# What is the best material and design for building a parabolic dish? [closed]

I'm currently using a homemade metallic spaghetti strainer with a wifi adapter inside it to increase my wifi adapter's signal reception, but would think that a different material, like the aluminum mesh used for the Arecibo Radio Telescope could be better?

Why is this radio telescope's reflector spherical and not parabolic?

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## closed as off-topic by Kyle Kanos, ACuriousMind, Sofia, JamalS, Qmechanic♦Feb 22 '15 at 9:43

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Hi Frank - what exactly are you asking here? Are you asking whether a different material would increase your signal reception more than your spaghetti strainer? Also, why did you link to that other question? – David Z Jun 25 '12 at 0:27
Looking for optimum: material, size, shape, pattern.. Linked to radio telescope posting as reference because that reflector is made of aluminum panels and its shape is spherical because it can't be moved. – Frank R. Jun 25 '12 at 2:03

## 2 Answers

The WiFi frequency range is pretty much the same as a standard microwave oven. The reflective coefficient of the metal mesh in the front door is above 99% and it contains no special materials.

On the other hand the shape of the reflector has a large influence. So either you can follow Martin's suggestion of a can antenna, which is widely used or buy a cheap satellite dish. Even a small 40cm dish should boost your signal by several orders of magnitude. Both ways only provide a narrowly focused signal cone so you have to optimize the alignment carefully.

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Wifi is around 2.4GHz so a wavelength of around 12.5cm Anything metal with holes much smaller than 12cm will work - even a mesh.

But if you don't have a parabolic dish, only a spherical one, you might do better with a can antennea see eg http://www.turnpoint.net/wireless/cantennahowto.html for details of the calculation

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