Multi-LNB Grief

[bingolittle]

Help me out here please! I’ve replaced the small (45cm) dish that came with my receiver with a larger second hand one (95cm x 110cm) for a 13deg/19deg/28deg multi-lnb setup. The problem is I can hardly pick anything up with it. I initially lined up the dish with the centre LNB on Astra 1, which I eventually found after a lot of fine alignment – the LNB sits a little bit higher with the multi-arm in place, but adjusting the dish elevation compensated for it. Off that, I can get about half of the transponders on Astra 1KR with 70% plus quality, but nothing off some of the other frequencies and not so much as a single thing from Astra 1H, 1L, or 1M.

As that seemed to be what I’d have to settle for, I tried to setup the other two LNBs. After hours that have since turned into days of very fine adjustments, slight alterations to skew and pushing the LNBs back and forwards in their holders the best I can get from Astra 2 is about 40% quality on about a third of the transponders (nothing off any of the Eurobird transponders, which are what I’m really after). Hotbird I can get about 35% quality on some, and nothing off others.

Where am I going wrong? The mast is bang on plumb, the dish doesn’t appear warped, there’s a clear line of sight, the cabling is all okay – I’ve temporarily mounted the flimsy 45cm dish nearby, and via the same cable it’s pulling in everything off Hispasat 1C with 60 to 80% quality. Bypassing the diseqc doesn’t make any difference either.

I’ve included a photo of the LNBs, in case that helps with diagnosis. Thanks in advance for any advice.

 

[rolfw]

You are way out with the outside LNBs, which only need to be two or three degrees higher or lower that the central LNB.

The main LNB should be sitting lower in the original holder, this is what it should look like: Ebay item number 220495410359

Or you can go for the Inverto kit : _http://www.sateuropa.co.uk/product_overview.asp?id=2158&catid=12&subcat=51


Below is one I set up a while ago, Hotbird main focus, then on the Western side of the central LNB: 19.2 East, then Astra 28.2 East.

 

[Robbo]

Hi,

First off, concentrate on getting the central LNB right, All transponders will be available on 19.2E then.

Take off that contraption you have on the central LNB, put it correctly in the holder, it will then work properly.

As for the two side ones, you need to find something better than you have there.

I tend to use the Triax multiblock on non-Triax dishes if there is no adpater available, it works very well, with some modifications here and there.

See below for a photo (sorry about the blur) of a 28E + 13E setup that I did using the Triax bracket.

There are also other brackets available too, that also slip over the central LNB, have a look on eBay, there are some thin plastic holders, they are rubbish quality, but they work.


Or get the proper bracket for your dish as highlighted by Rolf.