I've been looking to make a linear parabolic reflector for Wi-Fi, I've found quite a few sources, such as:
I'd like to know a bit more theory, and the pros and cons of various parabolic shapes.
For a parabola to work at maximum theoretical gain (based on aperture size and feed efficiency), you have to be within about 1/10th of a wavelength accuracy. That's about +/- 1.25cm. You can build it much sloppier, but the achievable gain and pattern will suffer.
The feed is also critical as you don't want too wide a pattern resulting in "overspray" which reduces xmit gain, or too small a pattern that illuminates only part of the dish, resulting in low receive gain. I short, you need to match the feed type with the f/D ratio of the dish.
The best source of dish and feed info is at:
Simple A4 card covered in foil and bent in the middle at 60 deg. does a good job. Regards, Martin
Nigel
I would imagine the reflections of the signal follow the rules of optics if you look up optics on how to focus a light bulb, I would think that's how its done but its not necessary a parabolic reflector just convex in one plane ( half a tube) bear in mind light reflects off a mirror at the same angle as it hits form this you could work out what shape is ideal, but I dont think its that critical and its not rocket science.
Please don't get stroppy but who is Occam, by the way?
MikeS
See:
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