[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

PCsat sets NODIGI

PCsat users:

We just turned DIGI OFF and all 1200 baud TLM off.

Although PCsat has been perfectly usable in the afternoons into early
evenings, we are still running the batteries down on every eclipse.
So today I thought of one last low power mode I can try so we turned DIGI
and TELEMETRY OFF to see if we can make it through just ONE eclipse.
Thats all we would need to recover PCsat back into positive power budget.

I will try this for the daytime passes over the USA this week (which will
effect the evening passes over Europe)...

The lowest power mode of PCsat has been with all BULLETINS and all
DIGIpeating turned off.  Also we disable 9600 baud 1 minute telemetry as
well.   THus the only thing remaining was the once per minute single 1200
baud telemetry packet which is required to keep the heart-beat fail-safe
reset timer tickled.  Whats new, is that we realized that if we switched
the 1/min TLM to 9600 baud instead of 1200, we would further reduce the
minimum transmit duty cycle in our lowest power mode.  Thus halving our
transmit current drain.

Unfortunately, our TRANSMIT power is already less than 10% of the overall
bus power, so this move will only gain us about 5%, but worth trying...
Our minimum transmit average current drain (1 packet per minute) is
only about 16 ma out of the nominal 160 ma low power mode.  Droping this
in half saves us about 8 ma.  Who knows, maybe it is the straw that can
give new life to the camel?

Anyway, when PCsat is in this minimum mode, the ONLY thing you will hear
will be a once a minute half second noise burst... (9600 bd TLM)...
nothing else.

Sorry for the inconvenience.  If you were planning a PCsat demo this week,
let us know and we will turn it back on.

 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

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org