jul 21 2002
Bob Bruninga, WB4APR, har lmnat en del info om vad som hnder med PcSat just nu. Har ett utdrag:
Bob Bruninga WB4APR announced that PCSat has turned DIGI OFF and all 1200 baud TLM off.
Although PCsat has been perfectly usable in the afternoons into early evenings, the satellite is 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. That s all we would need to recover PCsat back into a positive power budget.
I will try this for the daytime passes over the USA this week (which will affect 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. What s 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. Dropping 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) and nothing else.
Mera info p hemsidan:
Klla: ANS 202