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Omnidirectional Cantenna Array

A "Bloomin' Onion" of Homemade 802.11 Microwave Antennas
  (+8, -3)
(+8, -3)
  [vote for,

Posit: I want to drive around and try to access other people's Wireless Networks for fun and/or profit.

Posit: I don't want to spend any more money than absolutely necessary in increasing my laptop's receptivity to wireless signal.

Posit: It is insanely easy to make a directional wireless 802.11 antenna that significantly increases gain. [link] It is not so easy to create an effective omnidirectional wireless antenna.

Those being said, my idea is for a collection of cans on a mast pointing out in all directions, so, from above, it looks like this: *

Each of the leads from the individual cans would be spliced together and fed into the input of the wireless card.

contracts, Feb 04 2005

Cantenna Array ~bz
[bristolz, Feb 04 2005, last modified Jun 28 2005]

Homebrew Antenna Shoot-out http://www.turnpoin...t/wireless/has.html
Pictures and performance data for a variety of homemade microwave antennas. [contracts, Feb 04 2005]

Anemometer http://www.leslietr...ence/anemometer.gif
maintaining the homemade aesthetic [calum, Feb 04 2005]

Belkin 802.11G F5D7050 Adapter http://catalog.belk...&Product_Id=179211#
As mentioned by JungFrankenstein [contracts, Feb 04 2005]

Diversity antennae use in 802.11b http://mars.bell-la...pers/borst_whiting/
[csea, Feb 07 2005]


       I like the pic in the link, they've black'd his eyes out.   

       The danger of antennas ?
skinflaps, Feb 04 2005

       If modelled on an anemometer, the array, when in motion, could be used to generate power to your laptop.
calum, Feb 04 2005

       Surely a unidirectional aerial gains signal strength at the expense of directional coverage. How are you going to get the directional coverage back without sacrificing the signal strength?
st3f, Feb 04 2005

       "Tra-la La-la-la-la
Tra-la La-la-la-la
Tra-la La-la-la-la
[Doing the can can]
normzone, Feb 04 2005

       It would look nearly identical to [calum]'s linked Anemometer, except instead of pointing in that swastika configuration, they would radiate out from the center . . . like an asterisk.   

       [st3f], I'm not an EE, so I'm taking some half-baked liberties. I believe that this would be a happy medium between an expensive and complex true-omnidirectional antenna, and a sole unidirectional unit.   

       If I were a smarter man I would incorporate/describe a system with something similar to an automotive distributor cap that samples the signal strength from each unidirectional element at fixed intervals and provides throughput for the sole unit with the highest signal strength.
Unfortunately, I am not a smarter man. :-)
contracts, Feb 04 2005

       I monkeyed around with various cantennas for weeks. Finally tried the chinese wok with twenty dollar d-link 802.11b dwl-122 (there are off brands on the net for as little as ten bucks). Measure the diameter of the wok and square it. Divide that by the depth X 16 of the wok and presto - mount the antenna end of the adapter (for my wok it was 8.75cm) out from the center. Wow! Kinda cumbersome compared to the cantenna, but many, many times more gain. I just saw a Belkin 802.11G F5D7050 adapter on sale at Home Depot for 39.99.   

       Warwalking? Just hide it hunchback style under your coat. Directionality? Spin loopy circles down the sidewalk. Grunt and bark maniacally if you want to be left alone.
JungFrankenstein, Feb 04 2005

       [Jung]; so you used the wok as a parabolic dish like a satellite dish? Do either of the models you cite have a line-in for antenna or were you just trying to get a stronger ambient signal near the adapter?
contracts, Feb 04 2005

       oh yea - sorry. Unfortunately there aren't many cards or adapters with line-in, or it would make it easier. The little usb wifi "clip" is actually mounted in the dish and connected by a 10 foot usb cable. No signal loss with usb instead of coax so it's not a bad trade off anyway.   

       Somebody really ought to get a baking/wok connection going here to rescue this idea from its downward spiral into earnestness. I'm not up to it i guess.
JungFrankenstein, Feb 04 2005

       Oh! Great idea :-) I'll have to modify my approach - - I could do this with one hub and a single USB line out from the array, no splicing required, and have a seperate signal from each adapter.   

       A creative coder could probably design an app that performs the "distributor cap" function automagically.   

       Awesome drawing, [bris]. That's almost exactly what I had envisaged; Thanks :-)
contracts, Feb 04 2005

       [contracts], you're on the right track, but I'm fairly sure [contracts]' "distributor cap" notion (usually called "diversity") will be necessary, or the multiplicity of cans will sum to be no more effective than a single element omni pattern.   

       Hmm, a bit of googling, with more bleak outlook... see [link.]
csea, Feb 07 2005

       Hey, I'm just the dumb illustrator.
bristolz, Feb 07 2005

       I never expected to see [bristolz] and "dumb" in the same paragraph, let alone in a self-referential sentence!   

       Attribution removed from my previous annotation to deflect all the glory to [contracts!] ;)
csea, Feb 07 2005


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