Help needed with triple LNB setup on fixed dish

[JM900]

Had a friend set up this system for me, my aim was to pick up 28.2e, 13e, and 19.2e satellites. He suggested placing it on the side of the house due to some trees disturbing the line of sight were it to be placed on the ground.

In short, it's been disappointing since the start, I'm using 3x 0.3dB Invacom LNBs which I was told should be able to get those three satellites in conjunction with the disecq switch and 90cm dish. This is my first satellite setup so would like some pointers from people with experience as to how best to proceed.

Basically, I live in the Highlands of Scotland and we get very high winds and frequent too...I think we underestimated how robust the thing needed to be. The main silver bracket affixed to the wall is rock solid but the arm of the dish and the dish itself wobbles considerably in high winds. The bracket I got too has broken in the middle(cheap plastic) but even before that we had issues getting all 3 satellites stable without breakup(someone suggested I might need a curved holder rather than a straight one)

So I would be interested in what would be the best way to continue. Would it be worthwhile to take the dish off the wall and put it on the ground(away from trees blocking line of sight) I have plenty of space landwise so this would not be a problem neither would building a concrete plinth etc for stability. Secondly, could I get a stronger arm and bracket? and would a curved LNB holder be better bearing in mind the three satellites I'm after. I'm just really frustrated with adjusting one LNB which then throws the other off and I can't get decent SNRs on all three satellites together. Like I say, I really don't know much about this and the friend who installed it for us has moved away leaving me with this picture that is constantly breaking up and glitching. Thanks in advance to all that can help.

 

[Analoguesat]

First thing to do is get the mount sorted - those J shaped pressed steel dish mounts have the rigidity of wet cardboard so its no wonder you are having problems with a heavyish dish - the merest zephyr of breeze blowing past will make the dish wobble and bounce like the boobies of a braless gogo dancer..

Get a set of T&K brackets and a piece of steel scaffold tubing or the equivalent and you will have a nice firm mount.

As long as the dish has a good line of sight the dish doesnt need to be high up so you could drop it down to ground level if the los is clear

 

[JM900]

Is the mount it's on that bad? I got the impression just looking at it in high winds that the picture breakup was more a result of the flimsiness of the arm, also could you suggest a bracket that would take 3x LNBs that would be suitable to get the three satellites I mentioned? From what I've read the procedure is to have the weakest satellite set up in the middle LNB and obtain maximum strength on that one then adjust the other 2 relative to that, is this correct and how do I go about finding out which is weakest? sorry for all the questions! I'm realising now that I probably should have opted for the Raven Gemini setup for ease of setup but if I can avoid it from a cost point of view I would like to try and persevere with my current setup.

 

[satelliteman]

That's not a 90cm [or doesn't look like it anyhow], more like a 65cm in which case it's too small. Also those offset brackets are not the best and require a lot of fiddling to get a satisfactory on all satellites.

Get yourself a Td88 or Gibertini85 with the correct LNb offset arm

 

[phazblade]

You really neeed to get everything solid or you arnt going to get stability.

Also your Multi LNB Arm shouldn`t be level, is should be like this, see below

19E is in the Centre, 13E on the Right, 28E on the Left, but notice the angle

 

[Analoguesat]

Is the mount it's on that bad?

Yup Its probably ok for a Sky minidish in a sheltered location.

Go outside next time its blowing hard - probably tomorrow in the Highlands! - and see how much shimmy the dish has.

Oh and get the lnb arm slewed round like the picture above in phazblades pic

 

[Robbo]

If you could put a dish at ground level, it would be much easier for you to adjust and fiddle with, to get all three LNBs spot on. Also it would obviously suffer less from being blown about in the wind.

I believe the curvature of the multibracket depends on the dish. The Triax multiblock brackets are curved, and that helps to get the offset LNBs pointing at the dish centre and to get them the right distance from the dish. The Raven Gemini for axample has a straight offset arm, and works fine on that dish, but I suspect that the dish is shaped so that it does.

Changing the dish to a TD88 as already mentioned, making the necessary tilt on the arm, and adjusting the dsh and LNBs appropriately will solve all your problems. You should get a strong signal on all three sats, without too much of a problem.

A really sturdy dish with a very firm LNB arm is the Hirschmann 85cm, in case of stong winds, however I'm not sure that there is a multi-LNB arm available for that, there may be as Triax make Hirschmann too.

 

[nelson_b]

how far north are you ? --
the signals do weaken a bit in the "far north west" on all 3 sats --
as i,v noticed when on holiday there whilst setting up my caravan dish -( all the sky-dishes are zone 2 size ) -
so i think a decent sized good quality dish would help if this is the case --

cheers nelson.b

 

[JM900]

Thanks for all the responses guys, I'm based in the Western Isles (Stornoway) wind is really a problem, didn't want to have the dish as high as it ended up being but like I say, the rows of trees kind of made it necessary to get a line of sight. Analoguesat is right, in fact I believe it was the movement of the arm that caused the LNB holder to break, really bad design. From the comments it seems like the natural option to go for would be to go for a TD88 since it appears to be a recommended dish and it also has the advantage of the multi-LNB bracket designed to fit it. Ideally I would like to keep it on the wall just to save the hassle of relocating it on the ground, looking at the Hirschmann recommended by Robbo the arm looks really strong and I suspect would definitely allow me to keep it fixed on the wall, but there isn't a 3 LNB holder I can find that is suitable, so I'm still unsure.

 

[Analoguesat]

I can imagine it gets a tad windy up there at times

You might be better off with 2 fixed dishes. A nice sturdy pair of T&K brackets with 6 feet of steel pipe will give you a cracking mount for 2 dishes that wont move under anything short of a hurricane.

You dont have to use official lnb holders you know - you can probably knock up something just as functional even if its not as pretty. I ran a 13E / 9E dish for a year with the second lnb zip tied to the 13E lnb

Wasnt pretty but it worked just fine - if I did that again I'd use gaffa tape as well.