How to change the direction of the beam of an LAP1252agn?

[Frank Wagner]

Hello,

in our deployment we have mainly the LAP1252agn with both Radio modules installed

and the AIR-ANT5135DW-R 3.5dbi dipole antennas for 5 Ghz and the corresponding 2.2dbi dipole antennas for 2.4 Ghz.

According to the Cisco antennas reference guide one can say, that the elevation plane radiation pattern looks a bit like an eight.

At the moment the antennas on the access points are deployed as seen in figure a) of my attached draft.

My question is, whether it is possible to turn only the antennes in a specific way,

so that the direction of the beam can be changed as seen in figure b).

Or do I have to turn the whole access point as shown in figure c) or to mount it on the ceiling as shown in figure d).

Thanks.

Greetings Frank

[Nicolas Darchis]

Hi Frank,

this is not easy to talk with words. First, since your antennas are articulated, you can achieve any coverage without moving the AP itself.

The coverage patterns seen here :

http://www.cisco.com/en/US/docs/wireless/antenna/installation/guide/5135dw.html

can be identified like this :

Place the ap on a desk. Cisco logo facing upwards (ceiling)

Antennas are straight up (like they would be if they were not articulated). The antennas pointing like fingers to the ceilign.

Then you have the coverage seen on the diagrams of the link I pasted.

H-view is a top view (you are viewing the AP from the ceiling on your desk). You can see it's radiating in all horizontal direcitons.

E-view is a side view (you are sitting on your chair looking at the AP at the same heigh as it) : You can see it's radiating left and right but not so much up and down of the AP.

So this is a "floor" coverage.

If you want a coverage "above and below" the AP then you should articulate the antennas to be parrallel to the AP (pointing the wall then). Direction will nto matter.

I hope it's clear. I'm sorry I'm not using your diagrams as reference as I didn't really understand their significations as it's hard to view this kidn of stuff without 3d view :-)

Nicolas

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[Frank Wagner]

Hello Nicolas,

thanks for your quick response.

Regarding the diagram of your link, one can see, that the beam (mainly look like an lying eight) is mainly radiating left and right.

Is it possible to let the beam radiate from back to front with only changing/turning/artuculating the antennas in another way?

Greetings Frank

[Nicolas Darchis · Accepted solution]

Hi Frank,

You are confusing directions I believe :-)

The shape does an eight from left to right indeed. But this is true, from any side of the AP you are looking at. So you are sitting on your chair, looking at the AP who is at the level of your eyes and you see this 8 shape. Rotate 90 degrees to look at the AP from antoher side : the shape will stay identical.

In 3d, it would be a donut (if you look at it from the side, it radiates left and right but not much up/down).

To take the donut analogy. Imagine a giant donut in your room, this is the coverage pattern (we imagine that there is no hole in the middle of the donut ...). So it radiates horizontally on the whole floor but vertically it barely reaches the floor above and below.

I hope this clarifies. It's really hard to explain to principles without 3d view, and even more since I'm no native english speaker :-)

So to conclude, with the AP on the desk and antennas pointing like fingers to the ceiling, it will radiate left and right but also back and forth.

This is the coverage 99% of the people want.

The only reason you would set the antennas parralel to the AP is if you mount the AP on a wall, then to have floor coverage they would still need to point to ceiling (so 90 deg angle compared to the AP).

Nicolas

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