Advice Needed Do multi LNB brackets with support arms exist?

[Xiaomi]

I'm potentially installing two dishes - 90cm for KA-SAT 9E and 60cm for Sky Q & Freesat.

What I am considering is to mount both onto a single dish and use a multi LNB bracket. My problem is that I live in an area with high winds and I don't believe that the bracket would remain in position for long regardless of how well it was set up.
To avoid this I think the bracket would require support arms bracing it to the edge of the dish.

Can such a setup as this be purchased or would it need to be a developed my myself?


Thanks.

 

[RimaNTSS]

I think it is easy to develop yourself. What kind of dish you are going to have your bracket installed? Can you show some pictures?

 

[Xiaomi]

Thanks - I'm not sure yet. I've been in contact with an installer, but there are some issues with what I want him to do so I might end up doing it myself.

If I did end up doing it, I would probably opt for the following (based on no real technical reason):

Smart 90cm Satellite Dish

In relation to the actual LNB bracket maybe sommething like this (no need for 3rd holder):
3 way LNB holder

 

[Ghostleader]

Mate I stay in the west of Scotland where 90 to 100+ miles an hour winds show up in summer let alone winter, mine have always been fine, no support arms added.

 

[william-1]

This home made multi Lnb setup worked for a few years with no problems.
28.2E + 19.2E + 13E on a 88cm dish.

 

[RimaNTSS]

@Xiaomi Usually, after strong wind problem can happen to antenna (when it turns around the mast) but not LNB-brackets. So, do not worry, get any antenna and multifeed for it.

 

[jeallen01]

In my (limited!) experience, the types of LNB brackets (commercial and "home-made") shown in the posts above won't suffer much in high winds because they are very short.

However, if you use/make brackets that are a lot longer than those, then support arms at the outer ends may well be necessary, and not just in high winds, because they will have a tendency to move up/down due to the wind and/or any accidental contact by "something else" (such as my head/arms on the brackets on my dishes which are at ground level!) as a result of the natural flexing of the bracket(s). Also, if one of the brackets is much longer than the other, then there is a tendency for the sheer weight of the bracket and the LNB(s) will tend to cause the whole arrangement to droop on that side. Either/both of those factors is likely to make it difficult for you to ensure that the outer LNB(s) stay accurately aligned on the relevant "sweet spot(s)" on the dish.

 

[Xiaomi]

Thanks for the replies. I'll see what the installer is able to do and take it from there.
Not having done this before, how much alignment of the LNB bracket is possible prior to mounting in position?
I am aware that there will be some fine tuning required to get the LNB positioned correctly, but for example is it possible to get use a bit of trigonometry to get bracket position finalised prior to mounting? Idea is to allow any supporting arms etc to be fabricated whilst on ground.

Is there any dish sizing issues I could face if I opted to do it myself?


I think my setup should look similar to this although the 28.2E LNB will be have 6 outputs. This is a 97cm dish so there is quite a bit of separation here:

 

[Ghostleader]

Ground mount or fix the dish to a post or indeed wall mount with just two coach bolts because it's temporary ect, align the setup, then remove the LNB holder with the multi LNB rail still attached minus the cables obviously then it's setup for the dishes permanent location, if your house/back garden lacks line of sight to do this then a friend or family member who stays local could help by letting you setup there before then packing it up to take home ready for installation in its permanent site.

 

[a33]

There are multifeed dishes with support arms, such as Visiosat/Cahors Big BiSat, and Wavefrontier T90, and I believe there was some Triax (or other brand) too? For just two LNBs maybe a bit overkill...

When you buy a multifeed rail, be sure it fits to your dish-arm! Otherwise buy or make a multifeed-holder that fits over a central LNB ~ You'd have to use a central LNB then (at 19.2E?).

Goniometrics beforehand: The tilt for the dish or rail for the two outer LNBs can be calculated approximately beforehand, undependently of dish size, solely dependent on your location.
For the distance between LNBs you'll need to determine the effective focal length of you dish, and then an approximate distance can be calculated.
I'm not sure which method is the best for that, though. I've seen some methods, and there are calculators with unknown methods, but I 'm still puzzled a bit for what would be an EXACT calculation (same goes for dish tilt calculation).

Greetz,
A33

 

[RimaNTSS]

I, personally, do not see the need for calculating of the position of multifeeded LNBs. When central LNB in place and dish is tuned to maximum performance than all other LNBs are adjusted manually - to the maximum signal on them.

 

[a33]

Well, a rough calculation is also an indication of how long the multifeedrail should be.
It would be a pity to buy or make one that turns out to be too short......

However, I agree with the motto: Always check, if you can improve your signal level!

greetz,
A33