The best position for further LNBs to point at is the same position that the primary, central LNB points at. If a secondary LNB is not also pointing at this primary position .....
Well, I guess you still think the pointing of the LNB is quintessential, and that you haven't read the thread about the 'horizontal G-spot'? Alas.....
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And have you checked pictures of the Visiosat BiSat G3D-bracket with 4 LNBs? What do you say about that, then?
Can you confirm that you have measured the angle between the feedhorns in various monoblocks and that they are not parallel, and also different for monoblocks for 80 cm dishes and 64 cm dishes?
Maybe that needs clearing up first. Now we are talking along non-touching lines.
Maybe for your dish size you could try a 4.3 degree monoblock or a 6 degree monoblock for a 80cm dish.
Though they are designed for a different dish size, the distance between the two LNBs inside
might be approximately what you need on your 1-1.3 meter dish.
But it really is 'might'. Separate LNBs give much more fine-adjustment possibility
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@Tom W H :
The reason I said 'might' is that the range 100cm-130cm is pretty much, so you would need to be more precise there.
Furthermore we don't know, if that dish has the same f/D as a 'normal' 80 cm dish.
And thirdly, a bigger dish has a narrower beamwidth, so the LNB feedhorns in the monoblock have to be more precise in their right spot; a bigger dish is 'less forgiving' for that.
So if a monoblock for 3 degrees would be exactly fitting for a 80 cm dish on your location, then a 4,3 degree monoblock for a 80 cm dish would be fitting exactly on a ( 80 x 4,3 / 3 = ) 114,666 cm dish (with the same f/D) on your location for the 3 degrees separation.
However if there would be a misfit with the 3 degree monoblock on your location on a 80 cm dish, but the dish is 'forgiving', then you could still have reception on the 80 cm dish, but you would multiply
(with the above kind of calculation; edit A33) the error for another dish size, with possible dramatic results (no reception).
You would then have to calculate the LNB distance from the effective focal distance of your dish and the angle difference between the two wanted satellites at your location, to see if there is a monoblock with about that calculated internal feedhorn-distance
A problem of a monoblock is also, that after tilting the monoblock to its proper angle for the both satellites, you cannot adjust the skew of the LNBs anymore. Some monoblocks are preskewed, but the information about that is difficult to find. That is a problem not linked to dish sizes, though. But if you have room for normal LNBs on the bigger dish, with seperate LNBs you have much more adjustment possibilities.
greetz,
A33