huf67
join:2002-08-19
Terre Haute, IN
 ·RoadRunner Cable
| Long Distance WiFi
I'm trying to share my cable connection with a friend of mine that lives about 5.8 miles as the crow flies according to Google Earth. I've got a 24dbi grid antenna that I will be putting up on a 50ft tower. I am using a Linksys WRT54GS router using DD-WRT firmware. And I may put a 1 watt in-line amp if need be. I've got a 19dbi Yagi antenna for his end but I'm not sure what type of wireless card I want to use on his end. I've read about mini-pci wireless cards boosting 600mw but I'm not sure if they will fit into a regular pci slot. I've never heard of a mini-pci slot on a motherboard. I've got a 10mb down and 1mb up connection.
What I would like to know does anyone think this is a plausible project ?? I've read on different sites about 'line of site' but does this mean that if you don't have direct line of sight that it wont work at all ?? And I've also read about the Fresnel effect in which the radio signal goes in an arc so I'm thinking this project might work. I understand that he's not going to get the speeds that I have but he's on dial-up so anythings got to be better.
Also I would like to know what's the farthest wireless connection any of you have achieved and what kind of setup were you using. |
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SipSizzurp
Time to switch hands.
Premium
join:2005-12-28
Hilo, HI
·RoadRunner Cable
| 6 miles with line of sight is easy. Asking whether or not you can do it with partial line of sight is like asking if you have enough gasoline to make it to Kentucky, and you are not quite sure where you are currently, or how much gas you have in the barrels. |
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LLigetfa
join:2006-05-15
Fort Frances, ON | I think you should have a router on the other side as well and not just a client card. |
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stevech0
join:2006-09-17
San Diego, CA
edit:
May 3rd, @02:25AM
| reply to huf67
I doubt it'll work, for 6 miles. Especially at 2.4GHz due to interference. Long links in unlicensed band are more often done at 5.8GHz with 802.11a or a proprietary method such as TDD.
with the 50 ft tower, do you have line of sight to the far end? If not, unlikely it'll work.
What's the elevation at the far end? IF it's not well above the treetops and buildings in the line of sight path, unlikely the link will work.
Both ends need to clear the so-called Fresnel zone. Imagine a football-shaped thing touching each of the two antennas. The fatness of the football depends of path length (and frequency). If too much of that football is blocked by trees/buildings, you'll get a too-weak signal. This can be calculated if you know what the line of sight conditions are.
Amplifiers: Do very little good unless BOTH ends have the same transmitted power. I hear you but you don't hear me. And the bi-directional amplifiers raise the noise floor of the receiver excessively.
Again, this is done every day with a bit of planning and math, and some software tools. But rarely in 2.4GHz, esp. in suburban areas.
Best way to do this is with a pair of wireless bridges from Demarc Tech, Deliberent, or equivalent. These are about $150 each.
The 24dBi mesh parabolic antenna you have is nice, but you must put the wifi device atop the tower, else the coax to the bottom will attenuate the signal too much. The outdoor bridges I mentioned above have no coax; integral antennas, for this reason. And their radios are designed for the temperature extremes outdoors.
and keeping the 24dBi dish aimed correctly over a long time can be difficult as it has a very narrow beamwidth. Gotta have really good mechanicals and tower stability. The wireless bridges have 14dBi or so and are less critical, but get the same radiated power via special radios for the purpose. |
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huf67
join:2002-08-19
Terre Haute, IN
·RoadRunner Cable
| reply to huf67
Thanks for all the advice. I just got my LMR-400 cable today and I'm gonna at least make a go of it. I've got to much money wrapped up in this so far to just quit. My buddy knows that this might not work.
One other thing that I might so is put one of the solar powered repeaters from Meraki on the roof of the place where I work at. It's about 150 feet high and directly inline with my house and my buddies house.
It's worth a shot !! |
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stevech0
join:2006-09-17
San Diego, CA | your buddy cannot get cable/DSL? |
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Killler Maxxx
@rr.com
| said by stevech0  :your buddy cannot get cable/DSL? They are gonna start a WISP and are figuring out how to hook up clients. |
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stevech0
join:2006-09-17
San Diego, CA | well, they and you will need more expertise to be a WISP. |
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