DEFCON WiFI Shootout 2005

Congratulations to Team iFiber Redwire for their 125 mile unamplified 802.11b link!

       

 

This was accomplished with a 12 foot dish on a mountain on the outside of Las Vegas and their remote station with a 10 foot dish on a mountain to the west of St. George Utah.

The team had spent much of their summer break from University to build and test their equipment. With surplus satellite dishes scrounged from their home area, building a custom trailer for the remote station, assembling all the scaffolding for the base station and testing. The teams talents in welding, mathematics, electronics, ham radio, programming, and Linux were all necessary to break their previous record.

I went up for the afternoon on Friday the 29th and Saturday the 30th, 2005 to watch these masters of technology.

Lightning was common in all directions during setup on Friday July 29th:

 

Two way voice communications over the 100 plus miles was made nearly effortless with the use of 2 meter ham radio gear.

A view in the aimed direction of the base antenna (over Las Vegas)

 

Topography of 124.9 mile WiFi link.

 

Path of 124.9 mile WiFi link showing the mountain height overcoming the Earth's curvature.

 

The only time they tried the amps was when the remote group was on a mountain in Utah 143 miles away but could not quite reach the desired coordinates 2 miles further and hundreds of feet higher, the road ended and the terrain was too rough to continue driving. They were a little too low in elevation, with a small mountain peak obstructing the two locations, they tried unamplified and amplified, and the 802.11b link would not work.

If they made it to the desired location, I'm confident that they would have successfully linked up at 145 miles.

The three images above created with Radio Mobile. My Radio Mobile presentation at SOCALWUG and the video.

 

Hand crafted antenna feed with circular polarization (can you say AO-40). Connected to Z-Com XI-325HP+ 300mw PCMCIA cards in laptops running Linux.

 

 

 

Frequently Asked Questions:

What on earth do they need an amp for??

No amp was used in the 125 mile link. They tested the amps for about 10 minutes when the remote group was 143 miles away and this link did not work. Unfortunately the terrain would not cooperate. They had the amp on loan from a vendor. Also, the Z-Com PCMCIA card in Nevada was set to 300mw and the Z-Com PCMCIA card in Utah was set to 30mw.

Its just not fair that they called it "reliable", since they're blowing several retransmissions on every attempted send, so many, that I'm surprised the link works.

They deemed it "reliable" since it their applications, ssh to each other's Linux laptop, VNC etc. were up and running uninterrupted for several hours while they waited for the judges to arrive.

I can't even get my WiFI signal to reach my bedroom.

Install a 10' dish in your home :-)  You don't have Line Of Sight in your home nor do you have high quality antennas on your AP or laptop. Both of these factors may keep your signal from reaching you.

Isn't this too much power for WiFi?

All the members of the team are licensed Amateur Radio operators which allows much higher power.

Related Sites:

Main contest website:
http://www.wifi-shootout.com

PCMCIA cards used for each end of the link:
http://wlanparts.com/product/XI-325HPPLUS

Mike Outmesguine, author of WiFi Toys:
http://www.wifi-toys.com/wi-fi.php?a=articles&id=91

Winning team, iFiber/Redwire website:
http://www.wifiworldrecord.com

DEFCON:
http://www.defcon.org

Humphrey Cheung's Excellent writeup:
http://www.tomshardware.com/hardnews/20050802_103659.html

Xeni Jardin's blog:
http://www.boingboing.net/2005/07/31/defcon_wifi_shootout.html

Slashdot:
http://hardware.slashdot.org/article.pl?sid=05/08/01/1013218&tid=193&tid=1

SOCALWUG mailing list discussion of even results:
http://groups-beta.google.com/group/SOCALWUG/browse_thread/thread/e53e707a469f76ff/a18f6f0756d7d8df?lnk=st&q=socalwug+125+mile&rnum=1&hl=en#a18f6f0756d7d8df

Comments

[Landon]

How did you connect the dish to the PCMCIA card? Did the card have a place for the antenna, or did you have to solder, or something?

[Jeff]

One of the FAQ's asks if this is too much power. As it is stated (300mw = 300 milliwatts) no this is not too much power as this is actually a very small amount. Most handheld personal two-way radios can be operated without an FCC license using the FRS, Family Radio Service. The FRS requires that the radio broadcast at less than or equal to .5 watts or 500 mW. Now if someone mistyped and meant to put 300MW = 300 megawatts then yes this would be a large amount of power for someone with little training and no FCC authorization. I don't intend to suggest that the record holders have little training, just that if anyone else wanted to try this they should educate themselves first.

[unwire]

The PCMCIA cards used have a maximum power output of 300 milliwatts. During the contest, one side was set to 30 milliwatts, the other to 300 milliwatts.

[Bryan Fulkersin]

Where did you find Linux drivers for the Zcom cards? I just bought an XI-300HP, and am not able to get it working under linux. Wlan Expert only displays the output of this card at 100mw. How did you set yours to 300? (I know mine will only go to 200)

[Luis Quiróz Vera]

Dear friends:

I live in Perú's low jungle, where his climate is tropical, I dedicate myself to give oneself wireless's solutions. Which I have achieved at present my distance record to 38.5Kmts . utilizing 34dbi's antennae and 500mw's Acces Point mark Zcom mod. XI1500IB. But I have had inconveniences in transmission when I utilize or I demand but the data transmission resources while byline transference not have (subj) my ping it oscillates in 5ms to 10ms and if I hook but I increase PCs to 200ms - 4000ms and I arrive sometimes to get disconnected.
They have been able to With the experience than you want to toast to me(subj) any suggestion for the better my connection.

Attentively,

Luis Miyaxawani Quiróz Vera

[UK-WIFI]

NICE!!!
i've got standard USB WI-FI dongle and it only picks up 60% on my home network(encrypted+hardware firewall)stuck it to the front of a sat dish and point it at the window and now have 4 extra networks @ 50-60%.

[Jason]

I am looking to start a whole town wifi network I was wondering what kind of antennas i would need to do this

[mahendra kumar]

excellent

[hassan chehab]

dear sir:
i would like to know more about the product and if it works fine in an urban surrounding.

[Erik Wile]

In the US you can't transmit more than 20dBm Effective Radiated Power [ERP] which is only 100mW.
Licensed amateur radio operators can transmit legally at higher powers. And it's not just the card's power level, it's the sum of the cards power plus the antenna gain minus any cable losses.
I don't know what the antenna gains were, but it looks like they needed at least 50dB of antenna gain total, so say 25dB on each side... even on the "low power" side they were TX'ing 30mW [15dBm] so that puts them at about 40dBm ... 10Watts ERP! _Way_ above what unlicensed people are allowed to transmit. And if they had the same gain on the 300mW side that's up to 100W ERP... You could start to cook things in that beam. Do not try this in an urban setting or you might blind people!

[LVguy]

Wow dude, just link it up around the S.West for P2P and let see how good is that network
of yours

[John Olson]

Pursuant to US CFR-Title 47- part15.247 http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/47cfr15.247.pdf
at 2.4Ghz (802.11b/g digital modulation) you are limited to an output of 1watt or 30dbm with an antenna gain of no more than 6dB for a omni directional antenna 36dB = 4 Watts. For a point to point however (Same as this example) you may increase the gain of the antenna above 6dB. For every 1dB reduction in power you can increase 3dBi in antenna gain. (3 to 1 Rule)This will allow for up to 52dB per link side at 22dBm output power with an antenna with 30dBi gain without violating the Max power rules. This is for unlicensed usage. Safe exposure limits would indicate at least 6 feet away from the radiator to be within spec on an uncontrolled environment. http://n5xu.ece.utexas.edu/rfsafety/

I thought I would shed a light of truth to this discussion

[Jamie]

Cant you guys make a web page with instructions on how to build the masterpiece and put it on the market there are a lot of people that would want a long range wireless system similar to yours.

[John]

Jamie, duplicating this might not be all that useful. First, it is using amateur radio capabilities, so it can't be used for commercial purposes. Second, it seems like it might be overkill, and depends on getting those big dishes up high. That might be OK if you have mountains around, but in most of the US you would have to up very high on a commercial tower or skyscraper to go that distance - that will be very expensive ($1000s monthly).

You might research some of the commercial WISP (wireless ISP) gear, for example StarOS and Mikrotik. You could build a system using that gear that would go 10 to 30 miles for maybe $1000. You would still need line of sight, so some height is needed. The wlanparts.com website shown in some of the graphics above is a good source.

[abe jay philippines]

i have a hanzen parabolic antenna but idont know how to install the hardwares...

[Gihan Galagoda]

Thanks for the information.

[eric]

wooh! that's a challange .those many miles.I wish i was in that team.Any way what it all means is that parabolic dishes have a great gain and are better than any other antenna.Above 20 dB.so just forget about that expensive antenna and use that old dish at home.