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Tuesday, August 27, 2002

A few words about building your own wireless access point or router....

What i've found out about 200mW 802.11b cards...
[netgate] offers a 200mW card for $90 - best deal there is, period. At defcon this card was being used with a homebuilt AP by a vendor and I got a fairly good look at it. There are 2 versions: one with no built in antenna but with 2 mmcx jacks for external antennas (ideal for your own AP) and one with a built in antenna and no jacks. Netgate also has a 100mW card for $65. I should be getting mine (200mW, no antenna) within a few days.
[demarctech] offers an interesting 180mW card that has a unique antenna arrangement: a flat antenna like most cards that detaches to reveal a pair of mmcx jacks. Their card runs for $150
[mikrotik] offers a 200mW card of their own manufacture for about $125. They also offer some other goodies for your own AP, be sure to check them out (though they are in Latvia, they seem to be fairly reputable)
[zcomax] and [sendao] both have 200mW cards that will be available "real soon".

If I didn't have the Sparc Classic and sbus->pcmcia adapter available to me, I would probably go with something like [this], a single board Pentium system with PCMCIA slots. You could also easily use a PCMCIA card with a PCI adapter in a [cheap PC clone], but it would take up a bit more space than the single board solution or the sparc. Computer Geeks has quite a few [cheapo peecees]. You shouldn't need anything faster than 100mHz really.
What you *do* need is a good antenna. Having that 200mW card sit there with a crappy antenna would just be a shame, like getting the world's best stereo system and wall-mart speakers. For some odd reason most of the antennas out there right now are directional, rather than omnidirectional. If you see an antenna with some outrageous dBi rating, chances are it's directional. You most likely want an omnidirectional antenna that covers a full 360 degrees. The highest dBi I've seen for far for those is 10dBi, with most being 5 to 8. Here are some sources for reasonably cheap omnidirectional antennas:
[signull] [their ebay auctions]
[hyperlinktech] (note they also have all the pigtails you could want- the cables that would go from your card to the antenna)
[netnimble] (note - netnimble offers an omni with your choice of connectors, which would save you $20-$25 for a pigtail to your card!)

Me, I am probably going to get a signull 8db omni and a pigtail from hyperlinktech. It costs a tad more than the combo offered by netnimble, but it's easier to swap antennas later, etc.
signull's site has a nifty open air range calculator that should give you some idea of what to expect with different components - you can get an idea of the increased range of an 8dbi antenna vs. a 5dbi, for example (I found it to be worth the extra $30 or so!)

8/27/2002 05:37:00 PM ] [  0 comments  ]
A good quick laugh