Hacker Chronicles 2/HACKER2.BIN/1149.AMSATN.212

Text File | 1988-08-02 | 25KB | 488 lines

SB ALL    @ AMSAT  $ANS-212.01
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.

/EX
SB ALL    @ AMSAT  $ANS-212.02
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.

/EX
SB ALL    @ AMSAT  $ANS-212.03
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 there 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.

/EX
SB ALL    @ AMSAT  $ANS-212.04
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.

/EX
SB ALL    @ AMSAT  $ANS-212.05
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.

/EX
SB ALL    @ AMSAT  $ANS-212.06
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.

/EX
SB ALL    @ AMSAT  $ANS-212.07
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: 30, 300, 800, 1600, 3200, 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.

/EX
SB ALL    @ AMSAT  $ANS-212.08
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.

/EX
SB ALL    @ AMSAT  $ANS-212.09
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.

/EX