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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."
... If you ask me. 98 Dollars of crap you find at a Home Improvement store makes an antenna that blasts across as small desert.
Ingenuity++;
I take my hat off to these guys.
Edward@Tomato - /home/Edward/ man woman
man: no entry for woman in the manual.
"Qua!?"
Notice that the shape of the winning antenna is a pyramid? There are a lot of theories regarding electromagnetism and the pyramid shape, including a bunch on how the ancient egyptians figured out how to utilize these electromagnetic properties, which is (supposedly) why the pyramids were built that way.
If you want to get kooky, it can also point to the extra terrestrial origins of ancient egyptian civilization.
Why do I h8 apple?
> The antenna was built from metal poles, window screen mesh, cardboard, duct tape, and aluminum foil!
And the deep knowledge on how to put these materials together, how to calculate the parameters and how to trim the antenna to achieve the maximum adaptation to the transmitter/receiver.
Analog electronics is the art of adding 1 to 1 to get always a result near to 2 but never an exact 2, and microwaves follow this principle literally: one tenth of a millimeter error can make the difference from the best antenna and the worst one. These guys did a darn good job.
0.0001 mile is 6.3 inches (16 cm) -- I can believe they measured the distance to within that accuracy, probably using a laser.
Here's part of an interesting discussion by ham radio people on VHF and UHF antennas in an area (Santa Cruz mountains) where reception is terrible.
The conclusions I draw are:
1. crappy antennas with amplifiers can work esp. if the amp is right next to the antenna (but it does have to get power- the Fubas on VWs are too short, but amplified, but they switched from separate power to "phantom" power over the RF lead that's unreliable)
2. putting the antenna outside on a tall mast is better than indoors, but in an attic might be an OK compromise
3. directional beats omni, but you'll need a rotator, a "farm" of antennas (feasible when there are only 3 or 4 xmitter sites as in SCruz) or you need to live somewhere (the end of a long peninsula?) where all the transmitter antennas are in the same direction
4. some commercial antennas are poorly designed, but good ones (Winegard) aren't that expensive- $90 - $220.
5. there are good VHF antenna designs for the ham bands near the TV bands and software that'll calculate element lengths & performance if you put in the different frequency
6. the emphasis in antenna design seems to be in UHF these days because HDTV uses that band & the set owners are the people that need the reception & have the $$ for the antenna & installation.
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If I didn't have satellite, I'd build a farm of stacked dipoles on the roof for VHF and buy a couple bowtie + screen antennas for UHF. Rotators are pain in the ass because the wind can blow the antenna out of alignment so all of your channel/angle settings need to be re-jiggered. They're also expensive.
Check out http://www.adversarialsciencelab.net/sumdoo.html Sumdoo has some info on what happened to us... Did I mention that one of the other teams also was trying to jam us... sore losers!