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Cringely's Bank Shot
Michael A. Lowry writes: "You may remember how Robert Cringely used a couple of directional antennas to get an 802.11b link up across a 10.5 km wide valley. The original Slashdot discussion is here. Well Cringely has done it again. This time, he has set up a passive repeater in an oak tree on a nearby mountaintop to bounce a 2 Mb/s signal around a hill that lies between his house and the acces point in Santa Rosa. Read about it here. Details about the homemade hardware he used can be found here. There's going to be a lot more of this in the near future."
I know this isn't the same, but where I live there is a company getting wireless broadband to rural towns by putting atennas and transmitters on the top of grain elevators. This works out pretty good since the terrane is flat and you can see another elevator from the top of your current one. I don't know how much area they cover, but it seems to be an interesting solution.
Because Cringely doesn't have DSL service. He's piggybacking on someone else's service. So there's no traceability to Cringely unless his middleman says something.
http://pythonisito.blogspot.com/
For example, with FRS radios it is specifically forbidden to replace the supplied antenna at all, and the supplied antenna cannot be of a gain type. I'm pretty sure that there are similar restrictions on cordless phone antennas.
Has Cringely read this article which basically says the hack he's using to increase his Linksys WAP11 power output DOES NOT WORK?
It's passive. No power needed. Basically, a wave received from one antenna will travel down a transmission line to an antenna connected at the other end and radiate out (and vice versa) with very little loss.
For the unliscensed use of the ISM band at 2.4Ghz you are not allowed to exceed 1W radiated power. This means that a 100mW radio connected directly to a 24Dbi dish antenna is actually too powerfull. This is ok because most people who use a dish with that kind of gain put it up on a pole. Using even really freaking expensive cable you lose a couple Dbi per meter of cabling.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Have you ever seen BreezeCom (now alvarion) radios? They are built like a tank. I dropped one off a tower once (~20ft) onto concrete and it was fine.
The other solution is just to put all your stuff inside an enclosure with whatever NEMA rating your environment requires. Add a heat exchanger and UPS in there and you have a nice sealed up shielded box that's good to contain about any piece of computing equipment you want.
If you are thinking of experimenting with your wireless equipment be aware of the FCC regulations
That's what 2.4Ghz is for - keep it under 250mw and you're fine.
Reboot macht Frei.
That doesn't necessarily make it legal, though - take a look at some of the recent action by the FCC against people and organizations violating the Communications Act of 1934/1996. The interesting thing is that against individuals, a good deal of the action seemed to focus on pirate radio.
I found this stuff from the FCC interesting, too:
Of course, if you have a lot of free time to kill, you can read the whole Communications Act of 1934, but I don't think there's going to be much on wireless networking in there. I think for now, since Cringely is already a subscriber to the ISP that he's banking off of, he should be fine, especially since the FCC is allowing people to set up Low Power FM stations in their homes. There doesn't really seem to be any precedence to this from the FCC's point of view.First they ignore you, then they laugh at you, then they fight you, then you win. --Ghandi
First they ignore you, then they laugh at you, then they fight you, then you win. -- Gandhi
So, having proved the concept, I am going to go back to my slightly less offensive bootleg DSL connection until I can find out who owns that oak tree and make my new installation legit.
I was going to suggest getting a plat book from the Sonoma county extension office. But I called them, and they don't do plat books... (Maybe plat books are just a midwestern thing. I'm used to most every farmer having a plat book that shows who owns which acreage.)
So it looks like for Cringely to find out who owns that part of Bennett Mountain he's going to have to go to the Recorder or Assessor's office and find it on a map there.
I thought that even his boosted signal was low enough to be considered unregulated. At that point, there is no FCC guidelines concerning interference. Were he using a 10 watt transmitter, he WOULD be regulated because he might interfere.
The danger of using anything in the unregulated area is that you might get hosed by other unregulated users. If you need the reliability/durability/security, you have to pay for it.
Jesus was all right but his disciples were thick and ordinary. -John Lennon
For those moderators not paying attention, the parent post is an obvious troll.
This is precisely why we need the FCC to regulate people's use of this equipment.
Cringely's setup is regulated by the FCC and is within FCC specifications. There is nothing illegal (as far as the FCC is concerned) here.
Did Bob Cringely ask a single person living in downtown what they thought of his terrific internet access plan?
Why would he? Does the neighborhood get a vote every time someone turns on a cell phone? What about when a ham radio operator fires up his 1,500 watt amp? What about when someone turns on a microwave oven?
What about the those people who use approved wireless equipment (phones, wireless networking) and now have to deal with the background noise
Cringely was using an FCC type-accepted device well within its specifications. Did you miss that part of his article?
coming from his souped up repeater?
His 'souped up repeater', as you call it, is a couple of antennas back to back. It's passive. His antennas don't put out power, they just focus the energy. With 18db of gain, his 100mw signal is still under five effective watts.
Wait, I'm sure he did a thorough study of his setup to make sure that it didn't interfere with transmissions by public safety agencies, right?
Dude, take a basic radio class. He isn't changing the operational frequency. He isn't using an illegal amp that might cause out of band splatter. His third order distortion won't be affected by a passive antenna. There is harmless.
What stopped him from using a 10 watt transmitter, so that the connection would be even faster?
If he had a ham radio license, he could legally run up to 1,500 watts of power, operate an active repeater and use whatever antenna array he wanted all in the same frequency range he is using now. As an added bonus, he still wouldn't have to fill out any paperwork, get any government approval or take a poll of his neighbors.
Follow the rules and don't subject other people to your homebrewed technology.
Once again, other than unlawful use of a tree for the purposes of geekness, I he hasn't broken any rules.
If you want to learn something about radio (and, trust me, you're really ignorant now), why not surf on over to the American Radio Relay League. They represent hams across the world. They have some very good teaching materials. If you study hard, maybe you can even get a ham license. It really is pretty nifty.
InitZero
I've done some work myself on making a passive repeater for other purposes. I've found that even duct-taping a copper circle of one wave length onto my usb wireless adapter for my laptop will improve link quality more than 10% when you go through a few obstacles. I've been lazy, but if you want to do something pretty cool build a directional antenna (any with good gain) and run the cable to a copper circle of length 11.168cm(Ch 6) (don't connect the ends to each other, just to the coaxial cable). This should give you much better gain and distance on your laptop :) you could build the double quad antenna (double the wave length in length, looks like and you connect the coax to the center such that it ends up being two stacked quads), and it would give you at least 3db gain more than a single quad and be omnidirectional so you can move your laptop around :) There are lots of documentation on how to build these antenna's. Build a couple and connect them to each other and viola, you've got a passive repeater.
Karma Clown
http://www.freenetworks.org/
Deleted
FCC Rules part 15.247 is the reference here. The reason we use DSSS encoding is that FHSS is limited to 0.125 watts in the 2.4 ghz band. 15.246(b)(2). The 5.725 ghz band allows 1 watt in most spread spectrum modes (802.11a/g?)
15.247 (b)(3)(i) allows high-gain directional point-point links. For every 3 db above 6 db gain, you have to reduce your peak output power by 1 db.
Of course, if you get a basic ham license, you can increase this quite a bit. However, you then cannot encrypt your traffic, IIRC.
"'Tis great confidence in a friend to tell him your faults, greater to tell him his." --Poor Richard's Almanac
"a couble Dbi per meter" ??? mabye if you use RG-174
Normal LMR-400 only loses 6.6 dB/100'
2 inch heliax (around $1/ft) would lose less then 1.5dB/100'
Please do some research before posting!
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Actually when using a directional antenna, the FCC says you can go over 1 watt EIRP. If the antenna is over 6dBi you have to lower the "maximum peak output power of the intentional radiator" by 1dB for every dB your antenna is over 6dBi. Further, for a fixed point to point link, this is reduced to 1dB for every 3dB your antenna is over 6dBi.
You do need to know the cable loss between your radio and your antenna. With your 24 dBi example and 2dB of loss through the cable, and 1 watt EIRP == 30 dBm:
directional antenna over 6dBi (have to reduce output power by (24-6) or 18 dB):
30dBm + 24dBi - 2dB - (24dBi - 6dBi) = 34dBm (== 2.5W EIRP)
same scenario for a fixed point-to-point link (have to reduce power by (24-6)/3 or 6 dBm):
30dBm + 24dBi - 2dB - (24dBi - 6dBi)/3 = 46dBm ( == 40W EIRP!)
A good summary of this info is found here:
The FCC's Part15 Rules and Regulation and 802.11b emissions in the ISM 2.4GHz Band
check it out and double check my math!
I myself live in a bandwidth black hole which I just happen to be in the center of. So, I actually started researching and buying gear to hook into work's T1, which is about 4.8 miles away. The gear I decided on was two Orinoco (or WaveLAN as they used to be called) cards with Linux boxes to match to keep costs down (besides, Linux makes for a great wireless router). My antennas are 24dBi gain Hyperlink parabolic grid antennas. I already have the cards working in my Linux installations and am ready to hook up the antennas soon. The only tricky part is that my path to work is slightly obscured so I'm hoping I have enough power and gain to be able to punch though. Hopefully the bandwidth gods will look favorably upon me. I've never had a high speed connect at home (and probably never will if this doesn't work :/)
:)) I also asked how he got around mountains and such.
One of the coolest projects I found while researching this was the HPWREN project at UCSD. Check out their pictures, it's hella cool. In a nutshell they are running a 45Mbps (802.11a) wireless backbone across the Santa Margarita Ecological Reserve using mostly off-the-shelf equipment, for the purpose of hooking together the facilities strewn across it. They even have remote cameras hooked in that can be remotely controlled through the network, and other testing stations that send data back to them in realtime.
I dropped an email to the project lead and I asked him what kind of gear they used. He said they used a Western Multiplex Tsunami for their backend, Hyperlink for their antennas and WaveLAN and Cisco Aironet for their PCMCIA cards (you can now see how I constructed my parts list
Well, in certain places they have powered relay stations. Naturally I wondered how they were powered, and he said some of them they could get electricity to, but others they actually have solar panels powering the relays. Damn. For you real hackers he mentioned there was a parts list for the solar power array somewhere on the website, but I never bothered to try and find it.
I've noticed some arguments regarding amplifying 802.11, and thought I'd help clear it up. FCC Part 15.247 governs the unlicensed ISM (Industrial, Scientific, Medical) band, and dictates that you can amplify the signal up to 1 watt (1000mw) This gets tricky when you start using directional antennas >6dBi gain though. You may find more detailed info here..
-R
Bullshit.
/ bo s/bos_s.pdf
There's an incredible amount of dark fiber strung all across the USA. (No idea of elsewhere, but Europe seems to be well wired.) Sunk cost. A glut.
(See: Qwest, Global Crossing, Level 3, PSINet, AT&T, Sprint, Verizon, SBC, Bell South, Williams, Teleglobe and Cable & Wireless)
That said, there are a huge number of people wired to the internet right now via SOME method. There are quite a few hooked up via some broadband method. There's very obviously a huge potential consumer market here for broadband. If those owners of dark fiber ever want to recoup said costs they have got to figure out a way to GET US TO USE IT.
See:
www.cwt.vt.edu
www.its.bldrdoc.gov/meetings/art/art00/slides00
www.business2.com/webguide/0,1660,65069,FF.html
So why isn't this happening with today's existing infrastructure?
See: lame duck ILEC's and greedy-fucker media conglomerates.
Infoworld's "I Cringely" column has been written by different people under that pseudonym. Do we know who is actually doing this?
m l
One of the previous columnists - Mark Stephens - has been using the names for books (Accidental Empires) and tv (Nerds series). There have been at least two more Bob Cringely's since him in Infoworld.
More info at: http://www.xent.com/FoRK-archive/summer96/0088.ht
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