PCSAT-1 and PCSAT2 DUAL-HOP OPPORTUNITY                      1 Dec 2005
-----------------------------------------------------------------------

PCSAT2 woke up Thursday morning, 1 Dec 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).  Actually the
same day that we accomplished a full recovery on PCSAT-1.

PCSAT2 volts immediately began to rise and after only a few orbits is
back to normal operating mode.  The user digipeater has been enabled
(145.825 uplink and 435.275 downlink.) and until 7 Dec, is using its
145.825 downlink for constellation operation with PCSAT-1.  Here are 
additional details on our plan to do some dual hop experiments:

1) We have added SGATE as an alias to PCSAT2 so that ANY over-the-
horizon PCSAT-1 originated packets (telemetry and beacons) 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 only be heard on the 
PCSAT-2 435.275 downlink.

3) After the SCHOOL CONTACT on Dec-02, PCSAT2 was switched from 435.275 
downlink 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.   

CAUTION:  Do not use PCSAT2 (on 145.825 downlink) if the crew is using
their ARISS radio for voice on 145.800!  Successsful packets tend to
block the crew's receiver...

4) THe PCSAT2 dowlink will shift back to 435.275 on 7 Dec 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) though
your own station may not be fast enough to see your own packet.

Transmit occassionally, NOT repeatedly.  If 60  people are trying, then 
you should transmit only 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