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Converting A C-band Dish?


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Old 15-01-2006, 15:00
jimmyboy32
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My friend has an old C-Band dish. I'm sure its 3m anyway and made of a meshy type material with an arm coming out the middle of the dish for an lnb.

Would it be possible to convert this for use with KU Band?

Its the spit off this dish?
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Old 15-01-2006, 15:02
rai man
 
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As long as it is parabolic (It will be) and he finds a way of placing a Universal LNB at the focal point, no problemo.

Camouflage slightly more difficult!
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Old 15-01-2006, 15:05
jimmyboy32
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Originally Posted by rai man
As long as it is parabolic (It will be) and he finds a way of placing a Universal LNB at the focal point, no problemo.

Camouflage slightly more difficult!
Its a bloody ugly thing. He can get quite a few channels on it (Nothing of any use I might add) but picture quality isn't great
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Old 15-01-2006, 15:10
SteveMcK
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Originally Posted by jimmyboy32
My friend has an old C-Band dish. I'm sure its 3m anyway and made of a meshy type material with an arm coming out the middle of the dish for an lnb.

Would it be possible to convert this for use with KU Band?

Its the spit off this dish?
It will depend on the size of the holes in the mesh. If they are bigger than 5mm or so then the dish will not be very efficient in Ku band. Smaller than that and it should work, if you can get an LNB that fits the mounting.
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Old 15-01-2006, 15:39
mob227
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I have a 3.1m dish i use mine for c & ku band as im useing a chaperrel co rotor 2 feed horn on it, but if you want just ku band you will need the right feed horn on it for your dish and if you want to use a universal lnb you will need a c120 fitting one,

Originally Posted by jimmyboy32
My friend has an old C-Band dish. I'm sure its 3m anyway and made of a meshy type material with an arm coming out the middle of the dish for an lnb.

Would it be possible to convert this for use with KU Band?

Its the spit off this dish?
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Old 15-01-2006, 15:54
eureka
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Originally Posted by SteveMcK
It will depend on the size of the holes in the mesh. If they are bigger than 5mm or so then the dish will not be very efficient in Ku band. Smaller than that and it should work, if you can get an LNB that fits the mounting.
Wrong - the "hight" of KU bank is max 2cm and the holes would need to be larger that 1/2 wavelenght (1cm) for the dish not to reflect the signal back to the feed horn. No problem using an offset feed LNB and you can work out the focal point to place the LNB by Diameter x Diameter divided by 16 x the depth.
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Old 15-01-2006, 17:24
SteveMcK
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Originally Posted by eureka
Wrong - the "hight" of KU bank is max 2cm and the holes would need to be larger that 1/2 wavelenght (1cm) for the dish not to reflect the signal back to the feed horn. No problem using an offset feed LNB and you can work out the focal point to place the LNB by Diameter x Diameter divided by 16 x the depth.
I didn't say it wouldn't work, I said it would be less efficient. You also need to take into account the shape of the dish, and how closely it follows a true parabola. If you have imperfections more than 10% or so of wavelength you'll begin to lose the clean focus that you need. For Ku band, with 3cm wavelength, 3mm accuracy is what you need, hence my comment abiut 5mm mesh.

Anything up to 1.5cm will work, just not as well as a solid or fine mesh dish.
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Old 15-01-2006, 21:08
Bignick
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These mesh dishes are far more inefficent than their solid equivilents on the Ku band, they really are more suited to C band stuff. I wouldn't expect this dish to perform any better than a 1.8m solid!

Out here in Cyprus they have all but given up on them

Originally Posted by jimmyboy32
My friend has an old C-Band dish. I'm sure its 3m anyway and made of a meshy type material with an arm coming out the middle of the dish for an lnb.

Would it be possible to convert this for use with KU Band?

Its the spit off this dish?
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