Programmer 7500

home *** CD-ROM | disk | FTP | other *** search

/ Programmer 7500 / MAX_PROGRAMMERS.iso / PROGRAMS / UTILS / HAMRADIO / AMSAT8_1.ZIP / AMSAT8-1.TXT

Wrap

Text File | 1988-08-01 | 24.9 KB | 493 lines

********** <<< AMSAT INFO from W0RPK BBS >>> ********** ... down-loaded directly by N4XY on 880801 (AUG 1st 1988). ------------------------------------------------------------------------------- Initial AO-13 Reports Positive HR AMSAT NEWS SERVICE BULLETIN 212.01 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT With a week's experience operating the new AMSAT OSCAR 13, new insights into the satellite are now emerging. The satellite officially continues in the engineering evaluation and "fine tuning" phase prior to being declared fully operational. Nevertheless, a large number of satellite users, newcomers and veterans alike are appearing on the satellite. The attitude of AO-13 is now said to be at or close to the target (BLON=180; BLAT=0). There have been no further magnetorquing sessions of any length around perigee for the last several days. While it is asserted the objective attitude has been attained, there is, however, some fragmentary evidence to the contrary. Mode L performance, for example, appears in some reports to be below specification. This could be due in part to satellite antenna off-pointing. Mode B operations, begun on July 22, continue apace with excellent results generally reported. Actual Mode B link performance seems to compare favorably with the published values suggesting 21.5 dBW EIRP (141 W EIRP) is sufficient for an average 10 dB signal-to-noise ratio downlink. Experience suggests a dB or so more uplink power may be required when the Mode B transponder is heavily loaded as it has been in recent days. Nevertheless, after the chaos of the initial operations on July 22, Mode B operations have been excellent. Mode J operations began July 24. Observations suggest this mode too meets or exceeds expectations. The recommended uplink power of 25 dBW (316 W EIRP) evidently is being exceeded by many users unfortunately. Downlink signals approaching 20 dB above the transponder noise floor were common suggesting QRO users are not hearing terribly well. AO-13 Mode J users should employ only sufficient power to equal the General Beacon at 435.651 MHz. Under normal conditions, that should require only about 20 watts to the feed of a 12 dBic antenna. The 50 kHz of Mode J sub-band has been chock-a-block with signals suggesting a high level of interest and satisfaction with its performance. Mode L operation, which also began July 24, has a way to go, however, to attain expectations. An analysis of Mode L performance is being made but there is no suspicion whatsoever of a transponder failure. Indeed, the fact that such potent signals are being heard from the J sub-band of the L transponder gives the L-transponder transmitter itself a clean bill of health. It's working great. The question is why are Mode L uplink signals not generating the anticipated downlink signal strengths? Reports from around the U.S. suggest Mode L downlinks are at least 10 dB less than expected. It may be, AMSAT officials said, that the reason Mode J signals are so strong and Mode L uplink signals don't currently compare is attributable to the difference in the uplink antenna beam widths. The 24 cm receive antenna has a much narrower beamwidth commensurate with its higher gain, they said. If one assumes some off-pointing, that would account for the difference in J and L uplink performance. (An analysis follows in another bulletin) In general, then, AO-13 appears to be performing very well and, with the exception of the open questions about current Mode L performance, providing excellent service even as the engineers complete their final check out procedures and prepare to commit the spacecraft to full operational status in a week or two. ............................................................................... AO-13 Ops Planners Give Sked HR AMSAT NEWS SERVICE BULLETIN 212.02 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT AMSAT OSCAR 13 continues under engineering jurisdiction and has not yet been officially released for full operations. This, despite the commencement of initial operations on July 22. Spacecraft controllers and engineers will be meeting in Marburg, West Germany this coming week to evaluate spacecraft systems performance to date and to plan general operations for the near-term and mid-term future. A new interim operating schedule has been announced as follows: Mode From Thru Duration MA Minutes ================================================================ Off MA 224 MA 31 64 171.7 Mode B MA 32 MA 99 68 182.4 Mode JL MA 100 MA 180 81 217.3 Mode B MA 181 MA 223 43 115.3 Mode S (Mode-S operations will commence when sun angles permit; likely in September RUDAK Concurrent with Mode L According to AMSAT-DL, this schedule may be changed without prior notice due to engineering tests and measurements. Part of the purpose of the command station meeting in Marburg is to map out a new schedule for transponder operations which accounts for all the various factors such as sun angles, seasonal changes, antenna beam widths, etc. Also being considered will be the content of the PSK, RTTY and CW bulletins. Preliminary notions are to include at least MA, Bahn coordinates and Keplerian elements as well as the operating schedules in the PSK and RTTY bulletins. ............................................................................... AO-13/L Performance Deficit? HR AMSAT NEWS SERVICE BULLETIN 212.03 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT As good as operations on Modes B and J have been, in contrast, Mode L has not yet achieved expectations. It now is clear part of the answer resides in the Mode L performance specifications themselves. The specifications were changed by AMSAT-DL this Spring after AMSAT-NA had published what it thought were the final specs. Consequently, uplink power requirements are raised by 3.8 dB. AMSAT-NA had previously (1986) been provided a set of transponder specs by AMSAT-DL. These specs set Mode L recommended uplinks at 25 dBW (316 W EIRP) and were confirmed to AMSAT-NA in January 1988. Now, however, the most recent edition of the AMSAT-DL Journal says the recommended uplink is actually 28.8 dBW (757 W EIRP), an increase of 3.8 dB on the uplink requirements. But this spec change in and of itself does not fully account for what has been generally acknowledged in the U.S. to be at least a 10 dB performance deficit in Mode L. Where is the missing 6 dB? Is there a missing 6 dB at all, or is it a mirage? There is conflicting evidence on this issue. For example, G3RUH claims 2 watts to a 15 dBi antenna (18 dBW; 63 W EIRP) produced a usable CW return. If one assumes G3RUH's good ears means 18 dBW produced a 0.5 dB signal-to-noise ratio, then a 28.8 dBW uplink should produce a 11.3 dB signal-to-noise ratio and the new AMSAT-DL Mode L spec (28.8 dBW for 10 dB S/N) is more than validated. Thus there is no missing 6 dB. Furthermore, DL9GU has been running about 44 dBW to produce about a peak 20 dB SSB signal-to-noise ratio. According to the AMSAT-DL specs it should require 48.8 dBW for a 20 dB peak and 10 dB average signal-to-noise ratio. Thus, DL9GU's results also tend to argue there is no missing 6 dB. But observers in the U.S. tell a different story. The consensus here seems to be performance is down at least 10 dB from expectations. Discounting the approximate 4 dB DL-specsmanship glitch, that still leaves at least 6 dB missing. Careful Mode L tests made in the U.S. July 30 show a 10 dB signal-to-noise ratio (in 2.4 kHz) required an uplink of 38 dBW. That's 9.2 dB poorer than even the revised DL Mode L specs. This and related evidence (such as the fine performance of the J sub-band) seem to suggest AO-13 antenna pointing is at the heart of the mystery. To wit, stations looking west to the satellite report results approximate expectations (e.g. G3RUH, DL9GU). Stations looking east report a distinct performance deficit of not less than 6 dB. With a 49 degree 3 dB beamwidth on the 24 cm uplink and a 67 degree 3 dB beamwidth on the 70 cm downlink, Mode L off-pointing penalties can accumulate quickly. Off-pointing by 25 degrees, for example, could cost 4 to 5 dB. The fact that Mode L currently straddles apogee asymmetrically could be another clue as to what's going on AMSAT officials said. Clearly more time is required for assessing Mode L. The next week will allow U.S. users their first good look at Mode L in the Western sky. Careful analysis of the pointing over the next few days and even re-timing the Mode L operating period may affect the results significantly. It may be then that U.S. Mode L users can draw their own conclusions regarding Mode L link performance and determine if, in fact, there really is a 6 dB gap or not. ................................................................................ AO-13 Frequencies Recalibrated HR AMSAT NEWS SERVICE BULLETIN 212.04 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT The past week of operating AO-13 has provided a number of surprises. Among these surprises are discrepancies in the actual transponder frequencies compared to those previously announced. The discrepancies from the AMSAT-DL tables vary from 2 to 21 kHz. These are now updated based on actual measurements as follows: For Mode B, the sum of uplink and downlink frequencies equals a constant 581.398 MHz such that at Mode B mid-band, 145.890, the required uplink is 435.508 MHz. This uplink frequency is 3 kHz higher than previously announced. For Mode J, the sum of uplink and downlink frequencies equals a constant 580.413 MHz such that at Mode J mid-band, 435.965, the required uplink is 144.448 MHz. This uplink frequency is 2 kHz lower than previously announced. For Mode L, the sum of uplink and downlink frequencies equals a constant 1705.356 MHz such that at Mode L mid-band, 435.860, the required uplink is 1269.496 MHz. This uplink frequency is 21 kHz higher than previously announced. A correlation between J and L uplinks and the JL downlink has now been confirmed. The JL downlink sub-band center is 435.965 MHz. The corresponding L uplink is 1269.391 MHz. The corresponding J uplink is 144.448 MHz. Thus, stations transmitting on 1269.391 and 144.448 MHz should appear on the same downlink frequency in the absence of Doppler shift. When making frequency measurements, careful attention must be paid to Doppler shift. All beacon frequencies appear to be very close to the previously announced values; to within a kilohertz. Additional surprises have come in the form of the telemetry. It had been thought, based on the PSK telemetry frames, that on Mode B, the 70 cm omni and the 2 meter high gain array was being employed. As it now develops, the binary status bits for these functions were recently changed but that information remains esoteric. While it was reasonably well-known the spin rate values yielded by the telemetry were spurious, the antenna configuration status bit changes are new and unheralded. ................................................................................ AMSAT Pioneers New Microsats HR AMSAT NEWS SERVICE BULLETIN 212.05 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT A consortium of Amateur Radio groups and a Utah college have teamed to construct and launch a new class of ultra-compact "microsatellites". They are so small they can be launched on virtually any launcher. Three AMSAT organizations, AMSAT-NA, AMSAT-LU and BRAMSAT (Brazil AMSAT) have teamed with the Center For Aerospace Technology (CAST) at Weber State College, Ogden, Utah to produce four satellites. TAPR is providing initial financial support and ARRL is assisting with design and construction. Each satellite consists of a bus of common design which carries a mission-specific payload. AMSAT-NA and AMSAT-LU payloads are packet radio transponders (PACSATs). BRAMSAT's payload is a voice synthesizer and the CAST payload is an earth-looking, low-resolution CCD camera. The most unique characteristic of each satellite is its volume and mass. Only 23 cm (9 inches) on a side, each cubical spacecraft weighs less than 10 kg (22 lbs). The small mass and volume make it feasible to launch these spacecraft inexpensively. And microsats can fit where larger ones cannot so many more near-term launch opportunities are available. Microsats pioneer a new class of payload analogous to NASA's Shuttle Getaway Special cannister (GAS can) only smaller. AMSAT has pioneered small satellites for nearly 20 years with roles in OSCARs 5 though 13. A PACSAT is a packet radio store & forward communications satellite which can blanket every inch of the earth up to eight times per day. Two PACSATs will be built: One each for AMSAT-NA and AMSAT Argentina. AMSAT Argentina had undertaken a satellite project of its own beginning in early 1988 but decided to collaborate with AMSAT-NA on the PACSAT project instead. "We thought it would be most efficient to join with our colleagues from AMSAT-NA in the development of our satellite project," said AMSAT Argentina President Carlos Huertas, LU4ENQ. "We have found a way to incorporate many of our own ideas in the basic PACSAT design," Huertas said. Arturo Carou, LU1AHC, says "The satellite will be jointly constructed but financed by Argentine sources and licensed in Argentina. When placed in operation, LU-SAT will be commanded from Argentina but will be available for non-profit use by Radio Amateurs worldwide." BRAMSAT's Project DOVE (Digital Orbiting Voice Encoder) aims to "Be the first satellite specifically designed to transmit spoken messages that implicitly promote peace between the nations" says Brazil AMSAT President Dr. Junior DeCastro, PY2BJO. Project DOVE's primary function is to make direct access to satellite communication available to the "average man". It will produce signals which can be heard on inexpensive VHF scanner type radios -- the type commonly used to monitor police bands. Its implicit message of peaceful use of space will flow from an explicit space education mission. "It will not become a propaganda machine for anyone," PY2BJO says. "BRAMSAT will have the voice synthesizer programmed for various languages to interest students in developing engineering skills...the kind needed to build devices like Project DOVE," DeCastro adds. According to the mission plan revealed by PY2BJO, DOVE will transmit various telemetry parameters measured by its many sensors to provide a rich source of data on satellite in-orbit behavior. These data will be easily accessed by the "common man" because they will be transmitted in synthesized speech requiring no special receiving equipment; simply a VHF radio, a pad of paper and a pencil. PY2BJO emphasized "This mission has immense educational value for anyone equipped with a simple VHF scanner. It's a window to space for students and scientists in many areas of scientific research seeking easy, reliable access to such data." "The success of UoSAT OSCAR 11's Digitalker relaying SKITREK position data to perhaps 250,000 students and teachers equipped only with simple VHF radios has underscored our conviction there is great social value in Project DOVE," said Dr. DeCastro, PY2BJO. Construction of the four microsats has begun in a facility in Boulder, Colorado. Design activities are being carried out in Boulder and several other cities in the U.S., Argentina, Brazil and Canada. Several design reviews have already been completed. AMSAT-NA has contracted for a 1989 launch for these microsats. They will be launched by Arianespace into a 822 km sun-synchronous orbit inclined 98.7 degrees. The primary payload will be the French SPOT-II mission. A June, 1989 launch is planned. ................................................................................ ZRO-Test And SATFOX On AO-13 HR AMSAT NEWS SERVICE BULLETIN 212.06 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT With AO-13 now up and running, many users are looking forward to the return of the popular ZRO-Memorial Station Engineering Award, a component of AMSAT's Technical Achievement Awards Program. The ZRO-Tests were suspended when AO-10 lost its attitude control capability. The competition ran on AO-10 for nearly two years ending in 1986. The ZRO Test challenges individuals in an unusual way for an Amateur Radio competition. It requires the participant to copy CW signals at progressively lower levels and awards certificates of merit to those who demonstrate superior receive sensitivity of their stations. In this way it provides an explicit benchmark for the station's owner. He'll know in absolute terms how well he's hearing and in relative terms how well he stacks up to other satellite users. In the AO-10 Mode B ZRO Test, the level attained by most participants was a Z-6 meaning they could hear a test signal 18 dB weaker than the beacon; quite an achievement. Some poor chaps only could hear 3 dB below the beacon! They got a certificate and some free advice! The competition begins with a signal sent through the passband with a downlink amplitude equal to the beacon. That's the baseline or Z-0 level. Then the downlink is reduced by 3 dB to become the Z-1 level. A series of CW numbers is sent at about 10 wpm. The participant logs the numbers. Then the level is reduced by another 3 dB for the Z-2 level; 6 dB below the beacon. More CW numbers are sent at lower and lower levels until at Z-8, the signal is a faint 24 dB below the beacon. While a few have copied the Mode L test at -24 dB and thus earned a coveted Mode L Z-8 rating, only one station has thus far earned a Mode B Z-8 (W7ID). AMSAT says plans call for commencing the ZRO tests on AO-13 in early Autumn. The SATFOX Technical Achievement Award challenges the participant to locate a hidden "Fox" via satellite (AO-13) by measuring the Doppler shift of the emitter over a period of hours. Precision frequency measurements must be made and a complex analysis of the results is required. This competition is in the conceptual and development stage with mathematical and gaming studies under way now. A computer analysis program for participants is planned to reduce the computational burden. Nevertheless, the participant WILL be obliged to obtain and maintain high precision frequency standards and measurement tools and be knowledgeable in their use, That's where the skill comes in. First SATFOX experiments could be accomplished in late Autumn leading to first actual competition in early 1989. Other special events are planned for AO-13. According to AMSAT President WA2LQQ, "We plan to sponsor an array of challenging, non-disruptive operating and technical events. We'd like to see one major event every two months or so; more if justified." AMSAT membership will be required to participate in these events WA2LQQ pointed out. ................................................................................ UO-11 Doing Particle Wave Work HR AMSAT NEWS SERVICE BULLETIN 212.07 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT During July a number of particle/wave surveys have been carried out on UoSAT OSCAR 11. Specifically, these surveys have been conducted using the Multi-Channel Electron Spectrometer. The spectrometer detects electrons at eight nominal energy levels:8é╬╧W╟╩]E$τ╔¡∙Ü7ªL▐!ú200, 8100 and 13000 electron Volts (eV). Using control blocks, it is possible to initiate a survey at any point in the orbit. Each survey, which occupies 96k of memory, lasts for about 12 minutes. The surveys are being carried out to assist the Radio Society of Great Britain Propagation Studies Committee in analyzing the propagation of 50 MHz signals across the Atlantic. It is hoped that UO-11 will be able to detect precipitating electrons that may result in the enhanced propagation. The surveys are being carried out as the spacecraft passes over the North Atlantic at around 00:00 UTC. Results of these surveys will be published in the usual places according to the University of Surrey. ................................................................................ Launch Plan Includes PACSATs HR AMSAT NEWS SERVICE BULLETIN 212.08 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT Arianespace, the marketing and management arm of the European Space Agency, has announced its new launch manifest which includes a launch on which AMSAT will fly its new class of microsats. Launch Launch Launch Payload Satellites Date Vehicle ============================================================================= V-25 09/88 Ariane 3 G-Star III/Geostar R02 + SBS-5 V-26 10/88 Ariane 2 TDF-1 V-27 11/88 Ariane 4 Astra-1 + Skynet 4B V-28 12/88 Ariane 2 Intelsat V F15 V-29 01/89 Ariane 4 JC-Sat 1 + MOP-1 V-30 02/89 Ariane 2 Tele-X V-31 03/89 Ariane 4 Superbird A + DFS-1 V-32 04/89 Ariane 3 Olympus V-33 05/89 Ariane 4 TV-Sat 2 + Hipparchos V-34 06/89 Ariane 4 SPOT-2* V-35 09/89 Ariane 4 Intelsat VI F1 V-36 10/89 Ariane 4 Superbird B + Inmarsat 2 F1 V-37 11/89 Ariane 4 TDF-2 + DFS-2 *AMSAT plans to fly 4 microsats on this mission including projects sponsored by AMSAT-NA, AMSAT-LU, BRAMSAT and the Center for Aerospace Technology (CAST) at Weber State College, Ogden Utah. The AMSAT-NA and AMSAT-LU projects are PACSATs while BRAMSAT's and CAST's projects are aimed at a space education mission. ................................................................................ Short Bursts HR AMSAT NEWS SERVICE BULLETIN 212.09 FROM WA2LQQ WARWICK, NY July 30, 1988 TO ALL RADIO AMATEURS BT The AMSAT-UK/UoSAT Colloquium is taking place at the University of Surrey, Guildford, England, this weekend (29th to 31st). Many visitors from around the world are attending. Topics covered include all aspects of current and future amateur spacecraft. A report on the proceedings will appear next week. AMSAT has launched a major fund-raising campaign to re-vitalize its depleted treasury for important future projects. Generous donations to AMSAT are urgently needed now if AMSAT is to continue to serve your needs. Please respond positively to this appeal. You help is needed now. AMSAT now has two on-line BBS systems. The original run by W0RPK is located in Iowa and can be accessed at 515-961-3325. The newest BBS is run by WD0GML near St.Louis and can be accessed at 314-447-3003. There is no charge except telephone connect charges for this AMSAT service. Donations accepted at AMSAT HQ. Jeff Kelly, KT2K, operated what is claimed to be the first AO-13 gateway station on Mode B and Mode J on July 22 and July 24, respectively. Jeff linked the 220 MHz WA2VKH repeater in New Jersey through AO-13 with N2AAM at the controls. Numerous users using only 1 1/4m HTs QSO's through the new bird. Details in a feature story in ASR-181. Having difficulty copying AO-13's RTTY telemetry? Are you getting letters instead of numbers for the telemetry values? If you're using one of the electronic RTTY boxes, chances are you've got it set for "downshift on space". Since "figs shift" is not sent with each new number group in the AO-13 telemetry, you'll need to disable the "downshift on space" function of your RTTY box to get good copy of the number groups. Thanks to WA3WBU and W4FJ for this tip. Here is the current AO-10 operating schedule: Through July 31: Mode B MA 25 to MA 235 August 1 - August 15: Mode B MA 30 to MA 240 The satellite will be unavailable for use beginning August 16 because of predicted insufficient solar illumination and reduced battery charge. Here is the FO-12 operating schedule. Mode From (UTC) ---------------- DI Jul 31 1006 JA Aug 02 1020 D 03 1128 JA 06 0845 D 07 0751 JA 11 0617 D 12 0724 JA 13 0630 D 14 0536 JD Aug 18 0603 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. ================================================================================ ..... 73 de ED, N4XY