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Re: [aprssig] PCsat long term planning



PCsat Operations to resume 20 Nov:

Now that we have a better appreciation for some of the mroe subtle PCsat
power budget factors, we will enable the PCsat digipeater again.  But
since we have 40% less power these days compared to launch (we were in
full sun) we will try to manage the power demand by some modifications to
the usage plan.

I have updated the user service agreement for PCsat to reflect the new
operating paradigm so that we can continue providing traveler, mobile and
HT communications support as our primary mission:

1) We are going back to NO DIGIPEATING via the COMMAND system W3ADO-1

2) User access is only authrized via the uplink path "VIA APRSAT"
   Thus, if PCsat is usable via that path, then you can use it.  If it is
   not usable, it will not digipeate via "APRSAT" and so no harm done...

3) Please no routine operations past local midnight (2300 preferred)...

4) Operations at night should only be IAW the primary mission of PCsat,
   to support Travelrers, Mobiles, HT's and special events... and demos

5) THE UHF 9600 baud recivers are off so both mobiles and HT's share the
   same VHF uplink.  Mobiles should do well at one packet per 5 mins or
   less.

6) If you are successful at the suggested rates, then cut back  your rate
   further until you average one sucess per pass that you operate.

7) No connects of any kind, please.

8) No routine unattended ops

If we can keep the user load under control so that we dont have any
minimum-power resets, then we will be able to oprate normally.  If user
demand is too high, the Satellite will reset in Eclipse and we all have to
wait a day for the command station to reload the operating parmamerters...

Bob, WB4APR


So we a On Sun, 18 Nov 2001, Bob Bruninga wrote:

> PCsat power budget and future plans:
>
> There are many cyclic effects on PCsat's power budget:
> 1) Daily Eclipse cycle
> 2) Annual phases of the sun and seasons
> 3) Precession of the orbit every 3.5 months (15 mins earlier per day)
> 4) Changing times of command station access relative to waking hours
> 5) Peak operating loads of users (evening Prime time)
> 6) Weekday versus weekend day users
>
> All of these cycles fell into phase in the negative direction this last
> week  and put PCsat in a power crunch causing resets every orbit during
> eclipse.
>
> We can fix some of this easily.  Remember that PCsat goes though the same
> day/night cycle as we all do but 15 times a day.  THus, if is daylight in
> your area during a pass, then PCsat is in the sun.  If it is dark, then
> PCsat is in eclipse.  If it is past midnight for you, then PCsat is more
> than half way through eclipse.  If it is before sunrise, then PCsat is in
> its worst case, near then end of an eclipse.
>
> Here is what we can do as a first step simple fix:
>
> 1) Ask for all operations to cease after 2300 local time eveerywhere
> (this reduces PCsat battery load during eclipse with little user effect)
>
> 2) Ask all users to divide their NIGHT time rates by 2 or 4 and or cease
> routine (non travelers) usage at night.
>
> The question is whether users will adopt these measures?  So far usage
> over the USA seems lighter than Europe.  Is it all more or less in
> accordance with the mission of PCsat?  Or is there still some routine
> types of usage that if minimized, might improve the user power budget
> substantially?
>
> de WB4APR@amsat.org, Bob
>
> PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
>
>
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de WB4APR@amsat.org, Bob

PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite  http://www.toad.net/~wclement/bruninga/mic-lite.html

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