Antennas and Electronics

Want to tinker with antennas?


I highly recommend you read this:

Introduction To Basic Electronics Hands-on Mini Course

Cantenna Report Update

I have been using my homebrew pringles cantenna for a little over 6 months connected primarily to a laptop in our workout room. We use it to keep health journas etc... so it only gets used a few nights per week, connecting to an access point a half block away, between which are a few trees, a pine tree, a raspberry and cherry tree, an ash, a 4 foot high iron fence lined with shrubs and across the street a 6 foot high concrete wall, behind that is the access point.

The connection varies little from 61% to 69%, during storms it is at 61% and is barely strong enough to load a google start page, at 69% the connection is strong enough to watch streaming videos at 480p, the performance is almost equal to a setup I had on the same computer with two windsurfers on a stock alfa wireless card.

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Linked To McDonalds Wifi From A Quarter Mile Away

Homebrew Yagi connected to Alfa wireless adapter was able to connect to a wifi hotspota quarter mile away. Next up: Cantenna!

How To Make Your USB Wireless Adapter 'Stronger'

To get the most out of your Alfa awus036h wireless adapter-open your terminal and type the following:

ifconfig wlan0 down
iw reg set BO
ifconfig wlan0 up
iwconfig wlan0 channel 13
iwconfig wlan0 txpower 30


*Change wlan0 to what ever your wireless adapter may be designated. i.e. wlan1
**Disclaimer: This may be illegal in your country.


Wifi Cantenna DIY


http://en.wikipedia.org/wiki/File:Coke-cantenna-SV1ML-0a.jpg
Q: What is a "Cantenna"?
A: A Cantenna is technically an open ended wave guide. That means the can or hollow metal tube is excited, by the coaxial cable, to radiate electro-magnetic energy. The diameter of the can or tube should be  according to the frequency you are working with. The length and the diameter of the can will determine the radiation pattern - excite the tube with the coax and that is all that's needed to receive and transmit.

Q: Why should I want to make my own Wifi Cantenna?
A: It's high gain, useful for connecting to faraway hotspots.
Not to mention it is a very useful antenna for war-driving, picking up a very respectable signal, a comparable antenna online would run you upwards of sixty bucks.
It's fun to build shit.

Q: What size can or metal tube do I need to use?
A: Quick answer - to work at 2.4GHz the cans diameter must be larger than 2.87"

 

 

Can Diameter

Cuttoff Frequency in MHz for TE11 mode MHz
Cuttoff Frequency in Mhz for TM01 mode MHz
Guide Wavelength in Inches inches
1/4 Guide Wavelength inches
3/4 Guide Wavelength inches

Yagi DIY

 Tools Needed For This Project

  • Wood Dowel
  • Wire - Household Copper Wire is Fine.
  • Drill or Drill Press
  • Pencil or Marker
  • Calipers to Measure in MM
  • Soldering Gun, Solder, and Basic Soldering Skills