Satellite Antenna Array

[AhmedGalal]

How can multiple small antenna satellite dishs replaces large one "say 240cm" ?
What's the algorithms to combine individual gains into strong one gain ?

 

[david401040]

very cool question I look forward to seeing the answer too

 

[davenn]

you query needs a little more info

multiple small dishes equalling the same size of a larger dish ( so closely packed ?)
multiple smaller dishes spread out over an area larger than the area of a single large dish ?


just as a starter
if I have a 10 element yagi with say 10dBi gain and I add another 10 element yagi in phase with it
I have doubled my gain ie. added 3dB so now I have 13dBi of total gain
I have to double that again to 4 yagis to get another 3dB gain taking me to 16dBi

To get another 3dB gain I would have to go from 4 to 8 yagis and so on

get the picture ?

Dave

 

[chuckey]

The above assumes perfect power addition. In real life there will be a problem of phasing up all the combiners so the RF all adds up, so there will additional losses.
Frank

 

[davenn]

The above assumes perfect power addition. In real life there will be a problem of phasing up all the combiners so the RF all adds up, so there will additional losses.
Frank

yup indeed, just giving the basics

 

[chuckey]

Just thinking out aloud. 16 "small" dishes at 1m diameter mounted on a frame would occupy the same real estate as one 16m dish in terms of rotating the array. but the feed and power splitters do make for a big problem, especially for transmission - a lot of microwave feeder to be fed with dry air. Its wind resistance would be substantially lower. All sites that require a lot of aerial gain use just use the one large dish. it could be beneficial if the physical space was limited to mount smaller dishes in line to squeeze them in, say up the face of an existing aerial structure.
The nearest thing to this I can think of are the multiple phased dipole arrays used by the military for tracking fast moving object via radar, such as falling mortar shells. This is where the actual aerial pattern is electronically " rotated", which can be done much faster then swinging a dish about.
Frank
See ~:- https://en.wikipedia.org/wiki/Parabolic_antenna

 

[jiripolivka]

Interferometer arrays are good for narrow-band signals, using it for a wideband satellite signals will not bring a good result.
You may notice nobody uses such solution for sat-com

 

[AhmedGalal]

Thank you all friends ....... I get it .