Satellite Communications/Satellite FCA & SFD

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Question
Hi Sir,

I want to ask why satellite operators don't set FCA at maximum (no attenuation) so that SFD value is lowest. If SFD is low, uplink power needed is smaller so we just need smaller antennas and BUCs.

Thanks...

Answer
When the padding or attenuation is reduced, the satellite operator is configuring the transponder to
be more sensitive or increasing its gain. Increasing the sensitivity in the transponder allows the introduction of more noise into the system, due to the higher sensitivity.

In Satellite Communication we should be more concerned about Transponder availability during its Lifetime and never consider whether we need to Uplink high power or Low power. When Link budget is handled, all satellite parameters of Operator are specified keeping satellite and Transponder design performance and efficiency.
And making Transponder sensitive is not just for signal but to noise also, so there is no purpose served because overall Link Budgets consider Up and Down C?No and NOT just Carrier power.

Cheers/GTRao

Satellite Communications

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TIRUMALA RAO G

Expertise

Satellite Communications Applications, Link Calculations, Teleports, Earth Stations,VSAT, Tracking, Mobile Communications, Next Generation Networks.

Experience

40 Years. Indian Space Research Organisation, PANAMSAT, Satellite Based VSAT Networks, IP Networks.

Organizations
ISRO, PANAMSAT, Engineering Institution for Higher Education (GVP College of Engineering), Consultancy.

Education/Credentials
Graduate in Electronics and Communication Engineering with Distinction. Guiding scholars for their Doctoral thesis in related areas in Academics.

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