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Not only does he post outright lies about using a passive repeater in a really long wireless link, he didn't have the balls to admit that he was lying.

For cripe's sake, he even jumped on the Google bandwagon.

I've said it before and I'll say it again, take this gentleman's tech predictions with an extremely large grain of salt.

This is the man who brought us the mathematically impossible 6.5 mile 802.11 link with a passive repeater. The repeater that he never showed to anybody. He also shows us an idealistic world of a community cable and telephone company that nobody's ever seemed to find evidence of.

Saying that, when it comes to technology at least, he is speculative is something of an understatement. Take what he says with an extremely large grain of salt.

The FCC limits 802.11 power so buying expensive access points isn't going increase your range.

soekris boards, if you can afford them, have the advantage of "power over ethernet" and no moving parts, plus they fit nicely into a weather proof boxes so can be mounted high up. If you don't need these advantages any old sub $50 access points should work.

If you're really on a budget you can build your own.

Mostly, it's all about the antennas. In some experimetns I've read about, directional antennas have enabled signals to broadcast and receive across several kilometers (line of site). Check out these guys to see what's available as far as antennas go.

Also, sign up for the bay area wireless mailing list while you're building this. This is one of the better lists I've been on. There are some people that really know their stuff and you'll get lots of help and advice.

Hope that helps.

I am one of the people building SFLAN. Our map is a little outdated (and the San Bruno Mountain node is in the wrong spot). SFLAN and BAWRN have some 30 nodes in as many locations in San Francisco and a few outliers in surrounding counties. If you are in San Francisco and want to try it out, Cole Street is well covered. The SSIDs are sflanNN or BARWN-xxxxx; DHCP, no WEP.

The nodes are owned and paid for by individuals, many of whom are members of the Bay Area Wireless User Group. The Internet bandwidth for SFLAN is sponsored by the Internet Archive. If you live in SF and want to buy a node to connect your house and your neighbors, contact us.

We like to keep these networks as free (as in speech and beer) as possible. And it's working out so far. I hear Tim Pozar's neighbors keep him happy with occasional pies...

...and whilst that was a nice informative article, it was also noticeably linux specific (of course, you couldn't be trolling - not with a closing line like that).
This being the BSD area of /., I think a few BSD targetted articles on configuring WAPs
might be more apt.

That said, this WiFiBSD thing looks like a nice little development. Could well come in handy.

Here in State College, PA I usually eat at a locally owned coffee and bagel shop called Irvings or a large regional grocery chain called Wegmans. Both places offer free wifi, the local Starbucks doesn't even offer wifi and if it did you would need to pay ~$6/hr.. If two places are of equal quality, but one offers free access, where would you go?

The LocustWorld Meshbox site
Seattle Wireless
Bay Area Wireless Users Grou BAWUG
Kingsbridge Link Community Wireless Network
Consume.net
Meshnet, low cost nodes

http://www.nycwireless.net/ - lots of info on how to set up a secure, shared public access point
http://www.bawug.org/ - the most technically adept wireless user group. Their mailing list is worth its weight in gold.

Good luck.

San fransisco, Seattle, New York, Atlanta, Adelaide, Sydney, London, Rotterdam, And more

you know, here in san francisco, the attitude takes it even further into the public's hands. i am sitting at a (non-Starbucks) cafe at california and divisidero, and my PCMCIA 802.11b card sniffs not only the free WAP at the cafe proper, but also the chinese restaurant across the street, and the dude around the corner who not only makes his WAP available, but LET'S PEOPLE KNOW. And let's other people know. Pretty soon those people start talking,and even communicating in other ways.

The internet itself has been described as the great equalizer. Grassroots wireless networking has the potential to put one more bullet into the chest of inequality, and then the internet may begin to continue it's evolution from shitstream teevee/radio corporate fuckfest, to the greatest tool mankind has ever made. ...Then we throw out the dixie cup...

Tablet PCs are the natural evolution of the Ultraportable laptop, IMO.

I'm all for being able reach in my bag, resume from suspend-to-disk, load up mapquest and find that "pizza place in the neighborhood". The combination of wireless broadband and "slate-type" devices is part of my recurring "Geektopia Paradise" fantasies that I seen to be having all the time.

I, for one, have used my VAIO SuperSlim notebook(armed with our friend, 802.11b) to do everthing from "WarWalking" (scanning for wild 802's on foot) to ordering chinese food (all of this, without giving any money to Starbuck's).

Given the popularity of PDAs and Laptop PCs in our culture, I think that the tablet concept will be well-recieved by a pretty large cross-section of consumers, ranging from soccer moms (read a novel, order dinner, eMail the hubby...all on the sideline's of Junior's scrimmage match), to the hardest of the hardcore geek (dude, have you checked out my go-everywhere Linux tablet with built in camera and GPS module that updates my webcam AND coordinates?).

Just my .02

Rolling out a community network is a great idea and probably any network geek's dream. But DSL, oh my! Many wireless community networks have proved 802.11b is the perfect technology for this. These guys in Seattle are trying to cover the whole city and IMHO they're very likely to succeed.

So you want to roll out a network in a small city ? UseNoCat Auth for authentication, connect everything to the net, and already you'll be able to read slashdot while sitting in the middle of the street.

By Tim Pozar - pozar@lns.com
for the Bay Area Wireless User Group

1. Background
   1. Introduction

      With the unlicensed use of 802.11b radio Ethernet devices in the Industrial, Scientific and Medical band that has been set aside for such use, there is confusion of what is allowed or limited by the Federal Communication Commissions Rules and Regulations. This paper is meant to help guide folks through the cryptic nature of these rules.

      This paper does not cover other legal issues of using these devices such as FCC type-acceptance, Radio Frequency Radiation issues (ie. ANSI RFR levels) or Appropiate Use Policies (AUPs) of ISPs you may connect to.

   2. What is the FCC's involvement in this mess?

      The FCC is a regulation body whose purpose was defined in the Communications Act of 1934 as:

      "For the purpose of regulating interstate and foreign commerce in communication by wire and radio so as to make available, so far as possible, to all the people of the United States a rapid, efficient, Nation-wide, and world-wide wire and radio communication service with adequate facilities at reasonable charges, for the purpose of the national defense, for the purpose of promoting safety of life and property through the use of wire and radio communications, and for the purpose of securing a more effective execution of this policy by centralizing authority heretofore granted by law to several agencies and by granting additional authority with respect to interstate and foreign commerce in wire and radio communication, there is created a commission to be known as the "Federal Communications Commission", which shall be constituted as hereinafter provided, and which shall execute and enforce the provisions of this chapter."

      The FCC, with the Act of 1934, was empowered to regulate wire and wireless communications. Wired communications regulation was needed to monitor and regulate monopolies. Wireless regulation is needed as the spectrum is finite. The FCC is the "traffic cop" to ensure that communications is not interfered with.

2. Part 15 of the Rules and Regulations

   Almost every bit of spectrum is regulated by the FCC with the exception of extreamly high or low frequency spectrum and bands managed by the Intergovernmental Radio Advisory Committee (IRAC) for the military and other goverment orginizations, by licensing operators of radio equipment. The part of the FCC's rules that cover the operation of equipment that does not need a license is (3) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of this section, if transmitting antennas of directional gain greater than 6 dBi are used the peak output power from the intentional radiator shall be reduced below the stated values in paragraphs (b)(1) or (b)(2) of this section, as appropriate, by the amount in dB that the directional gain of the antenna exceeds 6 dBi.

   • (i) Systems operating in the 2400-2483.5 MHz band that are used exclusively for fixed, point-to-point operations may employ transmitting antennas with directional gain greater than 6 dBi provided the maximum peak output power of the intentional radiator is reduced by 1 dB for every 3 dB that the directional gain of the antenna exceeds 6 dBi."

3. Lets dissect this section...
   • Part 15.247(b)(1) defines the maximum power that an intentional radiator can put out as 1 watt.

   • Part 15.247(b)(2) doesn't apply as it is covering devices in the 902-928 MHz band and 802.11b devices are in the 2400-2483.5 MHz band.

   • Part 15.247(b)(3) covers the need for limiting the amount of radiation the "intentional radiator" can emit with "directional gain" antennas. It says that in general (with an exception coming up) that if the gain of the antenna system is more than 6 dBi, the intentional radiator needs to be turned down to keep the emission at the 1 watt maximum plus 6 dBi (36 dBm or 4 watts EIRP). The FCC encorages the use of directional antennas. With that they give you 6 dBi more power for not poluting the rest of your space with radiation that is not needed to do what you need to do.

   • Part 15.247(b)(3)(i) covers the need for limiting the amount of radiation the "intentional radiator" can emit running "fixed, point-to-point" with "directional gain" antennas. This means that the transmitter is mounted not on a moblie device and is talking to one other transmitter.

Do we need to turn down the transmitter?

1. Omni-directional or Point to Multi-point paths...

   15.247(b)(3) makes the assumption that you are running a point to multi-point network much like an Apple Airport or Cisco/Aironet AP box with a number of computers connecting to the network. They may be randomly surrounding the access point so you are not using a directional antenna.

   But what does the FCC mean when they limit the "intentional radiator" to one watt?

   This is a critical sticking point in understanding what the FCC is talking about. There is some question of what an "intentional radiator" consists of and what and where exactly is 1 watt measured. Unfortunatly if you just look at these poorly written rules you will not understand what the FCC means here. One has to look a bit deeper to the "Report and Order" and Notice of Proposed Rulemaking" that generated this section of the rules.

   Things get a little clearer when we read this sentence in paragraph 4 of the Report and Order...

   • "The current regulations limit spread spectrum systems to a maximum peak transmitter output power of one watt. When operating at that power level, the maximum directional gain of the associated antenna may not exceed 6 dBi, resulting in a maximum equivalent isotropically radiated power (EIRP) of four watts, i.e., 6 dBW."
   With the old rules they are refering to the "intentional radiator" as a whole with a directional antenna can't exceed 6 dBw or 36 dBm and the antenna gain can't be more than 6 dBI. The transmitter can be up to one watt.

   In order to know if we are legal or if we need to turn down the transmitter we need to know the gain of your "intentional radiator". Let's say your access point actually puts out 1 watt of power and you want to put an omni-directiona antenna on it that has a gain of 5 dBi such as the ORiNOCO Range Extender Antenna".

   We know the gain of the antenna, the transmitter but we also need to know the loss of the transmission line going to the antenna as this attenuats the transmitter output power going into the antenna. Looking up the attenuation of a common coax cable such as RG-8 on an coax attenuation table we find that at 2.4 GHz we have 16 dB of loss with 100 feet of cable. With a 10 foot cable your loss is about 1.6 dB. So your new "intentional radiator" will be radiating transmitter power output plus antenna gain minus coax loss or (30dBm + 5 dBi - 1.6 db) or 33.4 dBm or 2.2 watts EIRP.

   Since this is a non-directional antenna you are limited to 1 watt EIRP or 30 dBm. The transmitter will need to be turned down 3.4 dB to 26.6 dBm or about 0.45 watts (450 mW) to get you back to 30 dBm or 1 watt EIRP.

   If you think about this you may ask, "why add an omni-directional gain antenna it if I already was at 30 dBm?" You would be correct that it would be a waste of time. But if you had something like an Apple Airport that will only put out 15 dBm or 30 mW then you can add an omni-directional gain antenna and it will extend your "roaming" area. In fact you can add up to 15 dB of gain with an omni-directional antenna before you need to attenuate the output of the Wavelan card in the Airport.

2. Use a directional antenna and get more power - or - this is where the Rules get even more hard to follow...

   Part 15.247(b)(3) actually gives you a free 6 dBi if you use a directional antenna your "intentional radiator". How do the do this? Only if the gain of the antenna is over 6 dBi will the Feds want you to roll back the EIRP of your "intentional radiator". You don't have to do it right at 1 watt EIRP. When would you do this? Say if you have an access point in the corner of a building and it needs to aim back into the work area. You don't want an omni-directional antenna as about 75% of the power would be going out the windows. Why not use a directional to keep the signal in the building and penetrate through the walls better? If we have antenna gain of about 12 dBi and in this case the antenna is a directional antenna. With the transmitter putting out 30 dBm and the coax has 1.6 dB of loss we have an "intentional radiator" that is putting out (30 dBm + 12 dBi - 1.6 dB) or 40.4 dBm or just over 10 watts EIRP. Since the antenna gain is 12 dBi and we have to reduce the power of this "intentional radiator" 1 db for every db we go over 6 dBi of the antenna we would have to roll the power back to 34.4 dBm or 2.2 watts EIRP (40.4 dBm - (12 dBi - 6 dBi)). Well, it is slightly better than 30 dBm or 1 watt EIRP.

3. Fixed, point-to-point paths and get even more power...

   There is another exception to this section of the FCC rules. Part 15.247(b)(3)(i) covers systems that are "fixed, point-to-point". That means this path only has two transmitters involved and they are bolted down by never moving their locations. Automobiles may not apply. An example would be if you have an access point and a user that is a couple blocks or even tens of miles away that you want to connect to.

   This exception is more lenient as you only need to turn down the "intentional radiator" 1 dB for every 3 dB of signal over the 6 dBi of the antenna system. The FCC does this as it knows that these paths will not likely not be omni directional on each end and will have less of a chance to interfere with others as well as the need to span some long distances.

   Lets look at an example using the same antenna, transmission line and transmitter as above. Without turning anything down we had an "intentional radiator" that was producing 40 dBm or 10 watts EIRP. Since the antenna gain is 12 dBi and we have to reduce the power of this "intentional radiator" 1 db for every 3 db we go over 6 dBi of antenna gain we would have to roll the power back to 38.4 dBm or 7 watts EIRP (40.4 - (12 dBi - 6 dBi) / 3).

Real world examples...

1. Omnidirectional Point-to-Multi-point...

2. Directional Point-to-Multi-point...

3. Directional Fixed, Point-to-Point...

   Recently I put up a short path between myself and a neighbor about 2 blocks away (.2 miles). I have an Apple Airport that uses the Lucent Wavelan Silver card that puts out 30 mW or about 15 dBm. The antennas have a gain of 24 dBi with a transmission line loss of about 6 db. This gives me an "intentional radiator" power of 48 dBi. Since the antenna gain is 18 dBi over the 6 dBi that the FCC gives you and since it is a fixed, point-to-point link I would have to limit my

   [...]

   Since the little Wavelan card only puts out 15 dBm, I am legal as far as part 15.247 goes.

Quicky Definitions...

1. deciBels - dB

   dB, or one tenth of a Bel, is a unit of mesurment that looks at the ratio of one value to another. Gain or loss can be measured in dB. The dB scale is an exponential scale using the formula log(ratio)*10. This means that 3 dB is about twice the power, 10 dB is 10 times the power, 13 dB is about 20 times the power and 20 dB is 100 times the power.

2. dBm

   dBm is deciBels referenced to a value of 1 miliWatt of power. Power over or under 1mW would be plus or minus dBm respectively.

   If you have a transmitter that produces 1 watt of power that would be 1000 times more than 1 mW so that converts to 30 dBm.

3. dBW

   dBW is deciBels referenced to a value of 1 Watt of power. Power over or under 1 Watt would be plus or minus dBW respectively.

4. Effective Isotropic Radiated Power - EIRP

   Effective Isotropic Radiated Power defines the gain of an antenna over an "isotropic antenna" that would radiate equally in all directions.

   An example would be a light bulb. A lightbulb is designed to radiate light equally well in all directions, except the direction that the base is in.

   If you have an antenna that radiates better in one direction than another, it would likely have gain in this direction. The amount of gain would be shown as "dBi" or dB gain (or loss) over an "isotropic antenna".

   To further our example above, if we have a light bulb and put it in front of a mirror, we would be taking the light radiation that would be heading in the direction of the mirror and reflecting it back in the same direction of the light not directed towards the mirror. Hence you would have twice the amount of light going in the direction of the refelction. As we are doubling the amount of light, we have a "gain" of 3dB or 3dBi.

For instance, here's a list of intentionally open wireless access points around SF

--Pat / zippy@cs.brandeis.edu

Stephan

LANRoamer is a GPL'ed system that has been doing this for a while. We gave presentations on it at Bay Area Wireless User Group and Sbay.org back in June, I believe, before even the NoCat project started.

If you're into "bazaar" style software development, one thing you should note is that LANRoamer does network booting and upgrade reboots. So, if you contribute a useful feature to LANRoamer, it can be widely deployed quickly (based on our stability labels and the stability level each gateway owner has selected). Also, in addition to free accounts and revenue sharing to our access point providers, we also offer free courtesy accounts for people who run open access points (not just during a free beta), partly in an effort to thank the developers and "evangelists", but also to get them involved.

Anyhow, here is the software, including the latest LANRoamer network boot floppy or CD-ROM.

The network boot floppy currently requires that the first ethernet card be compatible with 3COM 3c59x, 8139too, Ether Express Pro 100, NE2000 PCI cards, Via Rhine, Tulip cards and PC-Net PCMCIA ethernet (the 802.11 card or the ethernet connection to your access point can be just about any card that Linux supports). Unlike NoKat (the last time I checked), LANRoamer can work behind firewalls, including NAT routers, even ones that distribute IP addresses that LANRoamer would otherwise use. Once your gateway is up, client machines can obtain addresses from your wireless gateway by DHCP and are taken to an SSL-based login page when they try to go anywhere on the web until they log in.

What UWB technologies can offer is that they increase the number of users and amount of bandwidth that can operate in the same space without interfering with each other, and they also have sufficiently entertaining options for directional data and longer distances that it might be possible to build a meshed distribution network that's got enough horsepower to be self-sustaining without lots of wired access points. That not only makes it more viable for wireless users to access services on each others' machines, but also to get better economies of scale sharing upstream bandwidth - N users on a 45Mps T3 connection get much more effective capacity than N/28 users on a 1.544Mbps T1 connection, plus you save the costs of running lots of small connections to lots of individual cells (the access costs for a T3 are typically about 10 times the access costs for a T1, and you get 28 times the bandwidth, plus you also have more users who'll be sending data to each other instead of to the outside world.)

There are a bunch of other projects like this. Including my own Ashland's Wireless Internet Project (AWIP) http://awip.truffula.net

Also there's....
http://personaltelco.net
http://seattlewireless.net
http://bawug.org
http://free2air.org
http://consume.net

a lot of these have been mentioned on slashdot before....

They're cool though :) (hence why i started another one...)

It always makes good media to (re)post about broken wireless networks that could be accessed from anywhere. Lots of dead tree magazines are writing about this.

Who says he is not detecting freely accesable networks that are made to be public. /. reported about this part my times before.

While the improvement in throughput is excellent, it comes at a cost of range. The 5.4GHz spectrum does not carry as far as the 2.4GHz band, used in 802.11b. This difference will be felt the most in long-range applications, whether it be a directional long-shot or the more omni-directional community wireless networks such as BAWUG or Houston-Wireless.

--
The Sphere Guerilla Net
Space City, TX

I would also ask folks to check out the Bay Area Wireless Users Group (http://www.bawug.org) mailing list archives for help as many folks on that list are doing long distnce 802.11 paths there and I am sure many of these guys will help you out.

Tim Pozar

This just appeared on the BAWUG list, with some info on Canadian regulations for the 2.4GHz band.

Here are some URLs you might find interesting: HPWREN (featured here recently) have a 45mb backbone using western multiplex tsunami kit, and 802.11b access points. They use solar power and batteries to power some backbone nodes.

Some other people using mostly 802.11b kit who will have some information you can use: BAWUG PersonalTelco.net NoCat.net Freenetworks.org

Using 802.11b or similar tech, you should expect each wireless hop to add about 5ms of latency, maybe a little more depending on distance. You can quite easily build a repeater by connecting two bridges together by a X-over cable. You could probably do this with Linksys WAP11 or similar, but over this type of distance you will find it much easier to use something like the high-spec version of Cisco Aironet 350 bridges (the 100mW versions will push the signal a lot further - 25 miles with 24dBi antennas - you can use Cisco's own, alternatives include Superpass (based in Waterloo), HyperLinkTech and others.

Aironet bridges let you set the distance of the link which modifies timing parameters (a slight problem with standard 802.11b over long distances), and their security is better than WEP.

There's plenty of homebrew opportunities for antennas and other related kit, although I guess they're probably of more use to people who don't have a budget to play with (: There's a collection of links on this page with a particular focus on homebrew kit.

try checking out this article linked to from bawug. I do this at home already (FreeBSD, Lucent Orinoco Silver card.

Several people on the Bay Area Wireless User Group mailing list have pointed out a large amount of factual errors in this article.
Such things as that the pringles cans are ANTENNAS not REPEATERS and that you can not get ANY wireless fully 802.11b access points for under about 160$ new (even on ebay).

For some more on this check out the mailinglist archive at
http://lists.bawug.org/pipermail/wireless/2001-A ug ust/thread.html under the subjects "Did you know you were a parasitic grid?","Infoworld writer responds
" and "Unprofessional conduct on the part of Ephraim Schwartz". Definately shows how little this writer actually knows...

Several people on the Bay Area Wireless User Group mailing list have pointed out a large amount of factual errors in this article.
Such things as that the pringles cans are ANTENNAS not REPEATERS and that you can not get ANY wireless fully 802.11b access points for under about 160$ new (even on ebay).

For some more on this check out the mailinglist archive at
http://lists.bawug.org/pipermail/wireless/2001-A ug ust/thread.html under the subjects "Did you know you were a parasitic grid?","Infoworld writer responds
" and "Unprofessional conduct on the part of Ephraim Schwartz". Definately shows how little this writer actually knows...

802.11b freenets are great and I by all means encourage more people to open them up and run them (I have a little one running), but they are hardly a realistic threat to ISPs. The simple fact is that WiFi just doesn't have enough range and penetration to make significant coverage economically feasible ad-hoc. It takes a lot of placements to get decent coverage, particularly when leaves, many walls, and most other obstructions attenuate the signal a great deal. Hell, look at all the money Metricom had to pump into getting decent coverage (different tech, but similar range issues).

If you look at the major freenet networks (such as SFLan and BAWUG here in San Francisco or others), their actual coverage is really quite tiny. Sure, you can find a good number more by war driving around the city, but that hardly gets to the point that were making a dent in the ISP revenue stream. While I'm optimistic on their expanding and the radios improving, what percentage of SF residents realistically would have usuable signal strength in their homes in 1, 2, even 3 years out?

If you do decide to run a freenet, get an external antenna with some decent gain, though WAP antenna connectors have to be proprietary, most are just reversed DNC or the like. You get a pretty shocking increase in range and penetration even with a 3db omni and a lot less sensitivity to the wireless card's orientation (which is all to often flat and sub-optimal for pickup). A lot of the freenet spec out relatively expensive hardware (< $1K for SFLan), but a little antenna hacking can get most any WAP to reach out for semi-decent range.

Regards, RJS

Agreed. In support of this, we provide a free courtesy LANRoamer account to anyone who runs an open access point that meets the other LANRoamer criteria (up most of the time, in our coverage maps, technical contact info provided, etc.).

I don't think this policy is on our web page yet, but it will be soon and we publicly stated it in our presentation at the last sbay.org meeting, and possibly in our presentation at the last Bay Area Wireless User Group meeting.

Shamelessly lifted from BAWUG 's links page, where there is lots of information about wireless hardware and software:

• Greater San Francisco Bay Area
  • BAWUG (Bay Area Wireless User Group)
  • SFLan (S.F. Presidio)
  • SBay.ORG (South Bay Wireless)
  • Mycal.NET (Petaluma)
• Burning Man (Black Rock City, NV)
  • PlayaNET
  • Internet BM
• United States
  • Colorado Wireless Exchange Cooperative
  • Xlan.ORG
• Outside the U.S.
  • Canberra Wireless Network (Australia)
  • Elektrosmog (Sweden)

Shamelessly lifted from BAWUG 's links page, where there is lots of information about wireless hardware and software:

• Greater San Francisco Bay Area
  • BAWUG (Bay Area Wireless User Group)
  • SFLan (S.F. Presidio)
  • SBay.ORG (South Bay Wireless)
  • Mycal.NET (Petaluma)
• Burning Man (Black Rock City, NV)
  • PlayaNET
  • Internet BM
• United States
  • Colorado Wireless Exchange Cooperative
  • Xlan.ORG
• Outside the U.S.
  • Canberra Wireless Network (Australia)
  • Elektrosmog (Sweden)