How many degrees apart can I go with 1.2M dish

dssnosher

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I have 1.2M dish. Is it possible to get 2 satellites that are approximately 15 degrees apart? One satellite requires 75cm and second requires 1.1M so I would use 1.1M as prime and 75cm as offset. Will this work?
 

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Is it an offset dish ?

Are the transmissions C or Ku band ?
 

Analoguesat

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Its more to do with the transmission powers - I happily run a 1.1m dish with the main focus on 46E & offset lnbs for Yamal 402 @ 55E & Hellassat @ 39E.

I only get the strong European beams, buts thats good enough for me.
 

dssnosher

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Offset dish and KU bad transmission
 

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Bad or Badr ?
 

Terryl

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With two satellites 15 degrees apart you will be pointing right in-between the two, so the dish only needs a 15 degree receive bandwidth, as the LNB's will only be 7.5 degrees ether side of center.

Just check the dishes receive beamwidth, but one thing, most round prime focus dishes are set up for only one LNB at the prime focal area, some round dishes would be OK, but the focus area of the signals 7.5 degrees off center may not be as strong.

This is why they came out with the elliptical dish, it has a much wider receive beamwidth then the single satellite dish, so I would look around for a 1.2 meter elliptical dish, you will be much happier with the performance, and will save a bunch of hair when trying to align the two LNB's.
 

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Terryl

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BlindFaith

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This is why they came out with the elliptical dish, it has a much wider receive beamwidth then the single satellite dish, so I would look around for a 1.2 meter elliptical dish, you will be much happier with the performance, and will save a bunch of hair when trying to align the two LNB's.

I don't agree. Looking from the satellite both prime focus and offset reflectors would appear as circles. If the width of the elliptical dish is equal to the diameter of the prime focus, both look identical from the direction of the satellite.

The problem is more to find a rail or something like to mount different LNBs. on a PF. For many offset dishes accessories are readily available.

15 degrees shouldn't be a problem but as @Analoguesat said, it depends on the signal strength :)
 

Terryl

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The shape of the prime focal area will be the shape of the dish, as you go off center with the signal the focal area can become distorted or oval shaped as you are now reflecting the signals from one side of the dish, it is not designed to do this.

Another thing is that a prime focus parabolic dish is designed to put all signals it receives (from one direction) into the prime signal focal area, you mount a LNB outside this area and your signal into it will drop.

Also to receive two (or more) satellites on a prime focus dish you have to offset the center of alignment, if the two satellites are 15 degrees apart then the dish must be offset by 7.5 degrees or your going to have a drop in signal on one of the satellites..

This is where an elliptical dish comes in handy, it can receive two or more satellites with a wider receive beamwidth.

One other problem with useing a prime focus dish for more then one satellite, is that your putting more hardware out in front of the dish, this can have problems with signal scatter, also some prime focus dishes cant be skewed to properly align the LNB's to the correct H and V axis, you have to use a bracket with a built in skew or one with an adjustable collar on it, this adds hardware out in front, go good.

So in my opinion the best dish for more then one satellite would be an offset elliptical, (gets the LNB's and mounting hardware out of the way) you will have a much better chance useing more then one LNB for more then one satellite.
 

Trust

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All the " problems" written above ( exept the shadow made by the hardware in front) are the same for a standard offset dish .
I dont see why skew for a multifeed setup at a PF should be a problem
 
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