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HP 425 Radiation Pattern

 
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Aarón
Frequent Advisor

HP 425 Radiation Pattern

Hello everyone,

 

we just bought a couple HP 425 APs and I was wondering if the radiation pattern is the same as the MSM430. I found that it is not totally spherical here:

 

https://www.google.es/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CC8QFjAA&url=https%3A%2F%2Fh20565.www2.hp.com%2Fportal%2Fsite%2Fhpsc%2Ftemplate.BINARYPORTLET%2Fpublic%2Fkb%2FdocDisplay%2Fresource.process%2F%3Fjavax.portlet.begCacheTok%3Dcom.vignette.cachetoken%26javax.portlet.endCacheTok%3Dcom.vignette.cachetoken%26javax.portlet.rid_ba847bafb2a2d782fcbb0710b053ce01%3DdocDisplayR...

 

The horizontal plane is quite spherical, but the vertical one has a front and back lobe, being the back the lowest emission part. What I don't know is how to place the AP in the vertical plane, what side of the AP is the front lobe??? Knowing this we can place the AP accordingly in the installations so the back lobe points to the ceiling.

 

 

Any help would be much appreciated!

 

Aarón

 

 

 

2 REPLIES 2
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Manfred M.
Advisor

Re: HP 425 Radiation Pattern

Hi Aarón!

 

I'm also concerned about the fact, that there is no clear advice in the installation manuals about the mounting.

I think that all ap's with internal antennas have almost the same radiation patterns.

 

When you look at the radiation patterns, you should mount the 425 in most of the cases (especially at 5GHz) on the ceiling. (only on staircases or for hotspots in conference rooms wallmount maybe better)

 

Only with ceiling mount you will have a constant 360 degree radiation and the "bad" directional lobe spikes will point upwardly (The asymetric lobes on the back will be not so important as they are pointing into the ceiling)

 

Radiation pattern usually shows azimut and elevation - horizontal and vertical is also not totally clear.

Usually azimut is horizontal.

 

When the ap is positioned on a table you will have an almost constant signal when you walk around the table, but only 180 degress above the table (the -3db beamwidth point -which is the definition for the aperture angle- in the vertical radiation pattern of 5GHz it is far below 180°; at 2,4Ghz its slightly less than 180°).

 

But again - you are right:

Without knowing the position of the ap in relation to the printed patterns they are almost useless.

And - it would be interesting, where exactely the worst point on the vertical pattern on the 2.4GHz Band is.

 

Another big vendor is much more accurate in giving advices for the mounting of ap's in almost all possible situations (even with colour pictures of example locations) - and he suggests the mounting on the ceiling.

 

It would be so easy to place a picture of the AP beside the radiation pattern diagrams or even inside the diagrams for clarification.

 

Hope you found an answer already - I will try to measure it with my AirMagnet tool next time I receive a 425.

 

Manfred

 

Highlighted
Aarón
Frequent Advisor

Re: HP 425 Radiation Pattern

Hello Manfred,

 

my and my colleagues discussed about this and we came to a conclusion. As you can see in the vertial radiation pattern there is a higher loss in the lower right side, we believe that it is because of the APs RJ45 connectors,  so the AP is placed in that graph vertically with its connectors to the downside.

 

I haven't tried to measure it makes kind of sense. Thank you for answering my post!

 

 

Cheers,

 

Aarón