Multi LNB setup, some issues

[NWW]

Hi all, a couple of months back, using this site for advice, I mounted my first dish using a triax TD88 and 3 invero blacks octo lnbs. The satellites pointed at are 13, 19.2 and 28.2E. On the first two, reception is top notch. I am almost centred around 19.2E, and the other two are offset. Now the the problem is that on the 28.2E satellite, when I scan for channels, it starts at around 70% signal quality on the lower frequencies, but then drops to around 30% on the higher frequencies, and some of them wont even lock. I was watching the BBC HD tp the other night under heavy rain, and it was struggling at 47%. Now what I'm wondering is if I did something wrong during the setup? Should I move the dish or the LNB? Location is Belgium, and receivers are two DM800HD, one Samsung TV, and 6 DVB-S2 tuners in my HTPC. Thanks! (ps: for the love of me, I can't add spaces on Windows 8/Metro style browser! It's like the enter key won't work)

 

[Lazarus]

Leave the dish at 19E and try adjusting the offset LNB for 28E. Do not forget to adjust LNB skew.




PS: What is this "Windows" thing of which you speak ....................... ?!

 

[Analoguesat]

You should have plenty of signal from 28E in Belgium - especially off Astra 1N which carries the BBC channels.

If you cant tweak the 28E lnb up any further try changing the outputs around on the 28E lnb, its just possible that one or more of them have a low output. Have you set the skew (twist) of the lnbs correctly - the ports should be pointing at about "7 o'clock" as you look at the dish.

Failing that swing the dish eastwards a bit to bring 28E closer to the main focal point, and push the other lnbs out a bit.

 

[sonnetpete]

I'd try adjusting the LNB, it may well want moving up or down. As you are using Octo's it may well have slipped. Also try moving the LNB towards and away from the dish in it's holder. I also found using my own TD88 (which currently holds 7 LNB's) that the arm 'dips' and you could try pushing it up slightly by putting a packing piece in the space underneath where it folds up into the dish....

 

[Analoguesat]

Multi snap!

 

[sonnetpete]

Link to the thread I started showing the 'mod' on the TD88

http://www.satellites.co.uk/forums/topic/153652-triax-lnb-feed-arm-problems/

 

[NWW]

Wow, didn't expect this kind of support so soon ^^ I appreciate! I will try and do that. The skew is I believe set already correctly, so I assume that pete is right and it might need some tweaking. I will also check that thread you linked pete, thank you again. PS @ tivu: it's the devil itself on a desktop ^^

 

[NWW]

An update to this:

I have completely removed the LNB's, and added them again, along with a fourth one for 9E. So on the Triax multiLNB holder it goes likes this: (seen from behind the dish)

9E-13E-(center of the LNB arm)-19.2E-28.2E.

19.2 is as close as possible to the center of the holder. I had some issues at first with high frequency transponders on 19.2 not showing up, and only 70% SNR on Hotbird, and down to 40 on 28.2. I took it all down, applied some basic trigonometry using the distance from the center of the dish, and the spread between LNB's and spaced them out to the millimeter, added 9E, and set it all up again. The results are amazing!

9E: 80% to 90% SNR
13E: 90% to 100% SNR
19.2E: 95% to 100% SNR
28.2E: 80% to 100% SNR (on the BBC One/Two HD transponder!!!!)

So all in all, it was an alignement issue as suggested! I'll take a picture shortly!

 

[Lazarus]

Excellent news - it's always good that people report the outcome of their Projects.

 

[Analoguesat]

Ah great - its brilliant when folk get their systems up and running correctly.

 

[NWW]

Here is the photo I promised.

It's still a mess, there should be 28 cables coming out of the 4 LNBs, but I can't seem to find a proper way to hide those cables.

Any ideas?

 

[Piltdownpaul]

Nice work, depends how fussy you are about cables, i like to keep mine very tidy!

 

[timo_w2s]

Nice setup and result. I've got a similar problem with cables but as I'm using single and twin LNBs I don't have quite so many sprouting out of the dish. Sat coax is such a pain to keep neat when it's in large quantities.

 

[NWW]

Thanks,

But I hate cables x) that's my strugle right now.

 

[Archived-1]

nice set up, I would shorten all cables and fasten it all to the wall, you could even build a box around it with a little door :-).

 

[Analoguesat]

Some brown or black box section conduit screwed to the wall?

 

[NWW]

Thanks for the suggestion.

I should work out a way to screw the switches on a board and route the cables on that board, then cover said board with a box. The problem would be the 24 cables coming out of the dish, over the stone on top of the wall in that picture. I'd love to hide them as well.

Do you guys think it is possible to attach a pipe Under the arm of the dish?

I think I may also investigate routing the cables from the outside of the wall (there is a gap between the wall on the picture and the house, about 15 cm wide, I could use that)

Never thought I'd enjoy this so much ^^

 

[Archived-1]

just buy this ebay Item number: 270787198748 and a piece of straight pipe then feed all the cables through it into a box on the wall :-)

 

[NWW]

Thank you Martin.

That particular seller doesn't send to Belgium, but I have local hardware shops that I can parse materials from.

This'll be my project for the summer for the time being, I'm finally glad being able to watch some TV.

I'll post the results when I'm done

 

[Analoguesat]

Do you guys think it is possible to attach a pipe Under the arm of the dish?

Why not give it a try - just get yourself down to your equivalent of B&Q and get some cheap drainpipe & an angled section. Run the cables through the pipe and fix the pipe to whatever box you install on the wall (sealing it well of course

Probably easier though to get some box section conduit screwed to each side of the wall & run it through the gap in the wall. Then just clip the cover bacl on when you have finished - if you do this remember to drill holes in the bottom to allow rainwater to run out, as it will get in eventually.


EDIT - Must type faster!