Antenna types

[Yournet@hotmail.com]

Try a home-brew 'compound waveguide cantenna' - the most forgiving approach is to use a USB device entirely or just the antenna inside the narrow element of the compound cantenna.

A 'compound cantenna' is something I have used for over two years with great success: as the name implies, it uses a compound waveguide approach.  This consists of two wave guides, a larger diameter waveguide provides a wider angle so it is less directional, finicky to set up.  It could cause more interference in congested areas similar to any wider angle antenna. The second waveguide antenna it fitted to a depth inside an opening cut in the back end of the first that is 1/4 wavelength measurement using the cantenna formulas.
http://www.turnpoint.net/wireless/cantennahowto.html

This arrangement provides about another 3 db gain over a typical single waveguide cantenna but perhaps the more significant benefit is the wider diameter of the capture antenna opening.  The second waveguide concentrates the signal further than a single large diameter waveguide can.  This also works with the conventional lossy coax pickup assembly,

Robert Syputa
206-367-6931
  ----- Original Message ----- 
  From: Tom Hayward 
  To: SeattleWireless Talk List 
  Sent: Tuesday, May 01, 2007 10:53 AM
  Subject: Re: Antenna types


  I've never tried a commercial cantenna, but it was quite hard to get a homebrew cantenna tuned and matched properly. I used an oversize tin (steel) can. It happened to be a slightly incorrect dimension to properly match to 50 ohm (understandable, it's designed for storing food). I hooked it up to a network analyzer and stuffed polyethylene in the can until it came up to 50 ohm--not easy to do without the network analyzer. If I were to do it again and didn't have the test equipment available, I would just buy one (a cantenna). 

  Dishes and yagis are nice, but big. I haven't used a panel, but they seem bulky for walking/driving with too.

  Tom


  On 4/29/07, Lucio Crusca <lucio at sulweb.org> wrote:
    Hi everybody, 

    I'm new here, I'm new to wardriving, I'm not even from Seattle (I'm from
    Italy). So please be patient with my newbie questions...

    I'd like to purchase some hardware to do wardriving (warwalking, etc...) 
    this summer. I plan to buy a 2511CD+ext2, a 7dBi omni directional antenna
    and a directional antenna. For the omnidirectional I guess there isn't much
    to say, they are all more or less the same except for their power, right? 
    The directional antenna is what puzzles me... which type should I buy? Bare
    cantenna? Yagi? Panel? Will a home built cantenna perform just like a
    bought one? Will a 20dBi yagi outperform a 15dBi cantenna by 33% longer 
    range?

    TIA for any advice.

    Lucio.

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