An easy to add, external antenna connection for the compaq WL100 prism 2 based pcmcia wireless lan card.
http://www.frars.org.uk/cgi-bin/render.pl?pageid=1061
I started from one of the examples (70 cm, 12 elem) and scaled it to 2400 MHz as explained. I used 1.5 mm˛ domestic wire. I drilled small holes in the wood to put the wires in and I glued them in. One can see pieces of matches glued to fix the 'N' connector. I just used 8 elements for a first test .
http://seattlewireless.net/index.cgi/MicroTVAerial
Here is construction details for a simple but effective antenna for 2.45Ghz wireless lan use. This antenna is suitable for feeding a sky mini dish. It will give you a gain of around 10Dbi. Actual gain of course will be dependant of final tweaking of the antenna. Tested with a sky mini dish and has had a good contact over 6km.
http://www.frars.org.uk/cgi-bin/render.pl?pageid=1058
The aerial was derived from information on helical antennas in the ARRL Antenna book. The idea behind this aerial was for anyone to be able to make their own aerial for point to point links, and do it cheaply. You can even it with any other equipment that requires a broad bandwidth in the 2.425GHz band such as the new 802.11 wireless network cards or video transmitters.
http://www.wireless.org.au/~jhecker/helix/
This is a simple double-quad antenna built for 2.4GHz operation. This has been built and compared with his other antennas.
http://www.saunalahti.fi/elepal/antenna4.html
This antenna has been found about 2 dB better gain than the Freedom antenna, which is specified as 12 dBi antenna. Using 5 metres antenna cable there is no risk of exceeding the output power within the ETSI standard. It can also be built without the Ring to decrease antenna gain if needed especially with very short antenna cable.
http://www.saunalahti.fi/elepal/antenna1.html
Not everyone has measurement equipment for testing 2.4GHz antennas laying around. There are however some simple tests you can perform to establish if an antenna behaves as an antenna, or an elaborate air-cooled dummy-load. Here we make use of standard Radio LAN equipment to assess your homebrew antenna.
http://pe2er.nl/antennetesten/
The antenna is constucted only of a cylindrical can and a N connector with centre tap lengthened. Just point the open end of the can to the ISP station and begin surfing. Oh, of cource there is needed some cable between the antenna and wlan card.
http://www.saunalahti.fi/elepal/antenna2.html
The double quad is a simple to build but effective antenna for 2.45Ghz wireless lan or video sender use. The antenna can be matched to 50 ohms by adjusting the distance between the figure of 8 element and the backplane. In this case, the figure of 8 element is 17mm away from the backplane and this gives a good match.
http://www.frars.org.uk/cgi-bin/render.pl?pageid=1064
You also need a USB WiFi adaptor ! The largest (300mm diam)shows 15-18dB gain (enough for a LOS range extension to 3-5km), costs $5 and comes with a user friendly bamboo handle that suits WLAN fieldwork- if you can handle the curious stares!
http://www.usbwifi.orcon.net.nz/