Advice Needed 28.2e/19.2e/13e/9e and 12.5w - t90 or t55?

noco63

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Hi all,

I've been making do with a 1 metre dish and multi-LNB setup for 13E and 19.2E, with a separate dish for 28.2E. I was thinking of replacing this with a torroidal dish, with quad-feed LNBs. 9E will be KA-band. My main interest is Italian, German and Russian channels. I'm located in the North East of the Republic of Ireland. Would a T55 suffice here or do I need to go for the T90? Any advice much welcomed.
 

ozumo

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Forget 12.5w, there's nothing to watch at that position. 9e + 13e might be too close to work on a T55, I believe the specs say minimum spacing is 4.5 degrees, so some bodging may be required. 5w may be of interest for the Italian channels but they are expected to leave soon and move to an all but unreceivable beam on 9e. 5w would also need the T90 but I can't guarantee it would be large enough for good reception at your location.
 

daro2096

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13 + 9 might work if the LNBs are the 23mm slim type on a T55 otherwise some bodging as the poster above this one has already said. The two satellites are of the same signal strength at least for most channels on 9e. But forget 12.5w. If you are looking to have 28.2 to 9e on the same dish you won't get 12.5w anyway, they are too far apart. Well if dish is centred on 19.2 or 13e.
 

daro2096

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Anyway there is nothing at 12.5w except feeds which a receiver will not pick up unless there just happens to be a feed being transmitted at that time. It is a waste of time and money in my opinion.
 

ozumo

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This recent post shows 9e + 13e works:
 

daro2096

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One of the two has got to be off centre, either 13 or 9. The LNB holders without any LNBs touching will be 4 degrees apart and that is touching. When you put the LNBs in the holders they will be further apart, 4.5, 5 degrees so one or both will be off centre. The only solution is to use rocket style slim 23mm LNBs.
 

ozumo

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There are plenty of 40mm LNBs with smaller feed horns - Inverto eco green for example. Do you own, or have experience of using a T55?
 

daro2096

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I got a T55 ready for install. Had it for a year nearly. Just haven't got round to putting it up yet. Lack of money and of course corona has delayed things.
 

ozumo

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Here in the North East, 9e & 13e are very nearly 5 degrees apart
Code:
https://satlex.de/en/azel_calc.html
 

a33

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Here in the North East, 9e & 13e are very nearly 5 degrees apart

Well yes, but the azimuth value is not what makes the difference there.

E.g., when you are at the equator at 11east, the azimuth difference is 180 degrees, but the satellites are only 4.7 degrees apart....

In practice though, at these latitudes, the azimuth difference value sometimes is near the separation angle of the satellites, so as an approximation it can work.
And I think the Polarmount Hour Angle, that is given by satlex, is also not precise at determining the angle between sats. (I did not succeed at calculating the angle between satellites out of the two corresponding hour angles; I calculate that differently...)

But let's get back ontopic, to T55/T90.

Greetz,
A33
 
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