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Build Your Own 10Mbps Microwave Data Link
Rob writes: "I found this site called The Microwave Data Link Project where a guy is attempting to link 2 LANs (2 miles apart) by a 10Mbps Microwave Data Link. I've seen the plans for these links, but never wanted to learn all that amateur radio stuff, but this guy is going to lead people step by step how to build it, including how to get your FCC License, and more. Should be interesting to follow the progress!"
The FCC has limited amateur data rates to 56k on frequencies above 420Mhz....
-Craig
KC5UMA
We're here to give you an OS, not a religion.
10Mbps wireless ethernet you can build:
http://www.technocrat.net/937014982/index_html
--Kevin
=-=-=
more power. Remember, if you have your ham license, you can run up to 1500 watts.
Of course, you have the commercial and no-encryption rules to contend with as well.
I was thinking of that too, but I was just going to stick the RJ-45 on the back bumper. Little flip-open connector covers specifically designed for vehicle use are readily available for hiding trailer harness wires.
OTOH, your later reply about driving in and having the car pop up onto the home LAN is really cool.
But what about issues of powering it? You're not going to want to leave the computer on all the time because your car battery won't live long (days, probably, and car batteries aren't meant for deep discharge cycles); wake-on-LAN features might work. But, at least if it's wired, you can make your own little custom plug including network connection and a separate power circuit to run the computer.
Fire and Meat. Yummy.
How is this offtopic? Suppose I as a Canadian wanted to make one of these legally.
Some moderators are power freaks.
`k
i have misplaced my signature.
A hypocrat would therefore be a person in a position of power in a hypocritial organization. Like a high-level Microsoft manager.
No, Thursday's out. How about never - is never good for you?
I use them to surf on my laptop while downstairs and away from my DSL connected upstairs bedroom computer. They still worked when I took my laptop out to my car (about 150') to test range (and to start planning to do pretty much what you have in mind, a car mp3 player with connectivity so I don't have to remove the laptop to refresh the music).
They even came with a 2 user licence for wingate, which my be helpfull if your linux box (like mine) doesn't have any free isa slots but your winblows gamer box does.
Email me if you need more info.
--
Does narcissism count as a hobby? --Shawn Latimer
Not over ham radio...
You are NOT allowed to encrypt any of your data, unless you are controlling a space based transmitter (that is, a satellite).
If you are needing to encrypt, try something like the Apple Airport thingy.
I looked into setting up some WAN links such as this with commercial equipment a couple of years ago. I think California Microwave and TRW were a couple of companies that make LOS (line of sight) microwave equipment designed exactly (or close enough) for this purpose.
At the time, the equipment was expensive, but still financially viable over a year or two compared to dedicated T1 lines. I believe in 1997 I was getting quotes of around $10,000 for a single 2 mbps link (anyone, which is it, Mbps or mbps?). The price of the link did not increase significantly as the speed went up. For instance, I belive it was only a couple of grand more for the 10 mbps link. The large initial cost was for the antenna systems and the radios. For instance, 10 mbps data and 2 mbps data traveled over the same frequency, but the 10 mbps equipment had tighter tolerences and was slightly more expensive.
Anyhow, the biggest problem with a system like this is security. To really secure a link like this, one will need a spread spectrum modem. Those aren't cheap. Spread spectrum "spreads" a data signal out over a wide band of frequency. If done correctly, the signal is difficult to detect apart from normal background noise. Also, to eavesdrop on the signal, one would need the right codes that the modem uses to spread the signal out and then put it back together.
For instance, with spread spectrum, one could transmit two different signals on (nearly) the same frequency, but because 2 different codes are used to split up the signals, they could be decoded at the distant end without interfering with each other.
Other advantages to spread spectrum include resistance to jamming and low succeptibility to background noise. One would be less likely to lose a signal due to rain or snow or some jerk with a 300 watt CB radio in his car.
I believe this microwave project will meet with success, but it won't be anywhere near what I would call reliable enough to use in a business environment.
I am running a three mile 11mbit link via two Wavelan cards. It was much easier and cheaper than this setup.
The cost of me doing it is quite a bit more than his project since I have to relay to get around trees. Microwave has to be line of sight. However if I had line of sight between 2 networks up to 30 miles away I could use:
2 lucent wavelan cards: $150 ea
2 24db grid dish antennas: $150ea
2 40' cables $50ea.
Total $700
I could save money here on the antenna's, get a couple 10dbi antenna's for $70ea, and still get 10 miles.
Figure the time going into making the stuff, and licensing (this is unlicensed stuff I use), the excellent software, stability, etc, not to mention the range and that $200 difference goes away really fast. Not to mention we'll have to see if he make it at $500.
Before everyone gets excited about doing this project, please take the time to understand that Amateur Radio is specifically prohibited from being used to carry commercial communications. Be mindful that what constitutes "commercial" communications is subject to interpretation. Note also, that encryption *may* be prohibited under this regulation (No SSL for you!)
Here's an excerpt of the relevant federal regulation:
(a) No amateur station shall transmit:
(1) Communications specifically prohibited elsewhere in this Part;
(2) Communications for hire or for material compensation, direct or indirect, paid or promised, except as otherwise provided in these rules;
(3) Communications in which the station licensee or control operator has a pecuniary interest, including communications on behalf of an employer. Amateur operators may, however, notify other amateur operators of the availability for sale or trade of apparatus normally used in an amateur station, provided that such activity is not conducted on a regular basis;
(4) Music using a phone emission except as specifically provided elsewhere in this Section; communications intended to facilitate a criminal act; messages in codes or ciphers intended to obscure the meaning thereof, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification;
(5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services.
The full regulation can be found here.
Chuck Milam, KF9FR
Just use standard wavelan stuff. Get some PCMCIA cards and antennas, point them together....... No licensing required.
I was working for a school district in northern Canada and we got three towns connected via 10MBit wireless. The towns are 60km apart. We have one central mountain station to actually interconnect them. In a place where where you _can't_ get DSL, Cable, T1, etc., it works pretty damn good.
Two I am familiar with are Breezecom and Aironet , just bought by Cisco. If you poke around, you'll find many of these products have Linux drivers .
"one treats others with courtesy not because they are gentlemen or gentlewomen, but because you are" --G. Henrichs
Yes, exactly. The low-cost Gunn-diode units being used couldn't be modulated much faster than about 2 Mbps.
Second, the statement about "not much operating at 2Mbps" as a reason for trying for 10Mbps makes it sound like he really doesn't understand the way asynchronous networks function. At least with tcp...
It has nothing to do with protocols. The problem is finding something that pumps data in a useful manner at 2 Mbps. A 10-Mbps Ethernet card can be had for next to nothing. But what card do you use if you need to slow down to 2 Mbps? Thus the desire to increase the project's speed to 10 Mbps.
Of course, as other people have pointed out, the legality of a 2Mbps HAM link, let alone 10Mbps, is quite suspect. Someone with access to recent FCC rulings should comment on it. A licensed amateur may design and build their own device to transmit legally in the HAM bands, and it seems from the rules most people know about that the 10ghz HAM band is limited to 56kbps.
Not so. On any frequency above 450 MHz, US hams can use any digital bandwidth that will fit inside the band. See the FCC Rules at 97.305(c) (and 97.307(f)).
Yes, these regulations are true for voice transmissions. However, since the signal is digital, music/data/anything else CAN be transmitted over the air digitally as long as it is not commercial data. As far as the rules say, it's ones and zeros over the radio in a publicly documented format (AX.25 in this case).
Tristan
Call sign: KF6MUY
what about cabs? Don't they use those radios all the time?
--
--
Stay tuned for some shock and awe coming right up after this messages!
I love projects like this. This would have been great last spring when my best friend and I lived a couple of miles apart. Maybe I can steal internet from the dorms like this ;-) This reminds me of one of my favorite books The Robot Builder's Bonanza. I think that I'll pick up some parts tonight after work.
Eh...
Of course, that could be because all the AP's are too busy with first posts to bother reading.
Could this be used to communicate with a boat cruising around a lake with the base from home? A two mile radius isn't the world, but it would be fine for an afternoon cruise.
I'm sure there are lots of other applications around for connecting houses, stuff like that too.
Of course I use Microsoft. Setting up a stable unix network is no challenge
Spending the time to get a ham radio license has been very rewarding for me, especially HF contesting, which uses 2.4 KHz of bandwidth!
p.s. If I want encryption, I'll use my ISP which I pay for.
Amazing magic tricks
Am running off an 11mbps link to work 4 miles away and thru a relay right now with lucent/orinoco wavelan hardware and outdoor routers.
Not much to learn, just a lot of climbing 200' towers.
You are in need of serious help if need net access for an afternoon of boating. Whats the point of going on a boat if you are sitting at the computer? Forget about the net for a few hours, its healthy.
Only the State obtains its revenue by coercion. - Murray Rothbard
First they put internet connections in microwaves, then vice versa. It's always the same.
--
Wanna hook MAPI clients to your Tru64/AIX/Linux server?
Linux MAPI Server!
http://www.openone.com/software/MailOne/
(Exchange Migration HOWTO coming soon)
I hate how they meter bandwidth like electricity, whats the phone company pay for its upkeep? Nothing except for their electric bill :) Anyhow around here you can get DSL thats 7.1 meg down/ 1.5 meg up for less than $200 a month. Tell the phone company to stick it.
Only the State obtains its revenue by coercion. - Murray Rothbard
Does anyone know what the equivalent license in Canada would be?
BlackNova Traders
What kind of relay? I've got six miles through a hill.
73
KK5WA
sine puella vita suget
I don't know about microwave, but RF is capable of going 3.5 miles at 11Mbps (in the 2.4GHz range). See here
This is supposed to be great art. So why does it look like a bunch of decapitated naked people? -- Calvin
For all you "Remember the HAM rules" guys, keep in mind that it won't be particularly difficult to adapt this to other wireless technologies and such. CB would be just downright rude, but there's always other frequencies.
"I'm not even supposed to BE here today!"
I think your T1 estimate's a little off, last I checked a (cheap) full T1 was going for ~$1000/month, perhaps slightly less. That's a whole fuckofalotta bandwidth 'though, 1.544 Mbits. A T1 actually consists of 24 channels each capable of 64Kbits.
:)
T3's are (contrary to apparently popular belief) not 3 T1s, but actually 28 T1s, or 672 channels each running at 64Kbits. They are correspondingly a buttload more money. I can't find a price quoted *anywhere*, it appears to be one of those "call us" things
alt3r3go
badges? we don't need no steenking badges!
Which brings up another issue -- what the hell is the point? Since the purpose is to connect two LANs, imagine you accidently fire up SSH to log into a machine on the other LAN. Three key strokes and you're a criminal. Or if you're sharing an internet connection your browser can (and probably will) get redirected to an SSL site. The idea is cool, but in the long run you're probably better off using equipment that isn't licensed under the amateur radio rules.
I don't know how correct your information is there. Just about all microwave transmission takes place in the Ghz range. Satellite uplink/downlink are frequently in the 8 - 25 Ghz range and line of site microwave is only slightly less.
Shorter wavelengths are better than longer for travelling through objects and over long distances (line of sight). Remember your 900Mhz cordless phone, now pushing up to the 2.4 Ghz range? The reason behind that is farther transmission with less interference.
As to the ISP you mentioned, did they use directional (parabolic) antennas? All microwave transmission is line of sight. You need really low frequencys, like AM to be able to go over the horizon. Unless of course, you've got a couple of thousand watts of transmitting power, and then you can do something called troposcatter. Ranges of over 100 miles are available in that situation.
Without anything blocking your view, you can easily get 30 miles by line of sight. Also consider all of the microwave links you will see the phone companies have connecting small villages and cities out in the boonies. They are much cheaper than stringing enough copper that far.
If you live in a downtown area, if you look to the tops of buildings, you'll see many antenna horns and dishes (look like dinner plates almost) littering the top of the skyline. All of those are high freq microwave links.
Oh yep, it is hip for the guy to put a LAN and a LAN in one WAN, but I am a bit sad to see no one cry for the dog or cat or pig who die. I bet he did not try to see if it may get hot on the way. Too bad for the old man who is on the top of his hut and may get a bit too tan.
[If you can not say it in 1 or 2 or 3, why say it at all?]
-----
"Patience is a virtue, afforded those with nothing better to do." - I don't remember
1. You have to identify the stations at both ends of the link every 10 minutes, and at the end of the transmission (when you go off the air).
2. No profanity or other "obscene" things can go over the air. Since those "obscene" things would be encapsulated within TCP/IP, I'm not sure if this applies, but it may.
3. The operator of the link cannot profit financially from the operation of the link. In other words, it could be done for fun or to contact friends, (QUAKE DEATHMATCH!) but it could not be used to connect two offices of a business that employs the operator. FCC regulations are pretty hard and fast about this. It used to be that you could not do any business transactions on the radio, but this was recently amended to simply disallow profitmaking.
Rather than use amateur radio, I'd try the unlicensed 802.11B radio gear. I've successfully hooked up two offices with WaveLAN equipment for around $800, over a 2 mile path.
... referenced in the article, at http://www.qsl.net/ke5fx.
/.-worthy. The response came back in about 5 minutes:
:-)
:-)
Amusingly, I submitted the project page to Slashdot myself about a year ago, when I first got the link working. When the submission was rejected, I wrote to one of the well-known admins at Slashdot asking what I needed to do to make it
I just didn't think it was interesting enough.
Sorry.
--
| (admin name omitted) | Just want to be misunderstood,
| (admin name omitted) | I wanna be feared in my neighborhood.
| http://slashdot.org/ | Just want to be a moody man,
| codejockey*gangstero | say things that nobody can understand.
| flove*lovemachine*wr | --Pete Townshend, Misunderstood
Dejected, I was forced to admit that my news-for-nerds quotient just couldn't compete with the guy who built a PC case out of Zebrano wood, or whatever the story-of-the-day was at the time. Consequently, Rob gets major props from me for doing a better job writing up the submission than I did.
Now for the bad news: out of many thousands of hits my site's received over the past year, only one guy, an EE professor at a local university, has successfully duplicated my efforts. In my mind, that somewhat validates the unnamed Slashdot admin's decision not to publicize the project in the first place. People, this is not a project for beginners or casual electronics buffs! In the year since I finished the project, a couple of excellent alternative solutions for RF data links that make good use of off-the-shelf hardware and homemade antennas have come to light. For instance, there's a good page on the topic of modifying Proxim Symphony cards for long-range service at Low-Cost Wireless Network How-To. I would have to say that this is a better approach for 99% of the people who have looked at my microwave link page and thought about building it. Heck, in retrospect this is what I should have done, instead of putting in all that engineering time on a 100%-custom solution.
My own 10-megabit link has been running great since last June with only a couple of hours' downtime for maintenance and tweaks, and it's easily the most 'educational' project I've ever tackled. But I think it's important to temper peoples' expectations. If you are an experienced electronics hacker with access to a very well-equipped RF test bench or a university EE lab, and you just want to spend a lot of time and money building something something cool, then I highly recommend my microwave link project. If not, do yourself a BIG favor and check out the various wireless-Ethernet card tweaks that have been springing up on the Web.
-- John Miles, KE5FX
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
Cabs do not use HAM (Amateur) radios. They use radios and frequencies specifically leased and licensed to them by the FCC for this commercial purpose. Amateur radio is totally different.
... referenced in the article, at http://www.qsl.net/ke5fx. I'm going to be sort of redundant here, and repost this message as a reply to the "first post", just to make sure all interested parties see it. I got to work late today, so my initial reply is lost somewhere in the noise at the bottom of the article. :-) Sorry for the duplicate post -- if someone can down-moderate the copy at the bottom I'd appreciate it.
/.-worthy. The response came back in about 5 minutes:
:-)
:-)
Amusingly, I submitted the project page to Slashdot myself about a year ago, when I first got the link working. When the submission was rejected, I wrote to one of the well-known admins at Slashdot asking what I needed to do to make it
I just didn't think it was interesting enough.
Sorry.
--
| (admin name omitted) | Just want to be misunderstood,
| (admin name omitted) | I wanna be feared in my neighborhood.
| http://slashdot.org/ | Just want to be a moody man,
| codejockey*gangstero | say things that nobody can understand.
| flove*lovemachine*wr | --Pete Townshend, Misunderstood
Dejected, I was forced to admit that my news-for-nerds quotient just couldn't compete with the guy who built a PC case out of Zebrano wood, or whatever the story-of-the-day was at the time. Consequently, Rob gets major props from me for doing a better job writing up the submission than I did.
Now for the bad news: out of many thousands of hits my site's received over the past year, only one guy, an EE professor at a local university, has successfully duplicated my efforts. In my mind, that somewhat validates the unnamed Slashdot admin's decision not to publicize the project in the first place. People, this is not a project for beginners or casual electronics buffs! In the year since I finished the project, a couple of excellent alternative solutions for RF data links that make good use of off-the-shelf hardware and homemade antennas have come to light. For instance, there's a good page on the topic of modifying Proxim Symphony cards for long-range service at Low-Cost Wireless Network How-To. I would have to say that this is a better approach for 99% of the people who have looked at my microwave link page and thought about building it. Heck, in retrospect this is what I should have done, instead of putting in all that engineering time on a 100%-custom solution.
My own 10-megabit link has been running great since last June with only a couple of hours' downtime for maintenance and tweaks, and it's easily the most 'educational' project I've ever tackled. But I think it's important to temper peoples' expectations. If you are an experienced electronics hacker with access to a very well-equipped RF test bench or a university EE lab, and you just want to spend a lot of time and money building something something cool, then I highly recommend my microwave link project. If not, do yourself a BIG favor and check out the various wireless-Ethernet card tweaks that have been springing up on the Web.
-- John Miles, KE5FX
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
The FCC's commercial-purpose rules for the Amateur service have been significantly relaxed over the past few years. You wouldn't want to use a ham-radio link like this to run a commercial ISP, but using it to order stuff online is fine. It's no different than using a repeater's telephone-link capability to order a pizza, for instance.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
...a project such as this can be conducted entirely under the auspices of Part 15, which is subject to none of the restrictions you cite.
Also, commercial usage rules have been substantially relaxed lately. You should not try to sell ISP services over a link like this. OTOH, using it to order stuff over the 'net is fine.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
"Well, good luck finding a judge that doesn't run a bestiality site."
All that link shows is that they went to my page and hit 'Save' (and without asking my permission to mirror it first, making it tough for me to update their copy with corrections, grrr.)
If the L0pht guys have actually built one of these puppies I'd love to hear from them -- AFAIK there has been only one successful duplication of my results so far.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
3154
"It's tough to be bilingual when you get hit in the head."
T3's fall in to that 'if you have to ask, you can't afford it' category... thus, no prices...
"It's tough to be bilingual when you get hit in the head."
A T3 is $45,000 a month.
No comment at this time
Why would you want to use a regulated communications medium which makes it impossible to do anything useful without paying a fortune when you can use a laser?
Ahh this reminds me of the days when a group of us try to steal ethernet connection from the only dorm on campus that had ethernet. (Go hokies!) He had nad a nice little wireless transceiver unit, but we just going 100 feet had caused us to have roughly 40% errors in the test packets that were sent... and the speed wasn't consistant... would be nifty if this guy can do it :)
Apparently the technology has advanced since I last saw it :)
At the conference I was at, they were pushing Microwave for ~2Mbps at up to 5 or 6 miles when direct line of sight was available, and some kind of infrared for when direct line of sight wasn't (i.e. the infrared transmitters could go through buildings).
Shorter wavelengths are better than longer for travelling through objects and over long distances (line of sight). Remember your 900Mhz cordless phone, now pushing up to the 2.4 Ghz range? The reason behind that is farther transmission with less interference.
Perhaps my understanding of this whole concept is fundamentally flawed? High frequency=short wavelength, I'm positive of that. Low frequency waves are more of the type to pierce solid objects, I ?think. Any input anyone?
As to the ISP you mentioned, did they use directional (parabolic) antennas?
They used directional (parabolic) antennas, and had direct line of sight, i.e. they didn't go over the horizon. One of the owners of the ISP was lucky enough to own some property on the right side of a large hill just on one side of the border, I believe we set the other dish up on the roof of the building a mile or two away.
alt3r3go
badges? we don't need no steenking badges!
L0pht Heavy Industries has been working on a 10Mogobip wireless network for two years now, they've gotten nodes in Boston, Derry New Hampshire, Cambridge Massachusetts, and Somerville Massachusetts.
Apparently, they have gone beyond simply using microwave, they are also using radio (which is a staple to the guerrilla.net system)...and the security breach he was worried about has been solved...by (1) an NSA approved encryption system, and (2) (which hasn't been implemented) another encryption system "to keep the spooks out".
Ugh...this looks bad, pardon my poor grammar, as I've not completely woken up. For more information, please click the link above.
0100100000100000011010010111000010000001100001001
try out the excellent kits from my suppliers in Melbourn: Talking Electronics.
I notice thay also have a site in USA
with details of electronics.
THESE PEOPLE ARE VERY GOOD AND VERY OPEN SOURCE
about their ideas: e.g. how to transmit 800metres in a built up area at 100Mhz with only a few milliwatts...!
The transmitters are designed for Audio
so we can use the Amateur radio linux drivers
with the transmitter plugged into the soundcard.
I have not done this yet.
Theoretically, we can boost the bandwidth to 1Mbs.(1% of the frequency).
!#
(Mainly for the benefit of others reading your comment.) The idea behind amateur radio is that it's a hobby, and meant for experimentation and for trying new things, learning, etc. It's not meant to do the job of something you can find commercially.
So generally speaking every signal you send over amateur frequencies must be things that a) you're perfectly comfortable sharing with the rest of the amateur radio community (thus the rest of the world); and b) aren't things that should probably be sent via some existing, equivalent (probably commercialized) route.
In this case, the guy's having fun trying to learn how microwave transmissions work, and what better way to learn how to do these things than to get an amateur license and actually build the darn thing? But the regulations say if he wants to use this link for anything but completely open, completely personal use, he needs to pursue a commercial license (or use a non-amateur product).
For this reason you will not find amateur digital links directly connected to the Internet for any Joe Schmoe to (perhaps inadvertantly) send anything violating FCC regulations over amateur radio frequencies. Things like porn, advertisements and commercial activities do not belong on amateur radio frequencies, and nowadays the web is full of it. In a way, this also hinders a lot of amateur radio digital activities, since we're effectively limited to e-mails and other communications between HAMs.
But this is just one area of digital amateur radio. We've got several satellites in orbit, some capable of doing digital work, and we have new cool things like APRS for instant world-wide messaging (even via satellite if you're in the boonies) and GPS positioning. You could build a home-made LoJack out of something like this.
Dave, WL7RO
That reminds me of an engineer at a Denver TV station. He said the engineers who ran the mobile trucks carried maps with the best path for selected areas. Many of them bounced signals off the skyscrapers downtown!
I always thought the microwave transmitters they use would make excelent data transmitters (at the time, VBI was the fastest game in town). You'd need a license, but I don't think they are very expensive.
"Well, good luck finding a judge that doesn't run a bestiality site."
... that the link on the posted site goes directly to my project text description. If you visited the KE5FX site before I updated it with a link back to my home page, you probably didn't see the schematics, waveforms, and photos associated with the project.
The correct link to the project site's front page is http://www.qsl.net/ke5fx. Sorry for any confusion.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
All microwave transmission bit error rates can be improved using standard diversity techniques. Time diversity, sending the same data twice. Accomplished through forward error correction and literally using two transmitters/ receiver pairs with lag placed on the second transmission. Space diversity, using two transmitter/receiver pairs separated laterally relative to the transmission path (a Flock of birds flies across one transmission path but does not affect the other) Frequency diversity, again two transmitters or a single frequency hopping transmitter (ala CDMA cell phones).
Using two transmitters does not mean having to use more frequencies. Using the same frequencies but changing the polarization of your antenna provides 83 dB of attenuation between transmission paths. Ideally you would use several of these diversity methods to give you the most paths possible. your modem also must be smart enough not only to handle multiple redundant paths it must also decide what the "best" data bit is if two bits in the same frame from different paths are interpreted differently by the receivers.
My eyes gloss over when hackers discuss the linux kernel in minutiae. I'm sure you are all there now.
If voting were effective, it would be illegal by now.
I am looking into the possibility of using such hardware to link to another residential location, only about 1/2 mile away, but neither location has a big tower to put an antenna on, and there are probably trees in the way.
As you clearly have some experience doing this, perhaps you could suggest a way to accomplish this? I'm sure others who have similar situations would also be interested in any information you can provide.
--
--
--
grep "xercist"
Those crazy guys down at the l0pht were doing this a number of years ago with their GNet project. It doesn't look very difficult to build, the main problem being "line of sight" or something /VERY/ close to it. Also doing anything more than a few miles (100miliwatts) can get expensive.
All you really need is good soddering skills and basic electronics knowledge (more than you need for your ham license)
Possibly the largest problem with this is the FCC's rules on "codes and cyphers" which strictly disallows using them in anyfassion exect to control remotecontroled hobby craft (yeah you should hear the rule on transmitting music if you thought that was silly). I don't know about you but setting this up would be oh so much more uber elite using IPSec on both ends.
as for EPA problems...microwave is directional and so long as there isn't anything in the way...I wouldn't suggest looking into while transmitting if you like seeing...
Getting the ham license is a joke, anyone who has any electronics knowledge and a handful of brain cells can pass it. I did mine in under a 3/2 mins (35 questions or so) and got one wrong.
but hey if anyone of you lives in Grand Rapid MI, letme know..I've been looking for someone to go in on a project like this but the only guy I know lives 7 miles away in a ditch (seriously)
-RijilV
For more info, try Cellular Phone Antennas and Human Health, a FAQ page by John E. Moulder, Prof of Radiation Oncology. He even has a section on the Israeli low-level RF health claims.
Dr. Moulder maintains several other radiation-related FAQs, for all your EMF FAQ needs. 8-)
--
"You've crossed my Line of Death!" "What? No! Where is it?" "Here in the fine print...."
By the way, I'm looking at only a partial T3 line (1.5Mbps) so I can pay a "low" monthly cost (compared to a full T3), while still being able to upgrade to higher speeds without having to upgrade equipment.
I just asked a friend of mine at a Tier 1 ISP what a T3 usually goes for, and he said it depends on how much you can schmooze the sales guy, but typically they go for anywhere between $30K and $40K...
alt3r3go
badges? we don't need no steenking badges!
Energy in a wave is directly proportional to frequency. One would expect higher energy waves (and therefore higher frequency waves) to pierce objects better. Perhaps you're thinking of diffraction, in which case low-frequency high-wavelength waves are better at going around corners/obstacles/etc. (but not through). Now someone, please correct me.
"If one is really a superior person, the fact is likely to leak out without too much assistance" -- John Andrew Holmes
Frequencies work differently in different media. For instance, high frequency is very good through the atmosphere. It'll blow right through almost anything. That's why FM radio only has a range of 50 miles or so (depends on the power of the transmitter). FM signals will generally pass right through the upper atmosphere, while the lower frequency AM signals will bounce off and extend the range a couple of hundred miles.
Low freqs work well in a more densely packed media, such as water. Sonar and underwater communications devices use low frequencys. Those signals carry over long distances because of the media they are travelling through, rather than because the signals themselves.
In Oklahoma a T3 from COX is approximately 30K/month.
Casca
First off, sound frequency is the frequency of vibration in a medium. Examples are voice in air and sonar in water.
Electromagnetic Frequency is the frequency of the EM wave. Examples are UV (suntan), Infrared (remote control), regular light, AM, and FM.
they are totally different!
Nearly OT but, on the topic of wireless transmission.... I've been searching around for a way to add ethernet connectivity to the computer that's going in my car (mp3s, gps, etc...). This microwave thing peaked my interest briefly, but I don't think it's what I need. I just need a range of about 10 feet and would settle for 1.5 Mbps. The only commercial solutions I've come across are >$200. Does anyone know of a cheap package for these slow, short range applications. Right now, I'm planning on going with my back-up plan: RJ45 in the grill.
Back to the point, packet BBS's evolved as a natural means to link distant areas and users in the same area over time. And with BBS's came people who wanted to buy and sell their gear and exchange the occaisonal dirty joke or file. All of which was against the rules, of course.
Surely, not the pandemonium of the internet, but it is interesting to note how the digital medium encourages bending the rules a bit.
--... ...-- -.. . -.- .. -.... -.-. --*-
Also, as the freq goes up the signals start acting more like light than fields, and things start wanting to work more point-to-point. That's one of the reasons I doubt you'll ever see cell phones at 26GHz: the directionality of the signals would be too great to allow you to just whip out your phone: you'd have to point it at the cell tower.
www.eFax.com are spammers
www.x.net.au - aims to build an australia-wide wireless WAN, im not sure how they plan to interconnect the access points, but it seems a mighty cool idea, since us aussies are usually volume limited with 56k modems too. also www.air.net.au, has some information have fun.
www.eFax.com are spammers
LATNET is a wireless network in Riga that's been up for around seven years now. This paper is the best resource you'll find on inexpensive wireless networks.
http://www.latnet.lv/LATNET /RADIOLink/HTMLDocument.html
Happy Reading.
Now, why did I keep italicizing baud? Because baud ain't bits per second! It one of my pet peeves when I hear somebody talking about his 33.6kbaud modem, or 56kbaud modem. There ain't such a thing! You have either a 3 kBaud modem or an 8 kBaud modem. A baud is a symbol transition per second, not a bit per second. In the old 300 baud days each symbol was worth 1 bit, so 300baud == 300 bits/second. However, in a 33.6kbit/sescond modem, the baud rate is 3 kbaud, with each symbol worth 11 bits. A 56kbps modem uses 8 kBaud, with 8 bits/symbol (with 1 bit robbed for line signaling).
On 2 meters, I could modulate a signal with C4FM (FM signal, but with 4 levels rather than 2) and get 2 bits/symbol, or 19200bps. If I went to 256QAM, I could get 8 bits per symbol, and still be perfectly legal. Why don't hams do this? Because you cannot hook an external TNC (terminal node controller, the radio equivelent of a modem+network interface) to a standard narrowband FM tranceiver and have it make those kinds of signals - you need a special data radio. Also, 256QAM has far less signal to noise ratio than does BFSK. Hence, the amateur community doesn't avail themselves of the bandwidth they have.
One final point: signal bandwidth does not directly control data bandwidth: as Shannon proved, it's all about signal to noise ratio. The only thing signal bandwidth does is give you a better S/N ratio.
www.eFax.com are spammers
actually, there is nothing specifically saying that you cannot use profanity over ham radio, it's more of a social code, where if you curse a lot, no one will want to talk to you.
So quick with fear you tiny fools!
Range limits related to frequency (especially in the SHF bands) are somewhat of a misnomer. You can apply the same principles to antennas provided that the antenna elements are in the same plane for your comparisons (vertical, horizontal, etc.). Once you start using a parabolic antenna (usually above 2.3 Ghz) there is one of those semi-obscure "laws" that come into effect regarding frequency vs. distance, and the standard thinking goes out the window. How about a 10Ghz CW shot from Russellville, Arkansas to Dallas, TX (roughly 200+ miles) pushing 4 watts into a 24 inch parabolic with a 599 +10 RST? Of course, (with some exceptions) any transmissions above 50 Mhz are line-of-sight anyway. 73 KK5WA
sine puella vita suget
The driver support under Linux for the WaveLAN card is fantastic, and the driver is even included with Linux-Mandrake 7.1 -- no special configuration required other than to make sure pcmcia inits before network.
The downside? It's not a 10-Mbps connection, it's only 2-Mbps. However, I routinely run X connections over SSH from a dedicated ssh gateway at my business. The link has fantastic uptime, the signal-noise ratio is almost as good as it gets with a 24dB antenna, and I'm completely undisturbed by power outages (UPS here), snow, rain, etc. High winds (60 m.p.h. + gusts outside right now) do take a toll, though. A 1 watt amplifier allows my 24dB antenna to punch right through the walls of my attic and lets me forget about the many trees, houses, and other obstructions between me and my ISP, 3 miles away.
The WaveLAN card with a pair of antennas and amps would be a much easier, more convenient option for most home users trying to set up this type of connection, IMHO. The amps are pretty expensive (a couple hundred dollars) but do wonders to ensure connection integrity.
Here's what my S/N ratio looks like, catting
Matthew P. Barnson
I learn what I think when I read what I write
The first issue, which a few people have mentioned, is that microwaves are LOS. On a lake with two mile range, that isn't really a problem.
The second is that developing high power in the microwave regions is very difficult. Note the quote of a 100 mW diode costing $45 in addition to the $90 cost of the rest of the unit. 100 mW isn't much power.
Fortunately, for link builders, the antenna size to achieve a given gain is proportional to the wavelength of the signal. In the case of this link, extremely high frequency means a very short wavelength and very high gain with not much of an antenna. A 1-2 foot dish will give incredible gain, but reduce your beamwidth to 5 degrees. (I don't have my ARRL Handbook with the exact quotes handy...)
retrorocket.o not found, launch anyway?
This link will take you to the data sheet.
$3,600 for 11Mb/s over 3.5 miles. We were just going about 500 yards, but right through some power lines and over an aligator-infested canal.
We only pay $550/month for our T1 with unlimited usage. I could have gone with a limited usage T1 for about $220/month!
p.s. Do you have any information where I can get a free counter for my website?
--
Have fun: Join D.N.A. (National Dyslexics Association)
These may be microwaves, but they're very low power. (Max 100 mW)
Compare this to the 500-1000 watts used by microwave ovens. Also, microwave ovens are specifically tuned to be absorbed at maximum efficiency by water.
retrorocket.o not found, launch anyway?
Expectations were that this could, quite quickly, result in a hot and tasty bird, even in the cool temperatures of Ottawa autumn.
I suspect the station manager nixed the idea; if it interrupted Max Keeping doing the news, there would doubtless be thousands of complaints...
If you're not part of the solution, you're part of the precipitate.
hypocrat: not found
hypocrite: hypocrite (hp-krt)
n.
A person given to hypocrisy.hypocrisy (h-pkr-s)
n., pl. hypocrisies.
The practice of professing beliefs, feelings, or virtues that one does not hold or possess; falseness.
An act or instance of such falseness.
One of the advantages of microwave frequencies, esp. the 10 GHz X-band used by the Gunnplexer, is the ability to build very small and very high gain antennas. You can easily get 20 - 30 dB of gain over an isotropic source with a small antenna.
First, i imagine the original design stopped at 2Mbps because it wasn't really feasable to go over that speed using the parts on hand.
Second, the statement about "not much operating at 2Mbps" as a reason for trying for 10Mbps makes it sound like he really doesn't understand the way asynchronous networks function.
At least with tcp, you simply transmit more and more (use larger and larger windows) until you start to experience transmission errors, or it just isn't getting you any better throughput, and then step one back from the last increase (well, you're supposed to) and call that your transmission rate.
Basically, the device on the other end ACK's every once in a while to let you know your packet got through. If the device on the other end didn't understand the data, or wasn't ready to recieve it, it can't ACK it. If you don't get your ACK in time, you retransmit. If you're having to retransmit too often, your transmission rate is obviously too high, so you back off your window size and slow down.
It's a cheezy form of bandwidth controll, but it works, sortof. It's the electronic equivalent of not reading a signifigant portion of your email in hopes that people will stop sending so much of it. Except that the protocol is designed such that a correctly written application *will* stop sending so much.
Yes, speed is nice. but relatively low-speed long haul links are the way the world goes round at this point. "T1" is only a 1.4Mbps link and it's more than enough for most corporate internet connections, even if the internal lan is 100Mbps.
The trick is, you have to remember that long haul links, no matter how fast, make really crappy bridges between homogenous networks. The segment length limitations are there for a reason. The speed of light is not just a plot complication in a larry niven novel.
The best way to handle a long haul link is to put a router on each end and let the routers deal with the general bullshit inherent in a really distant bridge.
Better yet, employ some form of traffic shaping (The buzzword is "QOS" but most people don't actually need or want guaranteed quality of service) in order to make sure that the pipe gets used to it's fullest capability rather than let applications choose their own window size and thus often cause the network to behave in a "bursty" manner, where a rude application or server occasionally kicks all other connections off the link for a few miliseconds so it can send it's data in first-class, and then let all the polite apps try and figure out if they can use a large window again.
The traffic controller code in recent 2.2 kernels is great for that kind of thing, btw.
Of course, as other people have pointed out, the legality of a 2Mbps HAM link, let alone 10Mbps, is quite suspect. Someone with access to recent FCC rulings should comment on it.
A licensed amateur may design and build their own device to transmit legally in the HAM bands, and it seems from the rules most people know about that the 10ghz HAM band is limited to 56kbps.
Consumer devices can use unlicensed frequencies such as the 900mhz range used by cordless phones and cellular devices, and the 2.4ghz range that's starting to be used by cordless and cellular devices, but this requires that the design of the device be FCC approved, not an easy thing for joe solderingiron to acheive.
It's posible to use a licensed frequency for high speed data transmission of just about anything you like, but this also requires an FCC approved design.
Is there anyone here who's recently researched FCC rules regarding packet data rates?
This is just like television, only you can see much further.
Now i can tap into my work OC3 from home. Definately have to look into this one.
How would this be even as secure as wireless phones? (And we've all got some idea of how secure those can be.) At least with fiber or wire you need proximity...
Do something about world hunger. Click here
So far, all it says is that he is still waiting for his book on Ham radio to arrive. There are no instructions yet.
---
Zardoz has spoken!
Oper on the Nightstar
but I assume this requires a direct line of sight, am I right?
Still, the last company I worked at had a microwave link between 2 offices that cost about 5,000 to install, and only ran at about 1 or 2MB/s, if I recall. I guess it wouln't really matter for a business, though, since amateur radio cannot be used for commercial purposes.
Anyone know how hard it would be to extend this to, say, 6 miles?
What I'd like to do with one of these suckers is get my friends together and start building our own backbone, free of government iinterference and snooping. No NSA members allowed.
Don't think that it wouldn't be useful, either - between us we have thousands of MP3s.
And, if we could share a fat pipe (T3?) to the internet through a bunch of members carrying the cost....
Drool.
No comment at this time
http://www.qsl.net/ke5fx/uwave.html
Definately something to watch, though. Maybe I can get my neighbor to get DSL and then beam it over microwave to me (I'm a little too far...)
dc
--
Wooden armaments to battle your imaginary foes!
www.isp-lists.com, join the isp-wireless discussion, and READ THE ARCHIVES. Figure out what equipment you want, buy it and play with it. I chose lucent becauase of the 11mbps, most are only 2. Also lucent/orinoco has better software.
You can get info on equipment from www.wavelan.com, and actual equipment from many places, www.winncom.com is good, and has good prices. I get antenna's and amps from www.ydi.com
This is getting to be old hat. There are plenty of products out there, including those already mentioned. The company I work for here in Detroit is using Breezecom's 11 mbps DS.11 gear to do exactly what's described in the article. The only thing we're having trouble with is local zoning to build the 80' tower necessary to get the antennas between the two sites 2.9 miles apart. One site has three buildings within 500' of each other, which will be tied together with the 11 mbps radios, the other site has seven buildings over a square quarter-mile. We've got the antennas hung on all the buildings and are awaiting the client to pull power and ethernet to each radio. Can't wait to see how it all comes out, especially whether or not the city/township boards will approve the antenna tower designs.
Most Ham's seem hell bent on destroying COMMUNICATION not improveing it Competant electronics men are walking around w/o a 'card' because of a mild dyslexia they can no longer do code.[I know they eased the standards SOMEWHAT, it still isn't enough to put free speech in the hands of anyone capable of building a hi Q rig that would fit into the band w/ minimal harmonics.] Those that get licenses find themselves drowned out by a bunch of high powered rigs doing communication checks w/ the KING OF JOURDAN [have you got yer postcard yet]. [ He was a nice guy who would have wanted to strangle him?] More importantly, I've never heard of anyone threatening to report injustice or genicide to the international RELAY League the way they make posts to the internet. Aside from a few instances where the hams have provided info on natural disasters, they have generally squashed freedom under their unimaginative butts. Now the Ham community wants to compound the the trouble of the net w/regard to government censorship by patching the bandwidth together with complicated interlocking -wave systems. KIDS with little $10 dollar e diaries, can send messages down the block with a couple of dammed diodes & these guys want to pollute the neighborhood with UNECCASSARY leakage. The idea ought to be to increase the simplicity, like talking accross town with neon diodes [in broad daylight, UNREGULATED VISIBLE LIGHT]. To create one way, non interlocked, browsers that don't require a lan net to commo two machines. If you guys want to use enough power to fry your pancreas in order to send a web page; the same thing that a kid is probably going to do with 2 aaa batteries be your own guest, but don't kid me or yourself in what your doing to communications. One day the world will be linked with cheap laser units, no optical fibers or or T&Ts just simple , uncensorable, infinite bandwidth available to all for a coupla bucks.
I believe the original specs from N6GN indicated that even the 100 mW transmitters could probably reach 40 miles with a good LOS. (Of course, getting that good an LOS is TOUGH. You'd need VERY tall towers and no hills in between.)
retrorocket.o not found, launch anyway?
If your best reception on a sunny day is 2 miles, then it can decrease quite a bit during small events like rainstorms, etc. Of course, you need to be extra carful about lightning, and I'm not sure how that problem is handled in microwave towers.
my own practical experience with this comes from being a radar tech in the military, but your milage may vary. after all, the freqs may be different, etc.
"It is a greater offense to steal men's labor, than their clothes"
This project is prety non-informative at this point. C'mon, how about linking to his page after he reads his Microwave Data Link for Dummies(TM) handbook.
--
Have fun: Join D.N.A. (National Dyslexics Association)
When was this announced?
I do recall that 56k was the limit in the 440 band, but I haven't head of 56k limits in higher bands. (I think most of them have some limit, but higher than 56k once you get above 1 GHz.)
retrorocket.o not found, launch anyway?
I'd be really impressed if it was that cheap.
You could probably get the pc cards for $500, but then there are the bridges, antennas and cables...
A tiny one-page site with about 5,500 hits total, and its standing up to the slashdot effect just fine!
But seriously, this is a great idea. I would love to try this.
No, Thursday's out. How about never - is never good for you?
It links to the same design this project links to.
retrorocket.o not found, launch anyway?
Wireless Ethernet has become so cheap and available, I'm not sure what the point is? Check out Lucent/Wavelan's offerings. For about $500US, I can get two PCMCIA cards, PCI bridges, and powered antennas that can do a couple of miles.
Check out http://www.wavelan.com/.
-buffy
When trying to determine if a license is necessary for transmitting on any given frequency, you have to look at the FCC regulations for that part of the radio spectrum. In general, there is nowhere that you have free reign to transmit anything you want. This is a very old problem whose solution is well known. They tried the free-for-all thing 100 years ago when radio was new and found that everyone just interferes with each other and can't do anything, unless they group similar users in certain bands (frequency ranges) of the radio spectrum. So there's a reason why they do that.
On Amateur Radio frequencies, you need an Amateur Radio license. They're not hard to get. Dave lists a good start on his web page on how to study to get one.
On 802.11 Wireless Ethernet, you have to stay on low power to avoid interfering with the licensed users of those frequencies. So even though you don't have a license, that's the condition under which you may transmit. Other commercial uses require commercial licenses that you probably can't afford for a hobby project.
Don't just flaunt the rules. You'll undoubtedly end up interfering with someone who belongs there, which just isn't nice. It may take them a lot of work to find you and they won't be happy when they do because of all the work you caused them. And the FCC started doing enforcement again last year after neglecting it since 1993. Some people are still of the attitude that there's no enforcement. They won't accept ignorance as a defense.
I'm not sure this is completely on-topic, but I wanted to mention that here in Israel, microwave radiation is the center of a lot of attention now.
It seems that a lot of research suggests this is likely to be one of the more central causes of cancer amongst Modern civilization.
The cell-phone companies around here have to hide antennas all over the cities, because they are simply not given the licenses to install such antennas.
Israel was boomed with cell-phone (microwave-based) communication, and it seems as one of the only places to start taking its effects on the health seriously.
Is it truly that dangerous, or just unjustified panic?
True, we are all gonna die...
"It takes many nails to build a crib, but one screw to fill it."
Much communication today is taking place by means of microwaves already. A microwave oven uses microwaves of a frequency that excites (heats) water. It doesn't take nearly as much power to communicate as to cook, but I still wouldn't want to be too near when it's working.
no big sig
I do have to say, I really enjoyed reading your project(back a few months ago, someone linked it off of /. in the comments.)
I was seriously considering setting up something like that, but I still have to wonder how safe it really would be. It seems as if it would not too major of a concern,(note that this would have been in my bedroom, however) but I don't know that I would want microwave radiation there all the time. Anyways,though, money ran out, and - long story short, I didn't build them(probably better that way, considering the dificulty of them-- I'd probably still be working on them.)
Kudos for the cool write-up on them, though. Maybe someday I'll get that going, just for the fun of it.
If I was that drunk, I would have remembered it -- H. Simpson
why can't you crypt it? Say you use this for email, do you want the entire world "packet sniffing" on your converastions?
Given the insecure nature of shooting you data out into waves avaiable for anyone to listen to, there should be some legal way to secure this...
Maybe "incode" all your senastive information into "quake3 packets"?
"`Ford, you're turning into a penguin. Stop it.'" -THHGTTG
Ok, this is cool, but now how about a guide called "how to convince your work to let you put an antenna on the roof" so I can tap into our 8 T1s instead of paying $100 a month for lousy DSL service?!? Hmm, I wonder if it would work through a window..
Seriously, unless you are very careful, microwaves are extremely dangerous.
I don't know how many of you have been shocked by 110v, but I can attest to the fact that I would rather spend an hour with 110 going through my body than even spending a single second getting a burn from RF.
So, please know what you are doing before you attempt to build something like this. Even standing in the wrong place with relation to the feedhorn is enough to make you sterile in nothing flat, if not cook you from the inside out.
the infrared transmitters could go through buildings
Infrared can't penetrate several pieces of paper, let alone buildings. Infrared is just below visible light in the frequency spectrum, at about 70 terahertz.
The higher you go with frequencies, the more bandwidth you can easily get. (Exceptions are TV broadcasters, who somehow managed to swindle the FCC out of 6mhz per channel in the 55 through 800mhz range). The more bandwidth, the more clarity (perhaps what you meant by "less interference") you can encode in whatever digital encoding scheme you're using. However, the signal also gets more directional and starts to not penetrate things (like raindrops and trees). HF (signals below about 30mhz, this includes shortwave) can be reflected by the atmosphere and travel around the world (depending on conditions and the specific band you're using). VHF/UHF (30mhz to about 1ghz) will go through hills/concrete structures/etc usually, but there's not much bandwidth left in the VHF/UHF range for people wanting to set up 2mbps links to their friends. Microwave (1GHz on up) has plenty of room, but the signals can't penetrate much.
Robert Woodcock, KC7WOZ
I read your (original) project-document, and I was very impressed -- as both a ham, and a veteran of (one of) the original GPS receiving systems (Magnavox, 1981-3). I left the microwave field after the late 1980s, when everyone (who worked in the Govt. Aerospace industry) found themselves jobless. (Today, computers pay my bills.) Many simply do not understand the philosophy of microwave technology (and the "rf-mindset," in general). "Doing it the right way" is always a chore. ('Strays' & 'parasitics' are unfathomable to most.) Moreover, even the more recently licensed amateurs have the tendency to view their equipment as toys -- not as 'platforms for creativity, and expansion of one's knowledge.' You've done everything right, and there are those who realize it. Keep up the good work, O.M. 73s... ...DE N6BHU
...DE N6BHU
Didn't even catch that link.
My bad.
--Kevin
=-=-=
l0pht has had a wireless LAN (guerilla.net) project for quite some time now.
t .html
http://www.l0pht.com/~oblivion/radionet/radione
[Connection closed by foreign host]
...is his domain name. What a great way to get back all those nice, short domain names! Too bad underscores aren't legal.
- No profanity
- No music
- Nothing remotely commercial
- No encryption
After all, it's a privilege to generate an electromagnetic field...--Just the place for a snark!
"Geeks worldwide cook neighbors with kit found on evilnet (aka internet)"
All kidding aside, I wonder if my ISP would let me set one of these up between the local POP and my house.
One of the unfortunate drawbacks to high-speed wireless data transmission, especially in the 10mbps range, is the tradeoff of frequency vs. transmission range. (I'm pulling this all from memory of a conference I attended on wireless data transmission, please correct me if I'm wrong). The problem is that high bandwidth wireless pipes (microwave) require very high transmission frequencies, typically in the 2.x GHz range IIRC. Waveforms with high frequencies have short wavelength, and therefore do not travel far, or through objects (in the same way that you can hear the bass from your neighbor's stereo, but not the treble).
Unless this technology has advanced substantially in recent years, most microwave transmitters require line-of-sight, and rarely transmit more than a few miles. An ISP I used to work for purchased a set of microwave transmitters to allow them to expand their business into a neighboring state without paying taxes and tarrifs on a leased line crossing state borders. The band these microwave transmitters use isn't retulated by the FCC, so transmission at those frequencies is open game. We had to set up the transmitters on opposite sides of the border (a few miles apart), and align them for line of sight. Even at a short range, we still only got E1 speeds (which I understand to be ~2mpbs).
alt3r3go
badges? we don't need no steenking badges!