I live in a small village which doesn't have broadband internet. The nearest two towns both have ADSL at 2Mbps and I am thinking of getting connected via a wireless connection.
There are several comanies which sell 2.4Ghz antennas and some claim distances of up 12KM when using directional antennas point to point.
Has anyone tried setting up a reliable 802.11b or g connection over 5KM or more.
I've seen long range wireless links work fine (20km+) so 5km shouldn't be a problem. Just make sure you have line of sight and 2 directional antennas (grid, cantenna, yagi etc)
Does anyone have any tips on aligning the antennas?
After setting the direction generally, a friend of mine fine tuned the alignment of his (shorter distance) link by connecting his laptop to the AP and pinging the other end. He would move the antenna and see if the roundtrip ms went up or down.
Is there any other tips on doing this. Over 5KMs I guess small movements of the antenna can make big differences.
Sneeze and your wifi link will drop:-) You need to look at the Fresnel Zone for this as that distance you will end up with curvature issues...though minimal you have to make sure that you don't end up with anything in the way and that info will help to get you where you need to be. Use really high gain directional antennas and good quality gear. I'd google "wifi, fresnel zone" and there is a couple articles on it there...
I am on a local WiFi internet service that claims to shoot 11-15 miles with good line of sight. They are shooting from towers on hills into the valley floor though.
I have done most of my links at over 5km using 400mw 802.11b cards with 12db mini and the other end 200mw Senao and 19db grids at the other end.
Can pull an easy 3-4MB at 7Km (limited by the router load control)
Best link was 42km and 46% link strength.
Signal been detected at 80KM+ at -91db (must give it a test at some stage)
In a nutshell if you have the right gear and set it up right it can be done.
Links like this are best aligned using software on a laptop.... no guessing here.
You don't really have to worry about earth bulge until about 10km. 2.4 Ghz at 5km you need at least 12.4 metres height to have a completely clear Fresnel zone, this is from the centre of line of sight. You can have up to 60% Fresnel zone blocked theoreticaly which would be 7.43 metres, but I wouldn't recommend it.
Next is the anttenuation of the signal for 5 km is about 114.21dB so from there you can work out your radios and antenna.
example useing Senao 200mW (23dBm) radios with 19dBi grids.
Assume loss of 10dB for cables and connecotrs.
23 + 23 +19 +19 - 10 - 114.21 = -40.21dbm
This would be heaps to have a 5-11 Mb link even witha fade margin of 15dB
We had 10Km link with Senao 200mW, but with 5Mbit. Then we've installed D-Link DWL-2100 with my hacked firmware and now have 45 real Mbits!
At 17km link we've got 35 Mbit. It's like a dream Super high speed lnik cost about 100$ for 2xDWL-2100AP
We had 10Km link with Senao 200mW, but with 5Mbit. Then we've installed D-Link DWL-2100 with my hacked firmware and now have 45 real Mbits!
At 17km link we've got 35 Mbit. It's like a dream Super high speed lnik cost about 100$ for 2xDWL-2100AP
Could give a information about your hacked software?
5km is no worries provided you have good line of sight. Look for antennae with at least 15dBi of gain (more is generally better). Keep the antenna cable runs short and you will find most off the shelf gear will happily pull the distance.
If you use two of the same model of access point, set them up in bridge mode if possible to improve the efficiency of the network and eliminate a few flaws you can encounter using regular 802.11 infrastructure networks.
Try comparing various models of access point and look for models that offer higer transmit power and receive sensitivity (the latter is often overlooked, if they don't publish the specs then walk away).
Does anyone have any tips on aligning the antennas?
This tool reads signal levels from a DWL-2100 wireless client and access point/repeater also DWL-2100 and speaks the measurement. Another cool feature is the client signal graph from the access point side.
Find both ends in GOOGLE EARTH. Placemark both locations. Note both longitudes and latitudes. Scroll out so you can see both ends and draw a path. This path will give you the choice of reading distance in miles or KM. Do a screen capture. Print the image out, preferably on a color printer.Continue this line in both directions with a pencil. Look for landmarks to point your antennas at for coarse adjustment. Measure the angle with a protractor.
Is 5KM possible? 
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