Wi-Fi Reflector

[WG1337]

Hi!
I read about adding a simple reflector to a router would improve the signal, if the signal needs to go in one direction.
So all I need to do is make a parabolic shape aluminum foil.
Then I tried to get the right dimensions of the shape, but couldn't figure out, so I downloaded a application "Parabolic Calculator 2.0", but still can't figure out what I need.
So I input, for example, 250mm diameter, depth as 50mm and 2462MHz as frequency.
As a result I get this:

f/D = 3.13
Focal Length = 7812.50 mm.
Illumination angle for feed = 18.3 degrees
Space attenuation = 0.06 dB 
Desired taper = 9.94 db for 10 dB edge illumination
A simple feed horn would have a diameter of 6.57 wavelengths for a 3 dB beamwidth of 10.05 degrees
Gain at 50% efficiency = 33.05 dBi

As far as I understood I need to get "Gain" bigger.
What number should I try to achieve?

 

[HiTech]

There are numerous designs and projects on the net depicting in detail on building a WiFi hi-gain antenna. Use your browser and enter High Gain WiFi Antenna. There are simple aluminum foil types to using a Dish TV dish for eeally high gain and directivity. The juice can and copper wire is one of the easiet ones to build.

 

[RMMM]

Cantenna.

I have built a few. I was SO supprised by the results, that they are a main stay in my toolbox.

 

[WG1337]

Lol, simply a tin can without the dish?
If I have 2 antennas (b/g router) then will it be ok if I only install this modern Cantenna to one of those antennas?
Btw, what distance gain did you get with this engineering miracle?
I was more interested on how it really work (the math behind it all), more then making it... wanted to understand which number tells me that I reflect more waves to the center.

 

[RMMM]

My first attempt resulted in a 3db gain.

My second increased almost 9db.

A friend has a few acres of land and has a barn/building in about 180ft from the home. We put the router antenna in the window of the home facing the barn, and the barn antenna in a front window.

We had great throughput and very little losses.

Aiming the cans a little better would have increased the throughput, and FOLLOWING THE directions and research DID increase cantenna results.

Length, diameter, and material all matter. Take a few minutes at the grocery store with a ruler or calipers to find the best can for the job.

My results were average for what the fellas on the linked page got. So if you follow the directions, you can easily have a great $5 antenna.

 

[Sceadwian]

It's not a simple tin can, the dimension of the can are important. A well designed can will give you 12db of direction gain with some sharp sidelobes of no critical importance for typical usage.
The cantenna has so much directional gain that you'll actually have to modify registry information on the PC's as good radio reception can be had at 2-4 times the distance that the standard wi-fi time of flight distance will time out at. Quiet often even with the use of a cantenna if more directionality is required a dish is used and the cantenna is the receiving element, just like a standard satelite dish, only much larger because of the relative frequencies.

 

[HiTech]

The modified Direct TV dishes are receiving signals as far as 1.5-3 miles optimum - pretty impressive and there's likely some dummy out there with an open WiFi signal to piggy off of!

 

[Sceadwian]

That depends on the transmitter/recevier HiTech, the ones that have gone that far have modified timings for the default packet re-transmissions. Over about 1 mile the time of flight is so long that a generic wi-fi transmiter will try to retransmit a packet which will cause spotty bandwidth and possible complete loss of signal as the tx/rx jams the signal in a race condition trying to find good ack/nacks. Also those long distance shots are all line of site.