Cisco 1252 with six omnidirectional antennas

[ArmandoGUrrutia]

Does anyone knows how to setup a Cisco 1252 (or similar) with six omnidirectional antennas?

I want to install three 15dBi antennas for the 2.4GHz radio and three 10dBi for the 5GHz.

Is this configuration ok? It's not too much for the ap?

Thanks in advance.

Armando.

[Leo Laohoo]

What are you trying to do?  Those antenna have WAAAAAY TOO MUCH power in order to provide wifi access.

[ArmandoGUrrutia]

I wanna provide wifi access to students and teachers inside a university campus.

These antennas are going to be at the top a of building and the main goal is to

provide signal on open areas. I was doing a little research about the coverage

(20m, 50m, etc) of a 15dBi antenna but I haven't found anything yet.

For 70-100m, do you think one antenna could do the job?

[Leo Laohoo]

For 70-100m, do you think one antenna could do the job?

Maybe.  The clients maybe able to hear the signal from the antenna but the antenna won't be able to hear the signals coming back from the clients.

Look at the horizontal and vertical azimuth planes.  Chances are you are using a point-to-point antenna and the signals "footprint" is shaped like a knife.

On top of the roof???  How high is this roof?  Draw us a picture of the layout of the buildings and the area of the coverage you intend. 

[George Stefanick]

Another item i want to raise ... WiFi is a CSMA-CD medium. It uses 2 senses. Virtual and Phyiscal. So think of a HUB, thats how an access point talks over wireless

The large your area of coverage the more folks will have to share (fight) for medium.

FYI

[George Stefanick]

Little RF math

Every 3 dBi gain in antenna you double TX power. Example:

100mw (AP) + 15 dBi gain antenna =

100+3 (200mw)+3 (400mw) +3 (800mw) +3 (1600mw) +3 (2400mw)

Your wireless clients on most laptops talk at 45mW and if you added an AP at 100mW and added a 15 dBi gain antenna you would have a LARGE link budget problem. Your access points would be yelling at your clients but as you gain distance between you can the ap the client will not be able to talk back.

Does this make sense?

Client 45 mW -- Ap 2400mW

My advice -- 3 dBi on 2.4 and 4 -5 dBi on 5 ghz ..

if you find this post helpful please support the rating system.

[Leo Laohoo]

George got a new RED star!

[George Stefanick]

i did ... i did ...

LOL

[Alan Daniel Chavira Rodriguez]

Hello Everyone,

I have one client with Cisco AP1252 and One AIR-ANT24120 (12 dBi Mast Mount Omnidirectional), Diversity OFF, only receive and transmit on one port ont the 2.4 radio.

So, my client have very good signal but very high latency around 80ms.

Can I do some config to improve this AP with the same Hardware or recommend change the antenna and put others?

Best Regards

[Leo Laohoo]

So, my client have very good signal but very high latency around 80ms.

When dealing with wireless always remember that it's a two-way-street.  Ok, so you have a very powerful 12 dbi antanna shooting the signal downrange.  Sure the client can hear the signal (loud-and-clear) but the question you should ask is this, does the client's Wi-Fi antenna have a similar power to shoot the signal back to the WAP?  Unfortunately, the answer is no.

So this is the reason why the client can see (or hear) a very good signal but the WAP can't.  This is because the client does not have enough transmission strength to shoot the response back to the WAP.

[Alan Daniel Chavira Rodriguez]

Great Explanation Leolaohoo

Best Regards

[Scott Fella]

Like the other post mentioned... Too much power... Your client might be able to see the signal from the AP, but the signal from the client back to the AP is probably poor and that is why you have the latency. You better off with a mimo antenna of 2-5 dbi

Sent from Cisco Technical Support iPhone App

[Alan Daniel Chavira Rodriguez]

Hello Scott,

I was looking the AIR-ANT2506 (5.2dbi) and the AIR-ANT5160V-R (6dbi)  for external use.

What do you think?

Best Regards

[Scott Fella]

You are better off with those. How is your setup anyways? Indoor or outdoor? Open space?

Thanks,

Scott Fella

Sent from my iPhone

[Alan Daniel Chavira Rodriguez]

Outdoor with Open Space.

Best Regards