Combining signals from LNBs

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Pmartin252

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#1
Apologies if this has been asked before but... I live on the Costa Blanca and would like to install a system to view BBC channels etc. I know that a large dish (2.4m + ?) is required. This is not practical in my location, but It occured to me the other day that it might be possible to use say 3 x 90cm dishes. Is this viable? can the output from 3 LNBs be combined and would this give the same signal as a 270cm dish?

Please help,

Regards
Martin
 
Analoguesat

Analoguesat

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#2
It doesnt work like that. Buy the 2.4m dish or do without.
 
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jphili

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#3
While it is theoretically possible, it's almost impossible to join the signals of the different LNBs without any phase difference.

Plus your math is of, it's surface that counts 2.4m => 4.52m2
90cm => 0.63 m2
So you would need 7-8 of those smaller 90cm dishes for the surface of the 2.4m one.
 
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Analoguesat

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#4
Its theoretically possible alright - this is exactly what astronomers do with their multiple array telescopes.

Even though its possible, its financially idiotic - far far cheaper to buy the 2.4m dish in the firstplace:D
 
Prophessor

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#5
Not where I come from. But if someone ever does a nut job like that I would like to know the results. :)
 
Analoguesat

Analoguesat

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#6
Prophessor said:
Not where I come from. But if someone ever does a nut job like that I would like to know the results. :)

Dont think its every been done on a hobby level - the engineering cost would still make it cheaper to buy that big dish.
 
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#7
No, it's not possible. The down-converter oscillators in separate lnbs aren't "correlated", all you'd get would be electrical noise.
 
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marac

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#8
But If I send signal on the second dish from first dish before beam even enter the LNB (raw signal)? Is that possible ? Will it works ?

After signal is reflected from the dish in the focal point, than reflect the signal to second dish (in the second dish's LN:cool:

It seems with a lot of send , especially if you have a lot of fixed dishes, so you can use on every dish focal point for one particular satellite.

For example, if you have dished pointed to 19E,28E,1W,13E, you can use the focal points (signals) for 28E on every dish(19E,1W,13E) and transport it to LNB on dish pointed to 28E.

Why not ? Question is will it work and how to make a reflection?
 
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divibi

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#9
spiney said:
No, it's not possible. The down-converter oscillators in separate lnbs aren't "correlated", all you'd get would be electrical noise.
Can these oscillators in separate lnbs be somehow "correlated" at the manufacturing level "by design", or sourced by 'trial and error', or modded?

I read that it's very easy to link dishes in C-band, but it becomes less effective in Ku-band. How does it work?
 
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Rd100

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#10
it is very easy get about 10 mini dishes then get a roll of tape and twist all of the cores and braid of the cables together so you then have 10 cables going in to 1 then plug the receiver in and run:-rofl2:),


Pmartin252 said:
Apologies if this has been asked before but... I live on the Costa Blanca and would like to install a system to view BBC channels etc. I know that a large dish (2.4m + ?) is required. This is not practical in my location, but It occured to me the other day that it might be possible to use say 3 x 90cm dishes. Is this viable? can the output from 3 LNBs be combined and would this give the same signal as a 270cm dish?

Please help,

Regards
Martin
 
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