Re: [amsat-bb] commutating antennas (was Re: Canted S-band antennas on satellite)

[Franklin Antonio <antonio@xxxxxxxxxxxx>]

At 06:46 AM 5/3/2002, Bob Bruninga wrote:
>Neat idea!... but at near geo altitudes wouldnt it take about 24 sides
>for maximum gain?  I think from that altitude, then the earth is less than
>15 degrees across.  So for max gain, the antennas would need to have beam
>widths of only about 15 degrees and so then you would need 24 of them to
>cover one rotation of the bird.

At very high altitudes it has that difficulty.  However, at altitudes of a 
few thousand km, the numbers work out nicely.

>BUT, I guess if you made them FAN beams that are wide in the plane of
>rotation but only 15 degrees tall, then in fact, I guess you could do
>that quite easily with a 6 sided satellite and only loose about 6 dB
>from the maximum gain possible...

Yes, that optimization helps.

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