[amsat-bb] PCSAT-1 and PCSAT2 joint operations

["Robert Bruninga" <bruninga@xxxxxxxx>]

PCSAT2 should wake up Thursday morning in
good sun since the ISS just shifted its attitude
to XPOP (Xaxis Perpendicular to Orbit Plane).
This puts PCSAT2 fully facing the sun whenever
the ISS is in daylight.  (PC2 went to low-power
shut down a week ago on 23 Nov).

As soon as volts get above 14 volts we will 
re-activate the user digipeater (145.825 uplink
and 435.275 downlink.)  Here are additional
details:

1) We will add SGATE as an alias to PCSAT2 so 
that ANY over the horizon PCSAT-1 originated 
packets that are heard by PCSAT2 will be relayed.
(THey already have SGATE in them)...

2) Stations sending up through PCSAT-1 as a first
hop may get a 2nd hop through PCSAT2 if they
use any dual hop path (ARISS,ARISS; or WIDE2-2;
or PCSAT2,PCSAT-1; etc)  The second hop will
on ly be heard on the 435.275 downlink.

3) After the Airdrie  Alberta, Canada SCHOOL
CONTACT Fri Dec-02  at1759z, we may switch the 
PCSAT2 435.275 downlink down to 145.825 so that 
PCSAT2 and PCSAT-1 are identical systems both 
with uplinks and downlinks on 145.825 acting as a 
2-hop constellation both on 145.825.   

4) THe PCSAT2 dowlink will shift back to 435.275
to avoid any possible interference with the next
SCHOOL CONTACT with Sanderson,  TX, on 8 Dec
at 1730z.

Of course, the MORE that try the FEWER will be the
success rate.  So if you really dont know what you
are doing, PLEASE do not transmit and just watch.
YOUR station may be the one that SEES the dual
hop, so that should be a good reward too. 

THINK about the geometry. When PCSAT-1 is over the
horizon, but PCSAT2 is in view, then JUST LISTEN to
see if you hear any PCSAT-1 packets (transmitting
in this case will only jam yourself and everyone else
listening for the dual hops from PCSAT-1).

When one is over the ocean (no one using it) then
DONT transmit through the one in view (its just
jamming the channel we are all listening on).

Make your packet as SHORT as possible and use the 
shortest TXD for your TNC.  The PCSATs should 
respond with TXD's as low as 10 (100 ms).

 Transmit occassionally, NOT repeatedly.  If 60 
people are trying, then you should transmit on ly 
1/60th of the time.  Maybe once a minute or so. 

For details see the PCSAT2 web page:

http://www.ew.usna.edu/~bruninga/pcsat2.html

de WB4APR, Bob
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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