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New Wi-Fi Distance Record Set In Utah
cold_sake writes "Wireless guru Rob Flickenger details the known records for Wi-Fi link distances on his latest blog. Included is a new distance record for an un-amplified Wi-Fi link, set by the students of Utah's Weber State University. 82 miles was accomplished with 802.11b."
In other news, new cases of cancer have appeared all over the Weber State University campus.
Seems amazing especially because of the close by mountain range.
Now can someone explain to me why I have such difficulty connecting to their wireless network while I'm on campus?
YOU'RE WINNER !
Another lame blog
A new distance record for an un-amplified Wi-Fi link, set by the students of Utah's Weber State University. 82 miles was accomplished with 802.11b.
Sources within Utah's Weber State University state that this amazing feat was accomplished with the aid of an 82 mile long antenna, laid horizontally along the ground toward the Wi-Fi node.
(Yes, dammit, I didn't read the article...)
They set up one wireless access point with the SSID set to the default 'Linksys'.
And many, many miles away they turned on their windows machine, and voila! There it was, the WAP with the SSID 'Linksys', wide open just as they had left it!
The Internet is generally stupid
The 802.11b MAC layer is fairly sensitive to timing latency. (I go into more detail on this article on timing in long 802.11 links)
Did they use the old ad-hoc demo peer to peer mode, which has no ACK's and performs much better over longer links?
Cisco cards are also well known for their quality; perhaps the cisco MAC can adapt to high latency long shots while also working well in infrastructure mode.
Does anyone have more details on exactly how tenuous this link was, and how they pulled it (card settings, cables, antennas?)
As a side note, myself and some others have been wondering how we might go about discerning the exact timing characteristics of different 802.11 MAC implementations using non-exotic hardware (like regular cards in monitor mode).
When you need to measure microseconds (or fractions of them) it gets tricky...
Weber State is famous for having launched its own satellite, Webersat, one of the OSCAR series. These kids are really at home with UHF and microwave radios!
In practical terms, the range of a microwave link, such as 2.4 GHz, is based on having line of sight without attenuation. The radio line of sight path is based on the horizon, with a simple guideline of roughly horizon (miles) = 1.4 * sqrt(height-in-feet). So if you have totally flat ground and 100-foot towers, your range to the horizon is 14 miles. The range of a hop is the sum of both sides' horizons. Now if you have a 2500-foot-high mountain to stand on, then your horizon is stretched to 70 miles.
The path loss is a function of distance, which antenna gain can make up for. The legality of doing this with unlicensed WiFi is a different question. Ham radio operators do this stuff routinely, but ham power limits are much higher, and there's no ERP limit. The 10 GHz band in particular is said to be popular in England. The crowded 144 and 430 MHz bands respond to similar rules. Attenuation by moisture in the air (serious form: rain fade) can get in the way, though. So if you're really looking for good distance, a nice place might be, oh, the Utah desert. Flat and no humidity.
So while it's possible to hack a good range with enough effort, conventional WiFi equipment is still not reliable getting from one side of my house to the other. It's really not a threat to the phone companies, especially in non-rural areas.
Actually I've been following these experiments.
They bounced the signal off Darl McBride's head, and the resulting distortion caused a rip in the fabric of space-time. That's why some reports have 72 miles and others 83. There was some heavy magnetomoronic craniorectal inversion in the signal.
This is similar to wind-aided records in track and field, and so the methods will have to be retested after Darl returns to his home planet.
sigs, as if you care.
Equipment List:
0 Inform ation.htm
0 Learned .htm
2- Primestar Satellite Dishes with modified feedhorns
2- Laptop computers with 350 Cisco wireless cards
2- Bidirectional Amplifiers (1.5 watt)
Compass & GPS
Tripods
Cables and wires - MMCX RT ANG male to N Male on RG174, 72".
http://classes.weber.edu/wireless/Project%2
They also stated they weren't sure of FCC regulations in the Lessons Learned page.
http://classes.weber.edu/wireless/Lesson%2
FCC Regs state that the maximum power level for unlicensed devices in the 2.4 GHz range are:
Field Strength of Fundamental (millivolts/meter) - 50
Field strength of fundamental frequency harmonics (microvolts/meter) - 500
See http://www.hallikainen.com/FccRules/2002/15/249/
In other words, it's cool, but it's illegal.
If you read the actual blog entry, Rob refers to the actual record of 310 km (192 miles) by a Swedish team.
Man, I know this is slashdot and no one reads the articles, but you thing the editors would once in a while.