
SB SAT @ AMSAT   $ANS-014.01
G3IOR RS-15 KEPS                  

HR AMSAT NEWS SERVICE BULLETIN 014.01 FROM AMSAT HQ
SILVER SPRING, MD JANUARY 14, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-014.01

G3IOR Keplerian Elements For RS-15 

As you many have noted, none of the objects from the RS-15 launch provide a
very good match to the actual passes of RS-15 when those Keplerian element
sets emanating from NORAD/NASA are placed in your computer.

Pat (G3IOR) has been "tweaking" experimentally-derived element sets for
RS-15 since it was launched.  Here is his latest, which is accurate within
about 15 seconds as of 15 January:

RS-15
1 99915U          94360.16222500  .00000000  00000-0  13414-4 0    26
2 99915  64.8310 174.9040 0173420 233.4418   0.0000 11.27498800    13

>From his QTH in Norwich, Norfolk, England (JO02PP), Pat has so far managed
to work Nebraska, Arizona, New Mexico, Texas, Oregon and California to
date, and even Dennis N6DD at 34.038N 117.797W in a mutual one minute
window horizon grazer.  He reports ery little activity from Asia and Africa
so far, but lots of Europeans.

[The AMSAT News Service would like to thank G3IOR and W2RS for this bulletin
 item.]

/EX
SB SAT @ AMSAT   $ANS-014.02
SUNSAT SET FOR JAN '96 LAUNCH

HR AMSAT NEWS SERVICE BULLETIN 014.02 FROM AMSAT HQ
SILVER SPRING, MD JANUARY 14, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-014.02

SUNSAT: A Micro Satellite Under Construction In South Africa

SUNSAT is a 60kg, 45 by 45 by 62 cm micro satellite being designed, built
and tested by twenty Two M.Eng. students at the Electronic Systems Labor-
atory in the  Department of Electrical and Electronic Engineering at
Stellenbosch University.

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.
However, when launch costs became prohibitive, alternatives were sought.

NASA scientists have learned a great deal about the earth by detailed
studies of the magnetic field and the gravitational field, and have arranged
for the Danish Oersted microsatellite 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
approximately 15:00 UTC, and drift an hour earlier every seventy days.

SUNSAT is a complex microsatellite.  Its developers expect they will not
have time and manpower to utilize all its possibilities, and hope that other
amateurs and universities will become interested in using it once it is
fully commissioned.  Since this is their first satellite, they recognize
this may take many months to get right.

The Amateur Radio communications payload comprises a packet radio service,
a 2M band "parrot" speech transponder, and a Mode-S transponder.

The use of an imaging system necessitates attitude stabilization.  Coarse
attitude stabilization will be by a gravity gradient boom and by mag-
netorqueing and is improved by small reaction wheels during imaging.
Continuous spacecraft attitude sensing is provided by magnetometers, sun
sensors, visible wavelength horizon sensors, and a star sensor provide 1
miliradian accuracy when imaging from the sun-synchronous orbit.  The
average power of 25W enables images of South Africa and elsewhere to be
taken on a daily basis for real time downlinking.

Availability of excellent linear Silicon CCD sensors able to operate in the
visual and near-IR band led to a 3-color sensor system with bands similar to
SPOT 4 and LANDSAT 6.  These permit "biomass" production monitoring, which
is of continuing interest in a "water-short" country like South Africa, for
example.  A linear CCD sensor with 3456 pixels of 10.7 microns spacing was
also chosen.  The optical assembly is mounted in a tube which can be rotated
forward or rearward for stereo images.

The communications payload provides duplicated synthesized transmitters and
receivers for the 2M and 70CM Amateur Radio bands and nearby frequencies.

A 23CM receiver will operate as a fast uplink, or be coupled to the
S-band downlink transmitter to provide a straight-through transponder.

The high resolution data will be transmitted in real time via the S-Band
downlink to reception stations at Stellenbosch and Johannesburg.  Small-
area images stored in the RAM disk can be down-linked at much lower rates.
For example, a 40 kbyte image covering a 4 km x 4 km area can be downloaded
at 9600 baud in about 100 seconds.  The SUNSAT team plans to be able to
supply such images on request to amateurs once the satellite is fully
operational.

At 800 KM altitude, a 5 deg elevation footprint has a diameter of 5,080 KM
and which spans 45 deg in longitude.  Radio range varies from 800 to 2,800
KM compared to the geostationary range of 36,000 KM.

Data communication with 10 watts or lower powered transmitters and a dipole
antennas is practical, permitting data interchange with low cost terrestrial
transceivers.  Since large quantities of data can be stored in the sat-
llite, global data transfer is possible.  AX25 data protocols will be used
to ensure error-free operation.

The 5 Watt EIRP S-band downlink will produce a 14.4 dB S/N ratio in a 40
MHz bandwidth at 2000 KM slant range for a 4.5 m diameter parabolic dish that
has a 100 degree Kelvin receiving station which is current what is being
planned for Stellenbosch.  By adding an L-band receiver and appropriate
switching, a transponder capable of 1 MByte/s with 2M diameter ground
stations can be implemented.  Application of the system for Amateur Radio
gateway service is possible.

The Amateur Radio payload definition was approved at the SA-AMSAT Spacecon
91 Conference.  Store and forward digital packet radio will be provided,
including 1200 baud AFSK for compatibility with terrestrial equipment common
in South Africa.  To provide sufficient uplink channels, one of the 2M
band receivers has four IF sections displaced in 25 kHz steps, and connected
to 1200 baud modems.  Three 9600 baud modems compatible with the G3RUH
standard are carried, and can be switched to various receivers and trans-
mitters.  Both the 2M up/down and 2M up/70CM down options will be included,
together with full bulletin board facilities.  The AMSAT Pacsat Standard
Protocols can be supported.

The 2M and 70CM downlinks can be switched to 10 Watts output, producing a
0.5 uV  signal (50 Ohm) at 435 MHz and  1.5 uV signal at 145 MHz with 0dBi
receive antenna at full range.  This power level will be used over critical
areas to provide signal to noise ratios approaching 15dB for easy reception.
At other times the power will be reduced.

A 2M "parrot" mode repeater is intended especially for Novice category users
(under the age of 16). Up-linked speech will be digitally stored and re-
transmitted on the same  frequency.  Novice school users will thus hear the
re-transmission and know that they are getting through.  The need to learn
and apply operating protocols will definitely be experienced!

Stay tuned to the AMSAT News Service (ANS) bulletins as more information
about SUNSAT will published as the launch date of January '96 approaches
for SUNSAT.

[The AMSAT News Service would like to thank Henry Chamberlain (ZS1AAZ) for
 this bulletin item.]

/EX
SB SAT @ AMSAT   $ANS-014.03
AMSAT OPS NET SCHEDULE

HR AMSAT NEWS SERVICE BULLETIN 014.03 FROM AMSAT HQ
SILVER SPRING, MD JANUARY 14, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-014.03

AMSAT Operations Net Schedule

To take full advantage of the upcoming "good" phase on AO-13, the
following AMSAT Operations Net Schedule will be in place.  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
________________________________________________________

Sat  21-Jan-95     19:00      NA, SA,  Eu, Af
Sat  28-JAN-95     23:00       NA, SA
Sun  05-FEB-95     02:00      NA, JA, NZ, EAus
Sat  11-FEB-95     18:00      NA, SA, WEu, Af
Sat  18-FEB-95     22:00      NA, SA

Note:  All times are in UTC; therefore, Sun. dates are actually Sat.
evening in USA.  Times do not conflict with ZRO Tests.

Thanks - Keith, W5IU, AMSAT VP of Operations

/EX
SB SAT @ AMSAT   $ANS-014.04
WEEKLY OSCAR STATUS REPORTS

HR AMSAT NEWS SERVICE BULLETIN 014.04 FROM AMSAT HQ
SILVER SPRING, MD JANUARY 14, 1995
TO ALL RADIO AMATEURS BT
BID: $ANS-014.04

Weekly OSCAR Status Reports: 14-JAN-95

AO-13: Current Transponder Operating Schedule:
The Mode Schedule from 19-DEC-94 until 20-FEB-95 will be:
Mode-B  : MA   0 to MA 100 |Omnis : MA 230 to MA  25
Mode-BS : MA 100 to MA 130 |
Mode-S  : MA 130 to MA 132 |<- S beacon only
Mode-S  : MA 132 to MA 155 |<- S transponder; B trsp. is OFF
Mode-S  : MA 155 to MA 160 |<- S beacon only
Mode-BS : MA 160 to MA 180 | Blon/Blat 180/0
Mode-B  : MA 180 to MA 256 | Move to attitude 230/0, Feb 20
[G3RUH/DB2OS/VK5AGR]

FO-20: FO-20 is in the analog mode permanently and thus those that enjoy
working a "non-digital" mode will like FO-20.  Many FO-20 users are
complaining that they are hearing themselves calling CQ on the downlink
but there are no stations responding.  [KF0QS]

MIR: The cosmonauts aboard MIR ask that those who use its packet BBS to
please delete their mail messages after reading them.  They have a limited
memory TNC and with all the use it has been getting lately, the 22 KBytes
fills up quickly! Also remember that the MIR PBBS can only accept one con-
nection at a time.  All other stations must STOP calling the MIR PBBS while 
a station is actively using the MIR PBBS.  Calling the Mir PBBS, while some-
one else is logged in and trying to transfer data is poor operating practice 
and could be considered "intentional interference".  [WF1F & KD2DB]

KO-25: WA4SCA reports that the KITSAT-OSCAR-25 Bulletin Board System is 
open and working.  [WA4SCA]

The AMSAT NEWS Service (ANS) NEEDS YOUR HELP! The ANS 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
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.

/EX


