Wireless Bridge - 3mile/4.8km

[njxc500]

I'm looking at setting up a wireless bridge. I've got pretty good line of sight, but I'm not sure how much tolerance there is with this.

I'm looking at a Ubiquiti PBE-5ac-500 to set this up. Has anyone used one of these? I have a relatively short link, but I'm interested in getting some serious throughput for streaming.

Thanks

 

[digitaldoc]

A 3 mile bridge is possible, but it needs solid line of sight. On top of that, it needs to be lined up well for it to function. It can also be effected by weather. At that distance this is going to be unforgiving, especially if you are looking for streaming speeds.

 

[bill001g]

I have used other ubiquiti stuff and it is pretty easy to setup and use. I suspect your largest issue is going to be what is called fresnel zone.

The clear line of sight is actually much more complex than just being able to see the device. When you go long distances the beam spreads and if something in the path disrupts that beam it can degrade the signal. So your complete beam must have clear line of sight not just the center of the beam. These are very weak signals so it does not take a lot to disrupt them.

When you feed the number into a fresnel zone calculator for 3 miles on 5g you get about 25ft. This means you must be 25ft above any object in the path. So on flat ground you would need to be up 25ft. If you have a 20ft building in the path you must be 25ft above the 20ft or 45ft. This is actually a over simplification but when you try to go long distance you need to be very high up on both ends to really get it to work.

Now it may work at a degraded rate if you put it lower but that is impossible to actually predict. I know from the ones I have installed we get no signal at all holding them at ground level even though we can see the other unit with binoculars but even 10ft up you start to get some signal.