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Antennas and wireless projects

Here we have a collection of projects and information that I have written up as a result of working with wireless networks. Unfortunately there seem to be no community wireless projects in London where I can put this knowledge to use, so I generally help abroad or do one-off wireless links.

Most of the information here concerns 802.11b/g networks. These are the networks which operate around 2.4GHz.

Some wireless information

Currently there are four wireless standards in widespread use: 802.11b, 802.11g, 802.11a, and 802.11n.

• 802.11b is the original wireless standard. It operated on 13 pre-set channels (see below) and provided a theoretical maximum bandwidth of 11Mbits/s
  
  These are the 13 channels available
  Channel 01 : 2.412 GHz
  Channel 02 : 2.417 GHz
  Channel 03 : 2.422 GHz
  Channel 04 : 2.427 GHz
  Channel 05 : 2.432 GHz
  Channel 06 : 2.437 GHz
  Channel 07 : 2.442 GHz
  Channel 08 : 2.447 GHz
  Channel 09 : 2.452 GHz
  Channel 10 : 2.457 GHz
  Channel 11 : 2.462 GHz
  Channel 12 : 2.467 GHz
  Channel 13 : 2.472 GHz
• 802.11g is what I like to call an update to 802.11b. It uses the same channels within the same frequency, but it uses a different form of modulation (OFDM) resulting in a theoretical maximum bitrate of 54Mb/s.
  Also because it uses the same frequencies, 802.11g is backwards compatible with 802.11b, requiring only a different form of modulation to use the b network. This is why most g cards are marketed as 802.11b/g cards.
  Also there is an extension (I know atheros chipsets have this) called "turbo-G" and from what I gather all it does is use two channels together to give you a maximum thoughput of 108Mbit/s
  The downside with 802.11g is that you get a shorter range than with 802.11b (at least, I have, with my experience)


• 802.11a provides 54Mbit/s but works in the 5GHz range. I don't know much else about this as I do not own a 802.11a card.

• 802.11n is a new standard that has a potential data rate of 600Mbits/s, theoretically enabling a user throughput (TCP/IP) of around 100Mbits/s in ideal conditions. Again, I don't know much else about this as I do not own a 802.11n card.