SB ALL @ AMSAT $ANS-233.01 AO-13 Testing and Operating HR AMSAT NEWS SERVICE BULLETIN 233.01 FROM WA2LQQ WARWICK, NY August 20, 1988 TO ALL RADIO AMATEURS BT While generally good operating conditions prevail on AO-13, tests of the RUDAK digipeater continue. Meanwhile, it is speculated terrestrial radar interference may be affecting Mode L AGC levels. Spacecraft controllers have modified the operating schedule slightly to allow more time for testing. Testing of the RUDAK continues with AMSAT-DL engineers looking at ways of circumventing a glitch which prevents uplinking operational software. The RUDAK unit installed on a water tower in Munich is being used to model the problem and test possible solutions. Testing will continue for an indeterminate period according to AMSAT-DL. Suspiciously high Mode L receiver AGC levels have led AO-13 engineers to a series of tests and measurements to determine the source. The prime candidate currently seems to be terrestrial radars operating in the 1.3 GHz range. The radar blanker on Mode L's 24 cm receiver is designed to suppress radar interference. But preliminary observations suggest the blanker might be getting pelted with more radar energy than it can handle leading to a pumped up AGC. Engineers plan to closely examine the Mode L downlink passband with a spectrum analyzer while AGC levels are high to see if there are any telltale signs of radar pulses in the downlink. These pulses are sufficiently short they cannot be heard on normal receivers with relatively narrow filters. But a spectrum analyzer can view the entire passband and look for pulses and pulse ensembles which would evidence radar being picked up by AO-13's 24 cm Mode L receiver. DB2OS says one datum which suggests the AGC is being pumped up by a terrestrial source, possibly radar, is that near perigee, when the Mode L receive antenna is looking into space, the AGC is unaffected. But at or near apogee, when the antennas are earth-looking, the AGC is being loaded even though there are few, if any, QSOs in the passband. Another possibility for the AGC activity is some sort of spread spectrum communication energy which would be very difficult to pin down. Meanwhile, controllers have implemented a modified operating schedule to facilitate testing. Here is the current AO-13 operating schedule. It will remain valid until September 21 and may be deviated from for engineering tests. Revised Operating Schedule: V3.1 19Aug88 +---------------------------------------------------------------+ | Mode | From | Thru | Remarks | Duration | | |(Inclus)| (Inclus)| | MA Minutes| |========|========|=========|==================================== | Off | MA 241 | MA 002 | Solar eclipse window | 18 48.3 | | Mode B | MA 003 | MA 099 | | 97 260.2 | | Mode L | MA 100 | MA 150 | Mode JL optional | 51 136.8 | | Mode B | MA 151 | MA 240 | | 90 241.4 | |--------+--------+---------+----------------------+------------+ | Mode S | | | Soon | | | RUDAK | | | Testing; ops pending | | +--------------------------------------------------+------------| The current attitude is approximately BLON=180, BLAT=0. On about 19 September, the attitude will be changed to BLON=210 and BLAT=+5 to respond to seasonal sun angle changes. Discussions among spacecraft planners and engineers suggest Mode S may be placed on line in a couple of weeks for initial tests. The preliminary discussions have the Mode S transponder on around apogee one day per week. Wednesday is being touted as an experimenter's day during which Mode S might be activated. Mode S, with its 70 cm uplink and 13 cm downlink, cannot be activated concurrent with Mode JL but can operate in conjunction with Mode B. The 13 cm beacon can be activated independent of the other transponders and beacons and will be turned on when the power budget allows and pointing angles permit its reception. /EX SB ALL @ AMSAT $ANS-233.02 AMSAT Space Ed Net To Debut HR AMSAT NEWS SERVICE BULLETIN 233.02 FROM WA2LQQ WARWICK, NY August 20, 1988 TO ALL RADIO AMATEURS BT The Space Education Network (SEN) project of AMSAT aims to provide timely information and tutorials on various aspects of space science and communications. This information will help improve individual skills in space communications and encourage a synergistic relationship among Radio Amateurs and those with an abiding interest in space sciences and technologies. The Space Education Network will begin on AO-13 on Saturday, September 3. The exact times and frequencies will be announced in next week's bulletins. Sessions on both Mode B and Mode L are planned. SEN bulletins will cover areas of current news in unmanned space exploration, the space shuttles and space stations and of course, the many amateur space projects underway. Each week will also include a bulletin covering milestones in the history of the Space Age. Tutorial sessions are being planned on topics such as beginning astronomy, space physics, balloon-borne amateur TV and amateur radio astronomy as well as more information on the internal workings of AO-13. AMSAT encourages all stations to check-in and enjoy the SEN. Your thoughts, ideas and assistance are solicited to make the SEN a successful and enjoyable experience obtained via satellite. Individual stations are also encouraged to provide gateway operations via local repeaters for the SEN. The bulletin material will begin on the hour and each session will provide time for questions. Gateway operation will be very helpful in bringing the SEN to a large number of amateurs not yet equipped for OSCAR. The SEN would also like to add SSTV to provide video with the bulletins and tutorials. If you are equipped for SSTV or have any other comments please let us hear from you. Contact K. O. Learner, II, K9PVW at P. O. Box 5006, Kokomo, IN 46904-5006 or by the packet network @KD9QB via W9ZRX. The SEN will meet Saturdays on both Mode B and Mode L when conditions permit. Times will be announced each week in these bulletins. Exact SEN schedules will vary with satellite availability. /EX SB ALL @ AMSAT $ANS-233.03 Surrey Announces New UoSATs HR AMSAT NEWS SERVICE BULLETIN 233.03 FROM WA2LQQ WARWICK, NY August 20, 1988 TO ALL RADIO AMATEURS BT Changes in the NASA/USAF launch manifest have resulted in the postponement of the UoSAT-C mission, originally scheduled for launch on NASA-DELTA in late 1988. However, Surrey has signed final agreements with Arianespace for the launch of two UoSAT satellites into an 800 km, polar, sun-synchronous orbit on Ariane with the SPOT-2 primary payload in early 1989. The Ariane launch opportunity - secured after long negotiations amongst UoSAT, AMSAT-NA and Arianespace -involves a total of seven payloads: SPOT-2 (a replacement for the SPOT-1 imaging satellite), UoSAT-D, UoSAT-E, and four AMSAT-NA Microsats. UoSAT-D and E will now take over the mission objectives of the postponed UoSAT-C mission to support: o Amateur Radio packet store-and-forward communications transponder, o studies of the orbital radiation environment, o in-orbit demonstration and evaluation of novel spacecraft technologies, o further development of low-cost CCD Earth imaging techniques. The UoSAT-D and E spacecraft, accompanied by the four AMSAT-NA Microsats, will be placed around a new Ariane structure - the Ariane Structure for Auxiliary Payloads (ASAP) - specially designed to provide small secondary payloads with inexpensive launch opportunities. The AMSAT-NA payloads include joint projects with Brazil AMSAT, AMSAT-LU and the Center for Aerospace Technology (CAST) at Weber State College, Utah. Due to mass limitations on the Ariane ASAP, the payloads originally intended for UoSAT-C have had to be split between two spacecraft (UoSAT-D & E). The two UoSAT spacecraft will be structurally identical, and have identical housekeeping subsystems, but will carry different payloads. UoSAT-D will carry an amateur radio digital store-and forward communications transponder operating in the amateur satellite service, and also investigate the effects of the space radiation environment on spacecraft components - funded by the University of Surrey, the Royal Aerospace Establishment (UK), AMSAT-UK and VITA (USA). UoSAT-E will support in orbit technology demonstration and CCD camera experiments. The primary payload on UoSAT-D will be the Packet Communications Experiment (PCE) which was originally to be carried on UoSAT-C. The PCE is an orbiting packet node with 4 Mbytes of message storage space and advances the work done on UoSAT-2 with the Digital Communications Experiment. The PCE system (hardware and software) is being developed under a contract from the Volunteers In Technical Assistance (VITA), which hopes in the future to use store-and-forward communications as a link with development workers in remote areas. The flight of the PCE on UoSAT-D and its use by radio amateurs will be funded by the University of Surrey and AMSAT-UK. ALL amateur radio stations with appropriate equipment will have open access to the PCE via AX.25 packet radio. The UoSAT-D PCE will use 9600 bits/sec, frequency-shift-keyed (FSK) uplinks and downlinks. These channels will be compatible with the K9NG-TAPR modem and a new G3RUH modem. The spacecraft will operate in Mode J with the uplink in the 2m band and a downlink in the 70cm band. RF communications links should be good enough to provide a consistent service to groundstations with modest non-steered antennas. An experimental high-power downlink mode for very-small groundstations will also be included. /EX SB ALL @ AMSAT $ANS-233.04 Path Clears For Shuttle Launch HR AMSAT NEWS SERVICE BULLETIN 233.04 FROM WA2LQQ WARWICK, NY August 20, 1988 TO ALL RADIO AMATEURS BT The U.S. space shuttle program seems to be heading for a launch date decision in the next few days. The last of the critical tests and repairs have been made NASA seems confident it can at last resume launches within about a month. A critical ground test of the main engines was successfully completed August 10. This past week, on August 18, a ground test of a solid rocket booster (SRB), into which more than a dozen flaws were introduced, proved successful. Elated NASA officials hailed the test and said preliminary indications were it was a complete success. Final results should be available in two weeks after engineers disassemble the rocket case and closely inspect it. They will be checking to see if the modifications installed prevented hot gasses from escaping through the backup seal even though intentional flaws had been introduced in various critical zones. Meanwhile, technicians have apparently successfully repaired a gas leak in the shuttle's Orbital Maneuvering System (OMS) pod. By cutting two access panels through the aluminum bulkhead, a technician was able to install a clamshell-like fixture over a coupling in a nitrogen tetroxide line. The coupling was inaccessible prior to cutting the access panels and NASA feared a major delay of two months would result if the normal repair procedure had been followed. That would have entailed pulling the shuttle off the launch pad and taking it back to the assembly building for repair, a process that could have cost up to 8 weeks. But with the fixture enclosing the leaky pipe, it will now be pressurized with a sealing compound and then tested to see if the leak has been sealed. Engineers are confident the repair will be found effective. NASA is now looking at launching Discovery in early October although it says it still has a shot at late September. /EX SB ALL @ AMSAT $ANS-233.05 Hints For AO-13 RTTY Reception HR AMSAT NEWS SERVICE BULLETIN 233.05 FROM WA2LQQ WARWICK, NY August 20, 1988 TO ALL RADIO AMATEURS BT Copying AO-13's RTTY telemetry is easy and quite popular thanks to the many electronic data boxes now on the market which handle packet, RTTY and CW among their functions. But some AO-13 observers are having difficulty configuring their devices for proper AO-13 RTTY reception. John, WA3WBU, offers the following guidance on the subject. The biggest problem stems from using the newer multi-mode digital interfaces. Some of these radios have a "vhf" and "hf" mode. Although it seems logical to place them in the "vhf" mode for the AO-13 RTTY beacon, it is not the correct setting. On most of these units, placing them in the "vhf" mode (packet or RTTY) enables the 1000 Hz shift tone pair. But AO-13's RTTY uses the standard 170 Hz RTTY. Most of the current units have a 200 Hz or "hf" mode. This is the mode to be selected when copying RTTY on the satellite. The slight difference between 200 & 170 Hz shift will not effect operation. So basically the setup procedure should be: 1. RTTY mode 2. 60 wpm or 45 baud 3. HF mode enable (200 Hz shift) 4. Unshift-on-Space OFF or disabled 5. Receiver in upper sideband Basically the unit, whatever your using, should be set up exactly as it would to copy RTTY on the HF bands, John says. /EX SB ALL @ AMSAT $ANS-233.06 Cosmonauts Prepare For Mission HR AMSAT NEWS SERVICE BULLETIN 233.06 FROM WA2LQQ WARWICK, NY August 20, 1988 (Story by KC2ZF) Four Soviet cosmonauts, along with two Afghan counterparts, have left Star City enroute to the Soviet Cosmodrome at Baikonur in Soviet Central Asia in preparation for a joint mission set for lift-off August 29. Final preparations are underway readying their Soyuz TM-6 spacecraft and the actual flight crew of two Soviets and an Afghan guest cosmonaut have yet to be announced. The mission to the space station Mir is expected to last 10 days. Listeners may expect transmissions on 121.750 MHz (FM) from Soyuz during its 48-50 hour ascent prior to rendezvous and docking with the orbiting laboratory. Of course, the usual downlink frequency of 143.625 from Mir will be in evidence during the mission. /EX SB ALL @ AMSAT $ANS-233.07 Short Bursts HR AMSAT NEWS SERVICE BULLETIN 233.07 FROM WA2LQQ WARWICK, NY August 20, 1988 TO ALL RADIO AMATEURS BT Roy, W0SL, says he's updated his popular ORBITS II and ORBITS III tracking program to be compatible with the Kansas City Tracker. There is now a version which uses the math co-processor for higher processing speed, W0SL adds. These programs by W0SL are available from the AMSAT Software Exchange. G3IOR reports UoSAT OSCAR 9's HF beacon is being heard again after a long absence. UA3CR spent some time in the UK discussing packet radio BBS operation. Upon his return home, he promptly placed PBBS UA3CR-2 on the air on 14.099 MHz. It serves as a BBS/Mailbox with VHF links into the Moscow area. The BBS may at times operate under an alternate callsign RA3APR. Here is the FO-12 operating schedule. Mode From (UTC) ---------------- JD Aug 20 0415 DI 21 0523 JD 25 0348 DI 26 0457 JD 27 0606 D 28 0511 JA 30 0120 D Aug 31 0228 JD = Digital mode JA = Analog mode D = All systems off DI = Systems off except CPU and memory The transponders will be off at other times. The actual operating schedule may change due to unexpected situations such as variations in available power. Mode JA Beacon: 435.795 MHz. Mode JD Beacon: 435.910 MHz. /EX