Dish and mount

[lee32uk]

Hey all
I have a Diseqc mount which will take a dish up to 1mtr.At the moment i have an 88cm dish but i was thinking of getting a 1mtr dish in its place.The thing is, i have seen a 1.1mtr dish for £10 more.So would i get away with putting a 1.1mtr dish on a mount designed to take up to 1mtr ?
The manual says max antenna weight of 20Kgs and dish size 100cms.
If not then i will just buy the 1mtr dish.

Thx
Lee

 

[rolfw]

Its not only the weight, but the wind resistance of the dish Lee. I would guess that the increased size could place an undue strain on the mount.

If the dish is not in an exposed position you could probably get away with a slight oversize, similarly you may find that an exposed position may make even a 1 metre unacceptable.

 

[Old Satellite]

Rolf is correct you need to be carefull , when you increase the dish past the reccomended size of the manufacture, of the mount. is is normally for many of the mounts to have only a 20% margin.

When you consider the effects of the extra windloading during storm conditions of lets say 50-75mph then potentially the extra loading on the mount from a 1.0 mtr to a 1.1 although appearing to be small actualy results in approx an additional 20 % loading. for the supporting steel and mount.

Which mount do you currently have ? maybe some one has allready tried the dish with the same mount what you are thinking off ?

Is it the Triax 1.1 that you are thinking of fitting?

What additional channels are you looking to receive or to improve ? may be we can help or advice if this change will help ?

Old Satellite

 

[lee32uk]

Hi
The mount i have at the moment is a cryptik mount.I was going to buy a 98cm Funke dish to put on it, but then i saw the Triax 1.1 dish for only £10 more.As my current dish is a 88cm Triax one i know that they are good quality dishes, and also the neighbours probably wouldnt notice that i had fitted a bigger dish, as the dish would be the same colour )(-)( .The other thing is that i didnt want to have to fit another mount as it took me a while to get this one nicely lined up.
The dish itself is fairly well sheltered from the elements and i know that the wall bracket is capable of taking a 1.1 metre dish.
I may just settle for a 98cm dish to be on the safe side as i know that the extra channels that i want (Viasat) wont be viewable 24hrs even on a 1.1 dish, but a 98cm one will help with the signal quality on galaxie sport 10E.

Thx guys
Lee

 

[Channel Hopper]

In Manchester you may be lucky to get Viasat all time on the larger dish, unless it gets cloudy

Id take the chance

 

[Old Satellite]

Seems like a good idea to go for the Triax 110 its always best when the ones next door don't notace the differance!
and has Channel Hopper added the 110 should help with the weaker signals better.

Just check the mount, before you change along with the supporting mounting bolts etc and then schedule very few weeks to check that every thing is ok after the change. also watch out for storms and have a quick once over to make sure that all ok

Old Satellite

 

[2old4this]

Wind resistance is a function of the surface area of the dish. Although most dishes are slightly elliptical, we can consider it to be circular for ease of calculation. So its area is calculated as (roughly) pi times the square of the radius; this means that the areas of the 100cm and 110cm diameter dishes are:
3.1416 * (100/2)**2 = 7854 square centimeters
3.1416 * (110/2)**2 = 9503 square centimeters
so the bigger dish presents a (1-(9503/7854))*100% = 21% larger surface to any incident wind (which is where Old Satellite's 20% comes from).

I personally use a rule of thumb that typical tolerance of electro-mechanical devices is about 10%. So indeed be careful here.

But ultimately all of this depends on your location and on how exposed the dish actually is. If it's tucked away in a relatively wind-free corner somewhere, there won't be a problem.

But one good tip just in case you do get a storm is this: orient the dish so that as small a surface as possible is presented to the incoming wind. IE send it to a sat chosen such that in that position, the dish edge is facing the worst of the wind. You could also make this a habit when you're not using it for any length of time (nights, weekends-away).
Makes a world of difference.

2old