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Re: Dish surface 'flatness'



I believe you should be looking at no bumps, holes etc of more than one tenth (1/10) of a wavelength.
Obviously better than that will benefit performance.

Peter Ellis wrote:
> I am now the proud owner of a very 'second-hand' 3m mesh-covered 
> skeleton dish.
> 
> The mesh covering is metaphorical, rather than actual. I watched the 
> dish on its back while as a group of small children rolled the dish back 
> and forth and trampled holes in the mesh. That's the reason I was able 
> to ask for it. "Please take it away," was the manager's reply to my query.
> 
> Now, I need to re-mesh the dish, but I need to decide what 'flatness' 
> ('true-ness') the surface should be. There has to be a formula, that 
> encompasses things like: frequency of operation, curvature or focus 
> distance, etc.
> 
> I've done some looking online, but can't find it readily.
> 
> Suggestions, and discussion, please?
> 
> Please note: If you're going to also make product, brand name, or 
> supplier suggestions, then be generic as suppliers and products in VK 
> (Australia) will differ from where most list members will be sited.
> 
> With thanks,
> Peter
> VK1KEP
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-- 
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
Nigel A. Gunn. G8IFF   W8IFF (was KC8NHF)
1865 El Camino Drive, Xenia, OH 45385-1115, USA   937 825 5032
e-mail nigel@ngunn.net             www  http://www.ngunn.net
Member of  ARRL, GQRP #11396, QRPARCI #11644, SOC #548,  Flying Pig #385,
                   Dayton ARA #2128,  AMSAT-NA   LM-1691,  AMSAT-UK, MKARS,  ALC
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
_______________________________________________
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