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I want my wireless LAN to be available in an apartment that is 459 feet (140 m) across. I'm thinking about putting a router (bridge) that has an omnidirectional antenna on the roof of my apartment, somehow reflecting the signal from the antenna (making it directional) and pointing it (AS ACCURATELY AS POSSIBLE) at a Wi-Fi USB stick put on the roof of the other apartment. The stick would obviously be connected with a computer below with a USB cable and have some sort of means of reflecting the radio signal as well.

I'm seriously thinking about using this http://www.garneczki.pl/media/img/products/kpbig_70cd79520389c4303cd639c80bf65f.jpg as a dish (yeah, I know, it's a ghetto project but I want it either cheap or not at all).

Is it worth a shot? Is the half-spherical shape a good choice (mind you, I want the beam narrowly focused)? Is my project doomed to a failure?

The diameter of the hi tech "dish" I'm planning on using is 7 inches (18 cm) and it's made of "stainless steel". Sorry if this is a stupid idea and I'm wasting your time. Just let me know why.

Thank you.

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  • \$\begingroup\$ On an apartment building and/or in a ghetto, you want to be as inconspicuous as possible. Many buildings have satellite TV dishes cluttering roofs and patios. If you were to repurpose one, you may not attract extra attention to your project. Aside from that, it's a directional antenna. \$\endgroup\$ Commented Nov 20, 2013 at 1:07

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As others have pointed out, a waveguide antenna made from a metal or metal-lined can maybe your best bet. The advantage here is that someone has already figured out all the dimensions making your job a lot easier.

To answer your question, the optimal shape of the dish is a parabola, but a sphere is a decent approximation. When constructed properly, these antennas usually perform better than waveguide antennas. However, to design one you either need a very expensive full wave simulator or even more expensive RF test equipment. Also, the dish should be at least 5 wavelength in diameter to work well (which is about 65 cm)

By placing a reflector right behind your omni antenna you will change the impedance match on that antenna which may lead to even worse performance than before.

As to the options, I would either go with a can antenna from one of those sites or buy a cheap Yagi-Uda antenna on Ebay. These antennas have a small wind cross section and have a relatively high gain (~12 dBi)

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It's cheapiness make it worth the shot. Hours of fun for little money.

Also the cantennas seem to work well:

http://www.turnpoint.net/wireless/cantennahowto.html

Maybe, the stick signal is too weak. There's also the problem of carry the USB signal from the roof to the apartment. The maximum cable length for USB 2.0 it's about 5 meters according the standard.

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May as well have a look at the 802.11b Homebrew WiFi Antenna Shootout. A waveguide made from a beef stew can was the winner and beat some commercial "range extender" antennas by 6dB!

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