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Re: Re: [aprssig] PCsat Optical Comms Experiment



PCsat Optical Experiment:  NORAD Object # 26931 (do NOT use norad set #41,
it is in error).

> We will enable the LEDS at 9:35PM Eastern Standard Time (8:35 CST) on the
> night of 17 Nov as PCsat passes over New Orleans and turn them off as
> PCsat passes out of view 6 minutes later over Toronto. The pass will go
> across Louisiana, Miss, ALa, Tenn, Ky, Ohio, and Ontario.  PCsat will be
> in view of everyone in the USA at the time, but those viewers will be
> further away and looking through more atmosphere...

For what its worth, you can tell if we get the LED's successfully turned
on by watching the PCsat telemetry. If you see 00111101 the 7th bit being
a zero means they are ON.  The first two bits (00) will  probably be 00,
meaning we have the UHF receivers off to conserve power.

I will be commanding from a tent in the dark in the middle of nowhere on
a battery, so i hope I dont screw up...

User uplinks will be disabled to conserve power also... Please No connect
attempts either...

> Presumably it may be visible with binoculars and only rarely pointed in
> "your" direction... But if you do see it, it will be "red", like LED's.
>
> de WB4APR, Bob
>
> > PCsat has 80 standard red LEDs on the side facing the earth in the
> > horthern hemmisphere.  We can turn them on to see if anyone can see them.
> > This takes a good 50% of our power budget and so they can only be on for a
> > few minutes, so this will only be over the east coast and only one pass
> > which appears to be about 930 PM on Saturday night the 17th of Nov.
> >
> > This is not the optimum time relative to  power budget, but it is an
> > opportunity when more people will be watching.  When I get to work
> > tomorrow and have a new set of Keps, I will nail down the exact time and
> > path over the usa.  So this is only a heads up...
> >
> > We have not done a detailed analysis, but with 3 watts of DC power going
> > into the LEDs, some have estimated a magnitude 5 or 6 straight down
> > (barely visible with eyeball) and maybe a mag 8 off to the side
> > (binocluars).  ANy other estimates are welcome.  We have no pedigree on
> > the LEDS other than "standard red leds"...
> >
> > PCsat appears to be spinning at about 1/4 RPM (exact attitude unknown)
> > so for any given viewer, you will only see the narrow field of view (about
> > 30 degrees) occassionally (if at all), but someone somewhere should get a
> > straight shot at some time...
> >
> > We may cycle the LEDS on and off at about a few second rate to save
> > power, this is TBD.  Even if this test fails to be seen, we will conduct
> > the test again later in the month when the optimum power is available.
> > That orbit is one that occurs just after dark, and just after PCsat enters
> > eclipse.  At that point the batteries are fully charged and so we get
> > maximum power to the LEDS.

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