Is it must to use all three antenas in 1250 series for wireless n?

Unanswered Question
Feb 19th, 2010

I want to use Cisco 1250 series devices ( AIR-LAP1252G-E-K9  at 2.4 GHZ ) with wireless

controller of 4400 or 5500 series.
I want to use wall mount patch antenas (I will choose any one of the  following models)

AIR-ANT2460P-R   6 dBi Patch Antenna

or

AIR-ANT2465P-R   Diversity Patch 6.5 dBi

or

AIR-ANT2485P-R   Patch  8.5 dBi

Now my questions are :

01. The 1250 series has options for three antenas connectivity.is it must to use all the three antenas on each LAP ?

02.Suppose I want my Access point to support wireless G and Wireless N ,then can i get it done by using ONLY ONE ANTENA?

03.Suppose I want  my LAP to support only wireless n clients then can I use only one antena on each access point?

04.There are thick concrete walls comming on the way.Which of the above antenas you suggest best?

Thanx in advance.Please answer.

Regrds

Abdul

I have this problem too.
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dancampb Fri, 02/19/2010 - 12:37

You can acheive 'n' rates with two antennas.  Just make sure if you use only two that you connected to the tx/rx ports and not connection C which is rx only.  You will be able to associate at MCS 0-15 but keep in mind that true thoughput will be down without the third antenna.

contact_abdul Fri, 02/19/2010 - 22:06

Thnx to dancampb and leolaohoo

to Mr. Leolaohoo

.....I liked your suggestion to use  latest antenas of cisco.I found that

antena  Ant2460np ( 6 dBi patch with three pigtails or RP-TNC Connectors Output)

because this patch antena seems to have three pigtails and so i dont need to use

three patch antenae per access point  (this will reduce my cost of project).

I dont want to use 1140 series because its antenae are omnidirectional and less than 3 dBI.

and I want the radio signals to pass three tough concrete walls.so i want some directional antena

to focuss its energy/signal in a particular direction instead of 360 Degrees

I want to use 1250 series because i want to use external antena (patch directional)

Its a standard hotel.The walls are thick and also the doors seem to be of wodden but may be inside

fire proof materials are there (both in walls and door).....

there is considerable signal drop if the signal passes through even one wall.

The devices cant be placed inside the flat/suite/rooms. It has to be on the hotel corridor/outside rooms

I am using the patch antena because i want to concentrate the waves in one direction (avoid omni antena)

also i want to use higher dBi Patch antenas (more than 6 dBi till 11 dBi) because I belive (may be i am wrong)

that if i user higher dBi patch antena and higher power transmission settings in the device ( 8 dBi or 11 dBi or 13 dBi)

then i the radio siganls will pass or reach the even the interior rooms of the flat/suite (can pass through THREE WALLS)

Thanx alot to dancampb too.......

Questions too all:

01.Is there higher dBi Patch antena ( 6 dBi to 11 dBi ) with three pig tails tails in one device (latest design for MIMO) ?

02.Please suggest/correct me if I am wrong in my views.My main cocern is not speed but maximum coverage

(even to pass throughtough conditions or three walls )

Leo Laohoo Sat, 02/20/2010 - 00:52

Hi Abdul,

Your issue is not easy nor is your setup the first.  Placing your APs along the hallway makes common sense.  The only suggestion I could provide is to conduct a Wireless LAN Site Survey prior to full deployment.  This is the only way to determine if APs transmission power is adequate or not.  I have a very strong suspicion that the 1140 can do the job well.  (Let me know if I am wrong, please.)

Also consider that if strong enough, the wireless signal can "bleed" or "leak" up one floor.

As to the choice of antennae, I don't remember the exact model, but one of the new antennaes has SIX (6) pigtail/RP-TNC connectors.  This is a single-unit antennae built for both 2.4 and 5.0 Ghz.

Leo Laohoo Fri, 02/19/2010 - 16:10

Hi Abdul,

Late last year, Cisco released a new series of antennaes for the 1240 and/or 1250 APs.  Check the PDF files from here:
http://www.cisco.com/en/US/products/hw/wireless/ps469/products_data_sheets_list.html

I've also noticed that your antennaes that your questions are based on are 2.4Ghz.  I believe you need both 2.4Ghz and 5.0Ghz to get wireless "n" running.

As to thick concrete, no one but you will be able to answer that.  There are many combinations of concrete (including the steel wires).  As far as I know, concrete blocks (or cinder blocks) take approximately -5 to -10 dBm off your signal.  One way to address the issue is not to do with antennae but the placement.

I also agree with Dan, if you want to use full bandwidth of "n" then it's nice if you can get all three antennaes connected.

To make your setup alot simpler, no hassles as to which antennaes to buy, have you considered looking at the 1142 series AP?

Hope this helps.

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