Experience problem with external antenna install to Cisco AP

Unanswered Question
Jul 2nd, 2008


Anybody outhere had experience problem with non-cisco antenna connected to Cisco AP? I had this one external antenna 12 DBi outdoor omni that connected to Cisco AP1242AG - LWAPP. The performance that not really realistic and the signal keep showing intermittent when measure by wireless monitoring tools. Please note that the AP is controlling by WLC and it is configure by select the type of antenna "external" with diversity mode. I did the measurement inside the WLC to be "24 x 0.5 Dbm" equal to 12 DBi for that particular AP.

My question are,

a) Are cisco AP really not capable when connecting to non-cisco antenna?

b) Do i had to change my configuration set up in the WLC.

c) Any missing information that need to be include when connecting to non-Cisco antenna

Please advice

I have this problem too.
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jeromehenry_2 Thu, 07/03/2008 - 03:30


I have successfully used non Cisco antennae with Cisco Aps, although I do not like to do it as predictibility of the signal is not great. So answer to a) is yes, but if you have the choice, prefer a CIsco antenna. It will be known by the controller and performances will be better.

b) your setup is fine... but you have 2 antennas, right ? If you set to diversity, I assume that you have two external antennae, of the same type, in the same area, with the right distance between them, correct? Otherwise, diversity will not work and what you describe is a typical symptom.

c) See b). Just be aware that as WCL doesn't know this antenna spec, it will assume values. When signal dumps, check if the power level was changed on the controller. If not, it might be an issue related to the antenna and not the AP or controller...

Hope it helps


dennischolmes Thu, 07/03/2008 - 08:32

Also bear in mind that antenna performance is only as good as the antenna. Buy from a know good supplier such as gigawave/Tessco. All of their antennae are tested with Cisco controllers.

marzuki123 Fri, 07/04/2008 - 06:52

If the brand are tested that it is worth to try.I will plan to arrange some POC with this type of antenna (gigawave/Tessco).

marzuki123 Fri, 07/04/2008 - 06:46

Hi jeromehenry

Thanks for the remarkable reply. Wish we can work together on this.

Of course for budgetary reason, my customer prefer to bought non cisco AP as their main option

Btw, for b) i had 2 different type of non cisco antenna connected on 1 cisco AP.1 for indoor and another for outdoor. Different type here include different area of coverage.

So this mean that the diversity will not work accordingly. I afraid that WLC is not capable to manage left and right radios for LWAPP AP.

dennischolmes Fri, 07/04/2008 - 08:37

There is only one radio per frequency spectrum in a Cisco AP. Diversity is based on determining which antenna has the best signal and using that one. It then transmits back out on the same antenna it chose to receive. Splitting two different antennae on the connectors, one for inside, and one for outside will technically work but you have not ability to compensate for multipath. This is not an RF design suggestion.

Scott Fella Sat, 07/05/2008 - 09:34

Sparco Technologies also has a vast selection of 3rd party antennas that I have used in the past. They can cross reference any of the Cisco antennas you are looking for.


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