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DefCon WiFi Shootout Winner Announced
devn2k writes "At the first annual WiFi Shootout at DefCon in Las Vegas, Adversarial Science Lab won the contest to shoot a wireless signal across the Nevada desert, with a distance of 35.2196 miles. The antenna was built from metal poles, window screen mesh, cardboard, duct tape, and aluminum foil! According to the official contest page, the antenna was designed the night before the contest, its component parts were purchased for $98 at Home Depot, and the next day it was built completely from scratch in the desert, on the side of the mountain, in the rain."
Alvarion is not Swedish (in fact, it's basically BreezeCom in new clothing), but the record was set with the help of SSC, the Swedish Space Corporation. Slashdot story link here.
Money for nothing, pix for free
Photo of anntena and team. Its look pretty cool.
-- ladies and gentlemen we are floating in space!
Impressive yes, but typical of what ham radio operators do all the time. (Many of the ASL team members are hams, as was mentioned in the story.) We're always building equipment out of such mundane stuff as tuna fish cans and coat hangers, and making contacts around the world.
Except the Pyramids were made of nonconducting sandstone and limestone, and were about as good antennas as say, a small mountain. I.e. they block electromagnetic waves rather than concentrating them. Now if the pyramids were made out of aluminum and duct tape, you may have had something.
I'm sure their success is attributed more to knowing what you are doing in a McGyver'ish way than simply hacking.
Yeah, antennas don't respond well to guesswork.
Most people don't know that an antenna rings electrically the way a tuning fork rings mechanically. There's only a very limited frequency range that an antenna will handle well.
On top of that, as the frequency increases, radio waves behave more and more like light. And problems like stray capacitance and stray inductance - tiny values in farads and henries - become very important design considerations as the frequency increases.
But a well-designed amateur antenna can be very capable. The radio waves don't care if you make the elements out of silver encrusted canine feces, if they're the right lengths.
UHF TV band, around 450MHz. Design is extremely critical here. But by doing a little math first, I designed and built a 12-element Yagi (looks like an ordinary rooftop TV antenna but with more elements) which is tuned to channel 29. It's very directional, meaning I have to be pointed within a few degrees of the transmitter. But I can also watch WUTV Fox 29 from Buffalo, in Ottawa Canada, without shelling out for cable. Cost? Scrap of wood, old coat hanger wire trimmed to within 1/16" of the design dimensions, plastic tubing and clips to hold the elements to the board, old 75-300 ohm matching transformer gutted for its balun and soldered directly to the driven elements and feeding coax. Essentially free. Not waterproof, so it lives in my attic.
Fire and Meat. Yummy.
It looks like 5G Wireless took the commercial category at the wifi shootout---14.8 mile coverage using their commercially available antenna. I'm not sure how widely known this is but Mcdonalds has a pilot in upstate NY according to this --feb 03 http://www.wirelessweek.com/index.asp?layout=artic le&articleid=CA274448
trades for a few pennies on the OTC bulletin board under FGWC
were any of these other wifi shootout companies public?
"CATEGORY 5 - Enhanced power, (omni or directional) commercially made antenna Base Camp GPS Coordinates: N36 39.698, W114 55.431 Field Site GPS Coordinates: N36 52.523, W114 57.389 At the base camp: Apple G4 800 MHz Notebook, with 10.2.6 ftpserver, 5G single panel AP, 3-foot tripod, 15-foot mast, angle ~150. At the field site: 4ms 4.26 Mbps, Toshiba Satellite 1135-s1552, P4M 2.0 GHz 512 meg ram, Windows XP Pro ftp command prompt only, 5G CPE 800 mW, 16 dbi circular polarity antenna, RSSI -67 dbm, Noise f