Will an Omni work with Directional Antenna

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So i've not very knowledgeable of the Wireless & Networking field in general. I've only done very basic networks and bridges. But I've been trying to get internet in a remote area about 4 miles (4.9 miles to buddies house if you go straight through trees/hills) from the nearest town that has Cable internet for awhile now. No one seems to want to run a cable out there.

So my question basically is if it's possible to beam a wifi signal over that distance with heavy obstructions such as Hills & Trees.

Here's a poorly made Paint picture of what i was curious about if it could be done.
fcb236f154.png


Additional information: The 2 sites i want to go from (A to B) are A: 244m elevation to B: 264m elevation with a peak mountain of 311m elevation in the middle of the 2 spots.
 
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Tabris DarkPeace

Tabris DarkPeace

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1) The directional points at the sky.
2) The omni has no line of sight to the directional in that picture due to it being in the shadow of a hill. (and vice versa)
3) You provided height data without co-ordinates for each point, making it somewhat awkward to 'guess' instead of figure out.

Likely Problems: Even if the omni can receive from the directional it might not be powerful enough to transmit back to it without major problems.

It's not impossible, if the hill is redrawn, or there is actually line-of-sight for some reason not outlined in your initial description.

Alternatively: You could bounce a signal off the stratosphere, but that goes well beyond most DIY kits, have higher latency, noise, etc and might not be 100% legal. :p

There's probably at least two other solutions that would work without Line-of-Sight but I doubt they're legal, or easy, or cheap, or a combination of the former.

Thinking about it practically, instead of as a triangle where nothing can move, it depends on the elevation of either, or both, of the antennae.

e.g. You may be able to have the directional on a very tall tower. (like your drawing suggests).


As for the omni vs directional argument it depends on the attenuation or signal loss. For all I know the directional antennae is worse than the omnidirectional one. You haven't listed the power output of either, nor the protocols used, etc, etc, etc.

 
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Tabris DarkPeace

Tabris DarkPeace

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*** UPDATE - FIXED THE DB FIGURES ***:

Looking at the WiFi power info the gain required would be around ~ +16.2 dB (I think) give or take. Maybe slightly less. Assuming your WiFi network would work if it was within 600m of each other (at the lowest permissible WiFi 'carrier' speed).

If you WiFi would only work without extra equipment at 300m then add +2.7dB to +3.1dB, at 150dB, another +2.7 to +3.1dB (and so on). Or subtract if it works at 1200m, etc.

Anything less than +18.9dB gain I wouldn't suggest though, and frankly I think it would be asking far too much of the omnidirectional WiFi router. :(

- You can probably get +11dB omnidirectional antennae, not sure if you can get them specifically for WiFi though. They just trade one axis for gain instead of two.

Now, I am pretty sure you can buy antennae with even more gain than that; possibly even omni-directional ones. (Not sure from where, but they do exist somewhere).

For every halving or doubling of the 'working range without extra equipment being required' subtract, or add, about +2.7 to +3.1 dB gain.

Test each router together in an open field somehow and see what range they will connect at doing say 11 Mbps. From there you have a starting point.
+ Also post their specs.

Of course it would be more practical to 'borrow' one of the other bands with a higher power output allowance (depending on the country you're in). Such as citizens band radio, or FM, or ham radio (which can be insanely powerful). 'Broadcast' away, then reverse it at the other end. (Basically like an amplifier).


P.S. I am not a professional at this but I can crunch the numbers and give what I feel is a fairly good indication of whether or not it is practical or not. Costs, ease of set-up and 100% legality of the solution totally thrown out the window here. ;-)
 
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I actually don't own any powerful antenna's at the moment or any of the equipment i'd require for such a task. I'm trying to figure out if it's even possible to have hope of successfully pulling it off. I've been looking at some of Ubiquiti network's AirMax hardware, I wasn't looking to spend a fortune but rather see if I'd be able to pull it off with the right equipment.

But referring to your bouncing suggestion. I actually am able to see a cell phone tower at both locations if i'm high enough, although the tower is about 10 miles away from point A and maybe 5 from point B. I was curious myself if that would work but that may just be wishful thinking.


Now this may be a useless picture but i used Ubiquiti's Outdoor wireless calculator and tried to setup a network with the AirGrid M2-20dbi having point A @ 120f off the ground and point B 50ft.

a54349fdea.jpg



EDIT: On a minor note, I am able to obtain a 4G signal on my phone at times for internet data plan useage but as with any (as far as i know) cell phone data plans you can't exactly use this for much on the internet seeing as it's very limited (3gb/month) type thing.
 
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bill001g

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If you had clear line of site maybe it would work. You likely would have to exceed the legal broadcast power on the omni side. Directional antenna at that range would work well though......again assuming clear line of site.

I suspect you cannot get this to work with any form of unlicensed equipment. The standard 2.4g and 5g are blocked by simple trees leaves and you need to be way above the ground when you are going those distances. You can also use 900mhz unlicensed and that will tolerate trees a little better and the ground does not absorb as much but a hill of dirt will still block the signal since it too is line of site.

The only chance you have would be to get a amateur radio license so you could use the much lower frequencies. You will be limited to fairly slow speeds though.
 
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bill001g

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Didn't see your other post. You could if you paid enough put a back to back pair of directional antenna on the tower like the ubiquiti you mentioned and it might work. Power would work for sure but passive might also.

They charge way more than you can likely afford to put antenna on towers. You could most likely pay to have a private line internet run to the house for less than the tower space rental.
 
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