Which Omni Antena Model needed for AIR-LAP1252G-E-K9 ?

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Jan 25th, 2010
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Dear Sir,


I want to use AIR-LAP1252G-E-K9 (only 2.4 Ghz and no 5 Ghz or  single band)


(with wireless controllers offcourse ) in some hotel with many floors.I cant fix the A.P in rooms but

outside the room i.e on corridor ceiling or may be antena can be mounted on walls of corrdor too



Plz suggest all omni antenae from 3 DBi to 6 Dbi range which can be connected/supported on

AIR-LAP1252G-E-K9



I think (may be I am wrong) if I use higher DBi (4 to 6 DBi) then signal can raech farther (through many concrete walls)

as compared to 3 dBi dipole or integated antena used in cisco 1140 series A.P ?



Please note that the situatiuon is such that imagine we have a flat with many rooms and many conceret

walls......and we can only fix the A.P outside the flat main door but not inside the flat rooms.So our requirement is

that we want signal coverage inside all the rooms of the flat/suite by keeping the A.P outside the flat main door


is it correct to say that one conceret wall will reduce the coverage by at least 15 meters?

so if two walls then 15+15=30 m reduction? and so on?


Thank you all in advance.


abdul

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gamccall Tue, 01/26/2010 - 06:12
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If you're using the 1250 it must be to support 802.11n, in which case you must use either a 3-element antenna such as the AIR-ANT2430V-R, or 3 identical single-element antennas (dipoles, or non-diversity external antennas). You may not use a diversity (two-element) antenna for 802.11n.


The complete list of antennas is here: http://www.cisco.com/en/US/prod/collateral/wireless/ps7183/ps469/product_data_sheet09186a008008883b.html


Don't think of gain as power. Think of gain as shape. Imagine that your coverage pattern is a balloon: your antenna does not change the volume of the balloon, it only changes the shape of the balloon. A low-gain antenna has a nearly spherical coverage pattern. As gain increases, the balloon gets distorted in one way or another: a high-gain omni antenna is a balloon that's squished at the top and bottom, so you gain horizontal distance but lose vertical distance. A patch antenna is squished into a cone, so you gain distance in one quadrant while losing distance everywhere else. A yagi is a balloon squished into an even narrower cone.


In deployments with lots of walls, it's almost useless to think in terms of distance. Think in terms of number of walls instead. In some environments, your signal will penetrate 3 walls but not a fourth. With more solid construction, you may only get 2 walls, or even just 1. The only way to know for sure what your penetration is going to be like is to do a survey with your actual equipment.


Finally, the 1250s are huge, ugly, expensive, and require proprietary POE. I'd recommend using the 1140 for absolutely any situation where it's possible to do so.

Leo Laohoo Tue, 01/26/2010 - 13:35
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Good news and bad news.


First, the good news.  Cisco recently released a new batch of antennaes specifically for the 1250 series AP.  The bad news is that information regarding all of them have not been fully updated yet.  The AIR-ANT2451NV is a "dual band MIMO low profile ceilng mount antenna.  The antenna operates in the 2.4- and 5-GHz frequency ranges and is designed for indoor use."


Cisco Aironet Dual Band MIMO Low Profile Ceiling Mount Antenna (AIR-ANT2451NV-R)
http://www.cisco.com/en/US/prod/collateral/wireless/ps7183/ps469/data_sheet_ant2451nv.pdf


The 1250 is not designed to be deployed in an office-related environment.  It's more ideal to deploy the 1250 in a warehouse, theatre or hanger environment.  For an office or hotel location, reconsider the 1140.


Q & A:  Cisco Aironet 1140 Series and 1250 Series Access Point
http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps6973/ps8382/prod_qas0900aecd806b7c82_ps10092_Products_Q_and_A_Item.html


Data Sheet:  Cisco Aironet 1140 Series Access Point
http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps10092/datasheet_c78-502793.html

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