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New Member
Posts: 11
Registered: ‎07-14-2017

Beam spread Question

Installing an M900 airbridge. Access point is .83 miles from the station and is approx 24' off the ground. The station is 30' off the ground. How much can the vertical adjustment on the antenna bracket have on the beam width and the possibility of an beam over shoot on either side? If by accident one or the other or both are set at ten degrees up, could this effect connection quality?

 

thank you for your help.

Ubiquiti Employee
Posts: 910
Registered: ‎04-14-2017
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Re: Beam spread Question

@UBNT-Nick Please take a look.
Ubiquiti Employee
Posts: 47
Registered: ‎02-13-2017
Kudos: 24
Solutions: 5

Re: Beam spread Question

If you aim both devices too high you will not get the best signal. You will need to point the first one the best you can, install the second and get the best possible signal, then go back to the first to realign.

It would also be worth the second trip to the far side of the link to double check the alignment there again too.

New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

Thank you, Nick. I have set the Access to 0 degrees and now I am getting a fair connection. I have not been able to do the station yet because it requires a lift to reach it at 38ft. I have attached screen shots of both the access and station. I would love some feedback.

Access.jpg
station.jpg
Ubiquiti Employee
Posts: 47
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Solutions: 5

Re: Beam spread Question

It's good that you have it connected, but it is a pretty poor connection. Alignment may be way off. I definitely suggest you double check the alignment when you get a chance.

Is this shooting through several trees?

You may need to upgrade to the Rocket M900 with a yagi on both ends to get better results.
New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

This is the best signal I have gotten in two weeks. I think the one dish was pointed up too high and over shooting. I need to check the station and see what it is set at I guess.

It is shooting through a few trees, yes. I thought the Nanobridge M900 was good with a few trees. Hmm. Now do the altitudes of the two antennas have to be spot on to get a good signal?

 

New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

[ Edited ]

@UBNT-Nick We just discovered that the access point altitude is 3753ft and the station is sitting at 3772ft or 20ft above the access point. Could this attribute to our problem? Btw I tightened the bandwidth to 10Mhz.and managed to get a solid 3.25 tx and rx

New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

Before I rent another lift and waste a 8 hours in the sun can anyone look at my situation and tell if I altitude of the two antennas being off by 20' will make a difference in my weak signal or should I bag the M900s, send them back to Amazon and purchase something different? The only way I can do this is next week so I have to plan ahead.

Please help.

SuperUser
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Re: Beam spread Question

Is there a hill in the way??????

 

If there is, you must aim up the hill on both sides.  Your signal doesn't make sense for such a short distance.  You should be getting much stronger signals.   Check the path.  900 will climb over short hills, but you must aim over the hill.  Also make sure each end has as much clear space before hitting trees.  Aiming right at a tree is not going to work well. 

ubiquiti certified trainer :: ubwa | uewa
New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

[ Edited ]

Claude,

Thank you. We are about a city block on each side before we hit any trees at all. No hills in the way. I am confused as to how the radio wave travels from the dish. Is it a flat wave as in Figure B or is it in Figure A?

I always thought radio waves traveled like Figure A.

m900.jpg
SuperUser
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Registered: ‎02-03-2013
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Re: Beam spread Question

The signal travels in a fresnel.  900 has a fairly large one.  Think of a football (american) with each tip being a side of the link.

 

If there are no hills, and trees only a block away, you have a serious aiming problem. 

 

Can you show the wireless tab on the radios?

ubiquiti certified trainer :: ubwa | uewa
New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

 
wire.jpg
SuperUser
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Re: Beam spread Question

On the access point side, can you click Stations at the bottom?

 

I still think either the trees are extremely dense, or there's a serious aiming issue going on here. 

ubiquiti certified trainer :: ubwa | uewa
New Member
Posts: 11
Registered: ‎07-14-2017

Re: Beam spread Question

Claude, I am not able to connect to the access side at this time. I will have to drive out there. Could part of my problem be that the Station antenna is 20' above the height of the Accespoint?

Ubiquiti Employee
Posts: 47
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Re: Beam spread Question

The devices need to be pointed directly at each other. If the station is higher than the access point then you need to point the station slightly down. The AP needs to be pointed slightly up. They should be pointing at each other vertically and horizontally.
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