noise temperature of receiver at LEO orbit

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ahmer saeed

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Please tell me what is the noise temperature of receiver at LEO orbit due to sun and other atmospheric conditions.
 

the contribute due to the sun and the earth only are:
quite sun: typically 6000K 8depend on freq)
earth: worst case typ. 300K
But i don't know if other aspects shoud be taken in consideration (ionosphere?, other ?)
The sun contribute shoud be calculate by a convolution of the solid angles of antenna beam and the sun beam. Pratically with large antenna beam the sun give a more little effect than 6000K
 


Is this the receiver noise temperature or the noise temperature seen by the receiver ?
:sm18: :sm18:
 

I believe it is antenna temperature.
 

It is a temperature seen by the receiver.
 

It is a temperature seen at the antenna port!
To arrive to the receiver thre could de further losses to be accounted for!
 

Noise temperature is a measure of system performance.

It depends on many factors... this temperature can be increased if the sun enters in the radiation lobes of the antenna, this produces an increase on the system temp.
A side effect of this is that a weak signal could became not detectable.

Such problem happens for GEO satellite that experience what is called "sun outages".
 

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