Satellite Communications/SFD

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Question
QUESTION: Dear Sir,

I have some questions:

1. What is Saturation Flux Density (SFD) if I want to understand it in plain terms or in simple english?
2. What parameter or device is altered on the satellite or spacecraft to change transponder SFD?
3. What is meant by "making the transponder more sensitive or less sensitive"?

Thanks and have a nice day
Makil

ANSWER: Hi Mr Makil,

Let me first understand whether you are a Satellite Communication Professional OR STUDENT. The answers depend on how you may understand and so I am asking this. OK?
Cheers/GTRao

---------- FOLLOW-UP ----------

QUESTION: Dear Sir,

Thank you. I am a student as well as working in my part time to gain some satcom experience.

Thanks
Makil

Answer
Hi Mr Makil,
Good to know your interest in Satellite Communications as a STUDENT.
The terminology is to be understood from the point of Link Budget Calculations in SATCOM. There are at least three major components in arriving at the design of a Teleport or Earth Station. The most important being the Satellite parameters which User has no control. The other two concern Uplink ES and Down link ES.
The parameter in your question is a design specification for Satellite Operator and The Monitoring Ground Stations take necessary corrections in the Transponder parameters looking at the health of performance.
Your theoretical calculations to get higher gain etc are not the concern of Satellite operator, but overall performance is their concern.
What theory tells you is NOT exactly how systems are used under OPERATIONAL stages.

As a student you may not be needed to go into details of Hardware used in Satellite for changing parameters, but good to know your interest. You will know about these details when you learn Satellite Transponder Bus designs.
For your information SFD is the maximum Power Flux Density at the Satellite Receive Antenna (without antenna gain added) that protects the Front End perform without saturating.

Cheers/GTRao

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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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