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<blockquote data-quote="Bobben" data-source="post: 24852" data-attributes="member: 176053">I am sure that Astra do NOT know where the sidelobes exist.&nbsp; It is extremely complex to calculate as the satellite has multi feeds illuminating the shaped antenna onboard the satellite.&nbsp; For a normal parabolic antenna it is more easy to calculate sidelobes but it will be wery complex for spin stabilised satellites like Astra 2D where no normal parabolic antenna is used and probably 10-15 feeds is directed to the reflector in order to shape the footprint. You will not find a absolute null somewhere or a clear defined sidelobe. The footprint consists of several small beams and a null of one beam could be on a sidelobe of another - as you can imagine it is wery complex.Astra do not need this information as the satellites mainlobe is whats supposed to give the official coverage aerea where Astra can provide high link availability (probably 99.998% if the right antenna size is used).&nbsp; Astra cant sell services based on sidelobe reception.</blockquote>

[QUOTE="Bobben, post: 24852, member: 176053"] I am sure that Astra do NOT know where the sidelobes exist. It is extremely complex to calculate as the satellite has multi feeds illuminating the shaped antenna onboard the satellite. For a normal parabolic antenna it is more easy to calculate sidelobes but it will be wery complex for spin stabilised satellites like Astra 2D where no normal parabolic antenna is used and probably 10-15 feeds is directed to the reflector in order to shape the footprint. You will not find a absolute null somewhere or a clear defined sidelobe. The footprint consists of several small beams and a null of one beam could be on a sidelobe of another - as you can imagine it is wery complex. Astra do not need this information as the satellites mainlobe is whats supposed to give the official coverage aerea where Astra can provide high link availability (probably 99.998% if the right antenna size is used). Astra cant sell services based on sidelobe reception. [/QUOTE]

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