31 Mode-B : MA 0 to MA 70 | Omnis : MA 230 to MA 25 Mode-BS : MA 70 to MA 110 | Mode-S : MA 110 to MA 112 |<- S beacon only Mode-S : MA 112 to MA 135 |<- S transponder; B trsp. is OFF Mode-S : MA 135 to MA 140 |<- S beacon only Mode-BS : MA 140 to MA 180 | Alon/Alat 180/0 Mode-B : MA 180 to MA 256 | Move to attitude 225/0, Jul 31 Note: The Mode-B beacon is ON during the Mode-S transponder operations only. Please do NOT uplink to the B transponder during Mode S only, as it interferes with Mode-S operations. [G3RUH/DB2OS/VK5AGR] FO-20 and RS-15: Stefano Badessi, PA3FWP, reports hearing terrific signals in Europe from FO-20 when it is flying over America, but that few American Hams are using the transponder during this time. He invites those interested in some LEO DX to listen for him, or to propose a sked with him via RS-15 and/or FO-20. [PA3FWP @ AMSAT.ORG] The AMSAT NEWS Service (ANS) NEEDS YOUR HELP! The ANS is looking for volunteers to contribute weekly OSCAR status reports. If you have a favorite OSCAR which you work on a regular basis and would like to contribute to this weekly bulletin, please send your observations to WD0HHU at his CompuServe address of 70524,2272, on INTERNET at wd0hhu@amsat.org, or to his local packet BBS in the Denver, CO area, WD0HHU @ N0QCU. Also, if you find that the current set of orbital elements are not generating the correct AOS/LOS times at your QTH, PLEASE INCLUDE THAT INFORMATION AS WELL. The information you provide will be of value to all OSCAR enthusiasts. [For a vacationing WD0HHU, your Guest Editor for this week's ANS Bulletins was Keith Baker, KB1SF] /EX