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Community Member

Signal strength decreases on AP in stairwell.

I've got 40 AIR-LAP 1131 APs, in our building. As I approach the 1 in the stairwell with my laptop, my signal strength drops from full bars to barely 1 bar when I get right in front of it(it's mounted on the concrete wall appx 7 feet high). Concrete walls, metal and concrete stairs, but I am directly in front of it. Also, I am using a 4404 Wireless LAN controller for all APs. Do I adjust the power? Any ideas would be greatly appreciated! Thank you!

6 REPLIES
Community Member

Re: Signal strength decreases on AP in stairwell.

It could be that your signal strength is high but that the signal quality is poor because of reflections that cause multi path problems.

Green

Re: Signal strength decreases on AP in stairwell.

It could just be that you're under the signal.

Most Omni antennas have a donut-shaped signal, with the antenna stick being in the center of the hole.

When you start bumping up the gain, the radiation pattern tends to compress, and in some cases, radiate more towards the tip of the antenna (more like a flat cone, with the wide part aimed at the ceiling).

To test this, rotate the AP 90 degrees clockwise (so the antenna would be pointing to the horizontal with you facing the broadside) and see what affect it has on your signal. In this position, the "donut" is now vertical (would look like a car tire) and your system should have much higher signal strength (though not necessarily better signal quality due to the reflective nature of the walls).

Gain does you no good if you don't know the pattern and adjust for it.

Check it out and let us know.

Good Luck

Scott

Community Member

Re: Signal strength decreases on AP in stairwell.

Thanks! I'll let you know.

Silver

Re: Signal strength decreases on AP in stairwell.

Have you checked what power level it is currently set to? It is possible, though unlikely, that the WLC decided that there is enough coverage and could have its power cranked very low.

To confirm the power, on the controller go to wireless->access points->all APs->802.11b/g radios (or a if you are using a) and check what power setting that AP is at.

-Eric

Please remember to rate all helpful posts.

Community Member

Re: Signal strength decreases on AP in stairwell.

Hi,

I have onde doubt.

If i have AP 1200 series with one omni external antenna wiht 12 dB gain, if i configure in ap power local cck 20

and power local ofdm 20 .

And If i want to limit power in my ip phone 7920 clients with power client 20 in AP.

In this sitution this AP EIRP = 20 mw+ 16 mw (of 12db antenna gain)???

AN in 7920 phone client will be 20 mw ??

I don't want to have diferent powers in AP and ip phone because of one way audio.

Thanks,

MC

Green

Re: Signal strength decreases on AP in stairwell.

Antennas are two-way critters; gain works in both directions.

You get the same amplification factor for the inbound signal as well (as long as your client is within the pattern of the antenna)

One-way audio in VoIP is usually a bandwidth problem (i.e., congested channel).

Good Luck

Scott

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