Equipment for Outdoor Wireless Bridge

J

joblo37pam

2[H]4U
Joined
Jun 28, 2002
Messages
2,211
I'm looking to set up a wireless bridge between my office and house so I can keep an eye on things a litte easier (and only have to pay for one connection). I just can't decide what equipment to use.

I've been looking at this: http://www.newegg.com/Product/Product.aspx?Item=N82E16833168009
(or the 16dbi '+' version), but looking at the datasheet, it is only rated to -20c (-4f). Around here, there are a few times in the year that we drop to -20f or so. I've seen other outdoor APs that have built in heaters, but this model doesn't seem to.

The two buildings are ~1mile apart, and if I mount these on the roof, there isn't many obstructions. I'd like to get something that will do this reliably with good connection speed, but don't want to spend a fortune to do it. If anyone has any experience with outdoor APs, your opinion would be appreciated. Thanks
 
Feature wise, it’s fine.

At 1 mile with a 9dBi antenna you will only need 250mW for a good link, so you have enough power. The 16dBi would help you with a tighter beam-width, (less interference) but it’s connectorized so you could change over to an external antenna if you need to later.

If you’re mounting it on a roof you’ll want grounding for the AP and surge protection for the Cat5.
I use #6 wire to an 8’ ground rod, bonded to my service ground rod at the meter. Grounding the AP is not only for lightning, it’s also for draining off static charges that can build up from the plastic enclosures in high winds. Otherwise they drain through the circuit board.

As for the –20C rating, it may be close enough. If you have problems you could buy a heater.

Go for it.
 
Those Engenius APs are not to bad, I have used them in the past, there are better APs, but not for the price, they tend to be very sensitive, which is very good on long distance links.. If you have line of sight at 1mi, that is an easy link and this will work no issue..... LOS is everything, way more then even power, with this type of AP 8-11miles in the field is pretty doable.....
 
It's not perfect LOS, there's a small hill in the way, but from rooftop to rooftop I will clear most trees and buildings. Newegg evidently doesn't carry the 16dbi version anymore. I've read plenty of good things about these as long as you don't crank the power too high for too long, but I'm more concerned with the weather. I don't see where engenius makes a heater for this model, and the POE injectors don't push out much current to make something myself.

Edit: What type of realistic throughput do you think I can get with these? Ideally I'd be able to stream some HD content over it, but that may not be a realistic goal.
 
I have heat is the problem, they run HOT, the winter is usually the most stable months around here, summer tends to bring them down to their knees.....
 
gjvrieze said:
I have heat is the problem, they run HOT, the winter is usually the most stable months around here, summer tends to bring them down to their knees.....
Click to expand...

Ok, well it gets to `110F around here, too. Supposedly that's within spec. Do you have power set to 'extreme'?
 
joblo37pam said:
Ok, well it gets to `110F around here, too. Supposedly that's within spec. Do you have power set to 'extreme'?
Click to expand...

On "extreme" they get super hot even in an air conditioned building in the summer just siting on the bench, I have no idea how bad it could be in 110F, but if it was ever in the shade, I am sure that would help out, and order from like Newegg, so you have warranty, then it is not as important if it only lasts 1-2 years......

I actually just shoot you a PM....
 
“There's a small hill in the way”

That can change things. LOS as the radios see it includes the Fresnel Zone, it’s shape looks more like if you took the Hindenburg and stretched it between the two antennas. Any object inside the zone has the possibility to break the link depending on its RF reflectivity. Grass and trees absorb RF, buildings, cars and more dense objects reflect it.
Basically, the radio sees it as a second wave arriving out of phase from the original.

What you would be concerned with is any object or obstruction within 60% of the first Fresnel.
At the mid point of a 1-mile link it would be a 14-foot radius around the beam-line between the two antennas. With a calculator, you can see that at .2 miles from the antenna it’s still around 11ft. in radius.

Depending on your path between antennas may or may not be a link-breaker but the only way to find out is by testing the link, and that means buying some radios.
Ways of solving that problem would be to put one or both radios on roof masts, up to, using a TV antenna tower to mount on. Most building codes allow up to 20’ above the highest point on a structure without having to file for permit.

It’s best you know this now rather than $2000 later that there may have been less expensive solutions to the original goal.

As for weather, hard rain and snow have little effect; on rare occasion a temperature inversion may cause some fluctuation in signal strength.
I’ll have to dig for the info on the heater. From what I recall, it’s around $20, mounts inside the enclosure and would probably need a separate power supply.
 
I'm aware the hill is going to cause some degredation, but if the AP is pushing 400mw through a 16dbi antenna, it's really overkill anyway. As far as beamwidth, engenius actually publishes the theoreticals here: http://www.engeniustech.com/resources/16dBi_PATTERN.pdf

I'm actually reconsidering using directionals on both ends of this. It may be more useful for me if I used a decent omni at the office, and then a directional bridge at the house. That would give me the flexibility to connect back to the office from the majority of my client locations and at home. The town that I serve is almost perfectly 1sq mi, so it shouldn't be too hard.
 
joblo37pam said:
I'm actually reconsidering using directionals on both ends of this. It may be more useful for me if I used a decent omni at the office, and then a directional bridge at the house. That would give me the flexibility to connect back to the office from the majority of my client locations and at home. The town that I serve is almost perfectly 1sq mi, so it shouldn't be too hard.
Click to expand...

Very good idea, I have found that the client site AP is by far the most important, as RX is easy, but TX on weak antenna can really bring network traffic to the ground.....
 
If the weather is really going to be that big of a problem with these, maybe I would be better off to house the APs inside (attic, suspended ceiling), and just mount antennas outside? That adds some cost to the project, but if it's more reliable it may be worth it.
 
joblo37pam said:
If the weather is really going to be that big of a problem with these, maybe I would be better off to house the APs inside (attic, suspended ceiling), and just mount antennas outside? That adds some cost to the project, but if it's more reliable it may be worth it.
Click to expand...

The big problem, is that pulling LMR400-800 cable is $$$ and a lot of work, and it adds line loss, with the AP hooked directly to the antenna, via a small pig tail, there is soo little loss......
 
Also, most attics aren't heated? How would being placed there help against the frigid temps?
 
GlobalFear said:
Also, most attics aren't heated? How would being placed there help against the frigid temps?
Click to expand...

They may not be heated, but it's still 20-30 deg warmer there than it is outside, especially if you consider wind chill/ice buildup, etc. It should be enough to bring within specs.

what kind of range can I expect from one of the 400mw engenius aps strapped to a 15dbi omni?
 
joblo37pam said:
They may not be heated, but it's still 20-30 deg warmer there than it is outside, especially if you consider wind chill/ice buildup, etc. It should be enough to bring within specs.

what kind of range can I expect from one of the 400mw engenius aps strapped to a 15dbi omni?
Click to expand...

At 100ft off the ground, it is something like 14.4miles, and at 200ft, (going from memory, do not have the chart in front of me) it is around 20miles, basically, you hit the curvature of the earth and do not have LOS after so far....

EDIT, actually, I found the chart:

http://www.wirelessantwerpen.be/events/28052003/RF_Calculator.xls
 
You must log in or register to reply here.
Back
Top