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Message started by Admin1 on Sep 3rd, 2021 at 8:39am

Title: OneWeb satellite constellation coverage animation
Post by Admin1 on Sep 3rd, 2021 at 8:39am
The Oneweb satellite constellation is not yet complete so whole world coverage is not yet possible.
The satellites are at 1200km height.



This picture above is a snapshot of an animation. 3 Sept 2021,  showing the coverages below each OneWeb satellite.  It is an unofficial plot based on published satellite TLEs so may be wrong regarding which satellites are active.

Link: https://satellitemap.space/

Best regards, Eric

Title: Re: OneWeb satellite constellation coverage animation
Post by Admin1 on Dec 7th, 2021 at 4:32pm
The circular coverages on the image above look wrong to me.  I think that each OneWeb satellite has 16 beams, arrayed north-south of each other, with each above/below the next, so the coverage of each satellite is essentially a square.  Each of the 16 beams is highly elongated east-west and narrow north-south.

Does anyone agree with this below ?

Ku band customer beams (down 12.75-13.25, up 14-14.5 GHz).
16 Ku band beams, wide east-west, narrow north-south.
Each satellite covers a square area of 48 deg x 48 deg,
Ku band antennas: each comprising a single row of 32 rx/tx patches. Length 1m.
Coverage Beamwidth (-3dB) = 48 deg x 3 deg
Area = 113 sq deg.   Equiv circ = 6 deg radius.

Gain = +24.3 dBi beam centre      +21.3 dBi beam edge.

Uplink G/T = 24.3 - 10log(325) = -1 dB/K (at beam centre)
Uplink G/T = 21.3 - 10log(325) = -4 dB/K (at -3dB beam edge)


* calculation revised 6 Jan 2022. Note sure what figures to use for antenna efficiency or uplink noise temperature. For time being I am assuming all patches are the same (~100% eff) and earth + LNA = 325 deg.

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