The Deliverator – Wannabee

So open minded, my thoughts fell out…

Super Cheap 802.11a Access Points

Posted by Deliverator on January 24th, 2006

802.11a is a wireless standard that hasn’t made as much of a splash as 802.11b & g gear. The 5 ghz band that the 11a standard uses has much less penetrating power than the 2.4 ghz that b/g equipment uses. Buildings love to eat .11a signals, requiring great number of access points to be deployed to cover a given area than with b/g gear. As such, 11a gear hasn’t caught on to as great an extent and is now available cheap through many surplus outlets. Given 11a’s inability to break out of a paper bag, why would you want it, even if it is available cheap?

There are a couple of good reasons, in my mind. For one, 11a gear is just as fast as g gear. Two, 11a gear uses frequencies that are not as heavily used as the 2.4 ghz band that is used by cordless phones, security cams and wifi gear. It is getting awefully hard to find free unlicensed spectrum in urban environments. I have personally been in places where my carputer has been able to see 30+ wireless networks simultaneously. That is a hell of a noise floor! Thirdly, because 11a gear uses such high frequencies, the wavelengths used are correspondingly shorter than b gear. That means you can create much smaller, high gain directional antennas. 11a gear might not be such a bad idea when you need to establish a high bandwidth connection in an noisy urban environment.

At last week’s Hacknight, Joe Towner brought in some corporate quality 802.11a access points made by Intel. He bought them for $4 each from surpluscomputers.com. I purchased three to play around with using my Jornada and internet access courtesy of t-mobile. Half the guys there were running packet sniffers and Ken was feeling particularly hacktastic after just getting back from Shmoocon (of which he is an organizer), so I wasn’t about to trust my credit card number to the unsecured wireless network at RedLine. Of course Ken just went to work for t-mobile (doing network security), where he will hopefully help close a few of their gapping security holes, so he could probably sniff my data anyways.

The access points arrived today, which was rather quick for such cheap shipping. I have been playing with it this evening. Initial thoughts:

  • Cool = software selectable antenna pattern (omni or 180 degree sector)
  • Not soo hot = need tftp server to flash the firmware. I used a free one from the aptly named weird solutions.
  • Cool = Has two mini-pci slots inside. One is filled by an Atheros mini-pci 802.11a card. The other can optionally be filled with an 11b card to turn the access point into dual mode ap.
  • Cool = Early reports show a high potential for hackability. The device has 16 MB ram and 8 MB of flash and a Motorola processor of some sort.
  • Not so much = kinda funny shape for an AP. Indicator lights unlabeled.