[amsat-bb] squint angles and P3D

[williamb@xxxxxxxxxxx (William B Magnusson)]

Hi Stacy (et al),

Thanks for the replies.

>The whole idea of 3-axis stabilization is to keep the antennas pointing at
>the sub-satellite point.  Thus, the squint angles should always be low and
>not worth calculating.

Yep ... that's what I'd read. The question was rather from the perspective
of a southern hemisphere station where we will probably see the perigee
passes where the satellite height will be low compared to apogee.

>Also, the antenna/transponder selection will be made such that the field of
>illumination by the antenna is appropriate for the satellite distance. 

That answers my question.... thanks Stacy.


>  
>	ArcTan(Subsat.pt.Dist/Satellite Height) = Squint Angle
>

Thank for the formula.


> Remember, though, that P3D will occasionally go into spin mode to dump the
>momentum wheel energy, etc.  During these times, squint angles can be
>calculated just as for AO-13.
>

Hadn't read that anywhere, thank you ....

Regards to all, Bill...vk3jt

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