[kismac] Re: Cantenna_anyone using something like this?

  • From: GDevice@xxxxxxx
  • To: kismac@xxxxxxxxxxxxx
  • Date: Sun, 16 May 2004 13:45:27 EDT

Another good place to look is here...



In a message dated 5/15/04 4:10:47 PM, ray@xxxxxxxxx writes:
> > I had looked at various directional and gain antennas but soon realized
> > that at 2.4GHz the coax and connector losses are going to eat up most
> > of the gains unless you keep the coax real short.
> Don't waste $50 on something that would cost you less than $3 to build.  You
> can make a very respectable cantenna with a couple of soup cans and a
> connector.  Check this page for a nice illustration of one ...
> http://www.geocities.com/lincomatic/homebrewant.html
> The dimensions are important!  It should be 3.25 inches in diameter, and a
> little more than 7 inches long.  You can get away with connecting two cans
> bottom to top to form a nice long barrel (I held mine together with duct
> tape).
> Just about every one I have seen uses the N type connector (CD/Radio Antenna
> style).  Those connectors will run you five bucks, and for their size have
> lots of loss.  Also as Dan mentioned, the longer the cable, the more loss
> you will receive.  I decided to go with BNC connectors myself, and I ended
> up hacking apart a few wireless cards and adding a BNC connector to them.
> It also helps to have a crimper that will do BNC connectors.  I was able to
> make a 3 foot cable, BNC at both ends with solid (not stranded) copper core
> inside.
> With my cantenna, and a line of sight path (no obstructions) I can sniff
> signals from a full mile away (or more).  The signal you get with a cantenna
> can be deceiving, and it's hard to pinpoint exactly where it's coming from.
> Also, you usually cannot send signals as far as you can receive them.  In
> other words, you may be able to sniff traffic from an AP, yet not join the
> network.
> -Ray

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