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FO-29 a beginners satellite!



Since FO-29 is now in digitalker mode, I am distributing this FAQ to the
space groups.

Since the previous posts on working the FO29 digitalker, I have been
asked several questions on how to hear the FO-29 digitalker.  What
follows is sort of an evolving FAQ. Feel free to distribute this
document.  KF4FDJ - May 2, 1999

The Japanese satellite, Fuji Oscar 29 (JAS-2), was launched on August
17, 1996, by H-II rocket No.4, along with the earth observation platform
satellite ADEOS, from Tanegashima Space Center of NASDA (National Space
Development Agency of Japan).  FO-29 is a small LEO (Low Earth Orbit),
Japanese owned satellite containing a digitalker, mode JA transponder,
and 1200/9600 baud packet capabilities.  The mode JA transponder
requires a SSB, or CW uplink signal on 2 meters, and transmits a
downlink SSB/CW signal on 70 centimeters.  Mode JA is a full duplex
mode.  You WILL hear your own downlink, which is crucial, in order to
compensate for doppler.  The satellite is also capable of mode JD,
(digital) at 1200/9600 baud.

Q    Is Fuji Oscar 29 always in digitalker mode, and what is it?
A    The digitalker on FO-29 is a digital loop announcement, which makes
the same announcement over and over. You will hear, "Ho- ho'kke'kyo,
this is JAS two."   The first part is the song of a bush warbler.  JARL
(Japanese Amateur Radio League), plans to cycle digitalker, mode JA, and
mode JD.  The digitalker message is subject to change.  Check
announcements on the BB for a mode schedule and other details.

Q    Do I need a multimode rig to hear the digitalker?
A    Since FO-29 transmits in FM mode while in digitalker, any FM or
multimode receiver capable of tuning the 70 cm ham band should be able
to detect the signal.

Q    Do I have to use a high gain antenna to hear the signal?
A    Digitalker operation dedicates most of the power budget of the
satellite to the FM transmitter, instead of spreading it across a mode
JA transponder. It is a very strong signal!  It is possible to hear the
satellite with a handheld scanner or transceiver, and a stock "rubber
ducky" antenna.  Most 70 cm base stations, or scanner listening posts,
with fixed antennas, should also be able to tune the signal.

Q    I've heard that a circularly polarized antenna is necessary to hear
FO-29.  Is this true?
A    While a circularly polarized antenna will help on mode JA, it is
not necessary with the digitalker.  It REALLY is possible to copy the
signal with a handheld device and a "rubber duck" antenna.  We have been
successful with a Yaesu FT-50R and a stock antenna.  You will need to
rotate the rig (and antenna) for the best orientation.  Experience shows
that horizontal polarization, with the axis of the antenna perpendicular
to the satellite gives the best reception.  Experiment!

Q    Where do I tune to hear the signal?
A    The transmit frequency is 435.910.  Of course, you will have to
compensate for doppler shift.  Just remember you will tune a little
higher in frequency as the satellite approaches your position, and a
little lower in frequency as it recedes.  You will always be tuning
higher in frequency when the satellite comes over the horizon.  Make
sure you have your radio set to tune small increments, as increases and
decreases in doppler are gradual, and linear.

Q    How long will I be able to hear the satellite during each pass?
A    Since FO-29 is a low earth orbit satellite, most passes will be
between 6 and 18 minutes in duration.  Timing is critical in working any
amateur satellite.

Q    What is the purpose of the digitalker?
A    The digitalker presents an easy opportunity for hams and non hams
to have their first taste of real time reception of signals from space. 
Use this opportunity to show a kid, or a terrestrial ham how easy it can
be to tune a satellite.  This opportunity is excellent for scout
meetings, monthly ham meetings, schools, or any place where nquisitive
persons congregate.  

Q    How will I know when the satellite is over my location?
A    You will need a program to generate predictions of when the
satellite is "visible" to you.  An excellent place to find downloadable
software for real time tracking of satellites, and other information on
the amateur satellite program in general, is:  

     http://www.amsat.org

Be sure to download the latest keplerian coordinates if you download a
tracking program.  Each prediction program needs these coordinates to
determine where the satellites are, and to help you determine when FO-29
will be over your horizon.  Another casual approach, is to use an online
prediction site, such as:

     http://acsprod1.acs.ncsu.edu/scripts/HamRadio/sattrack

This site will generate pass predictions for a selected satellite.

If you have any comments, additions, or modifications to this document,
please contact me directly.  We will attempt to post the latest version
whenever the satellite is toggled to digitalker mode.

73, Mike KF4FDJ

                                       __\/__ 
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 |  P  | |f|   * I.S. Professional ..... CNA .... Computer Consultant *
 |  3  |=|d|   *   AO10, AO27, FO20, FO29, RS13, RS15, MIR, E Layer   *
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