Where am I going wrong?

[moordown66]

I’ve set up fixed dishes many a time and have been helping a friend with his. It’s an 85cm (I think) dish and we’re looking to line up Astra 1, Astra 2 and Hotbird on it. The dish in question is an Inverto Multiconnect with the slim LNB’s. see here -http://www.inverto.tv/products/product.php?section=3&id=112&cat=19]
I have set up Astra 1 as prime focus with Hotbird to the right of it as you look at the dish. I’m getting fantastic strength and quality off of these two but I’m really really struggling to get a decent fix on Astra 2. There are no obstructions and I simply can’t see why we’re not getting it properly. For example – getting about 40% picture quality off BBC HD. I’ve done this so many times on my own heath robinson set up’s without any trouble at all.
Anyone got any suggestions for me as I’m baffled!

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[Topper]

I would have thought 85 cm would be too small for a triple lnb set up but am willing to be proved wrong

 

[moordown66]

I've got it working at home on an old 80cm 'analogue' Sky dish so as far as I can see 80cm is absolutely fine. Maybe being in the SE help with that? So I don't think that's the problem.

 

[satelliteman]

You need to account for the elevation differences. Astra2 is lower in the sky so the LNb needs to be raised on the bracket.

 

[moordown66]

Yep - done all the but to no avail. Have a look at the link - you'll see the bracket rises itself. Have tried it more/less left/right but to no avail. Wi=ondering if it's something specific to the dish design?

 

[satelliteman]

I would guess you don't have the correct dish alignment then.

Take the LNb off and try for 28e by hand.

Can you post a picture of the dish so far.

 

[Lazarus]

Well the skew of that 28E LNB could be critical ............ as you are "out on a limb", so to speak, the efficiency isn't too hot to start with (though I think it should be ok if properly done).

You could try to calculate the required skew, but 28E is an odd beast anyway as there is "pre-skew" built in by the way the Satellites are orientated and set up.

So try altering the skew of the 28E LNB by experiment and see if that improves matters.

 

[moordown66]

I can probably get one tomorrow. Where could I have gone wrong with the alignment, bearing in mind I've got Astra 1 and Hotbird in so massively?

 

[Lazarus]

I can probably get one tomorrow. Where could I have gone wrong with the alignment, bearing in mind I've got Astra 1 and Hotbird in so massively?

As stated, perhaps the 28E LNB skew needs tweaking?

 

[moordown66]

Here's some pictures. The one with the whole dish pictured is l-r Astra 2, Astra 1, Hotbird.

 

[Lazarus]

Is that an In-line Amp I see?

Is it in the 28E feed?

Best to remove it or you are likely to get misleading results during alignment.

They are only for compensating for losses on long cable runs and they cannot improve the Quality of the received signal - because they add Noise of their own.

 

[moordown66]

It was an experiment. Will take it off, but alignment was done without it.

 

[Huevos]

Here's some pictures. The one with the whole dish pictured is l-r Astra 2, Astra 1, Hotbird.

Mate that is set up so wrong. Start by skewing the bar 15º. You want the east end of the bar lower than the west end. So the west end of the bar is about 12 minutes past and the east end is 18 minutes to.

Also, by the look of it, both the 28ºE LNB and the 13ºE LNB are higher than the 19ºE LNB. The 13ºE LNB should be the lowest, next 19ºE and then 28ºE is highest.

Doesn't appear to be any LNB skew either, and in fact 28ºE LNB looks to be skewed in the wrong direction.

What is the location of this set up?

 

[Lazarus]

On closer inspection, that Amp is in the 28E Feed.

To be honest, not only would I remove that, I'd also remove the DiSEqC switch and connect the main cable direct to the 28E LNB for now.

Amp = Noise

DiSEqC = Loss

Go "au naturelle" until you're satisfied with 28E.

 

[satelliteman]

As mentioned in post #13, the LNb for hotbird should be below the height of the prime LNb. It's a mirror image of the East side arc.

Make sure you align the dish on the prime as suspected you've tweaked to get 13e in.

 

[Lazarus]

And just for clarity, the 40% Quality figure you mentioned for BBC HD at Post #1 .............. I assume that you actually have no picture at all, as opposed to a marginal one?

That being the case, the Quality reading you get will be the quiescent one that indicates little more than than power is reaching the LNB. If you massively detune the dish/LNB you'd get a similar reading ................ (and. of course, no picture!)

 

[Robbo]

Assuming that the dish is on 19E, the 28E doesn't look to bad, the 13E is way off as already said.

What you can di is to unbolt the lnb, and slowly move it about until you find the right spot, then clamp it there.

BTW, pic below may help, I think its the same dish, its one I'm working on at the moment, all 3 sats 28E,19E,13E working very well.

 

[moordown66]

Thanks for the info. Will try and answer the questions.
Set up is in Herts,
Getting a huge signal and quality from Astra 1.
Getting a huge signal and quality from Hotbird....so if it's way off as mentioned, why move it? The issue isn't with Hotbird.
Am getting a picture off BBC HD on Astra 2 with occasional break up. Quality is 40%, not strength.
Will try these suggestions out tomorrow and see what happens.
More suggestions are always welcome!

 

[Robbo]

Ahh, you posted justed as I was editing, see new pic added, may help.

 

[Huevos]

Getting a huge signal and quality from Hotbird....so if it's way off as mentioned, why move it?

Because it's not in the right place. If you have 3 LNBs on the bar and one is set so far out it can be seen in a photo it is certain there is a knock-on effect to the other LNBs. BTW, robbo's picture is really helpful because it shows how the bar should be skewed.