[amsat-bb] Re: AO-51 0009z on or off?

Andrew Glasbrenner glasbrenner at mindspring.com
Sun Jul 25 14:08:38 PDT 2010

Alan Cresswell wrote:
> Hi drew,
> I notice that when AO-51 comes over ZL/VK after coming out of eclipse (about
> 5 minutes since eclipse) that after some use the transponder drops out and
> will not retrigger for 10 to 15 seconds.  This behavior continues right
> through to LOS.  I presume this is caused by the batteries still being only
> lightly re-charged and with use they drop below some cut-off level.  My
> question is to whether this is of concern and should usage in this part of
> the world be restricted for longer after eclipse.
> 73
> Alan
Your presumption is correct. The power management software watches both 
eclipse state from the panel voltages, and battery voltages. Things are 
currently arranged so that eclipse or battery voltage below a VERY 
conservative set point reduces downlink power to zero.  A similar thing 
happens when a command station turns 435.150 on along with the regular 
downlink. As the battery sags, or the spacecraft turns and panel outputs 
fluctuate sometimes both transmitters will shut off for a few seconds. 
Of course when this happens the battery quickly rebounds and they pop 
back on.

Thanks for asking, but it is perfectly fine to continue use when this 
happens. Especially with the case of ZL, there is plenty of open ocean 
with no use for things to finish charging up.

73, Drew KO4MA

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