BR1310G in ap mode coverage issue

Unanswered Question
Sep 28th, 2010
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I have a single AIR-BR1310G-A-K9 with external antenna AIR-ANT2506 in access point mode that I am having a very difficult time getting solid coverage.

It's in a new install with the ap mounted on an external wall with the mast antenna.  I only have two wireless clients that need connectivity, both are IP cameras. They are both about 250 to 300 ft. from the ap with clear line of site, across an open parking lot.  One is directly to the south and the other is directly to the west.

The problem I'm having is that the mast antenna seems to be extremely sensitive in it's veritical alignment.   If I mount the antenna perfectly veritical the south client connects fine but the west client gets a somewhat bad connection.  If I tilt the mast antenna slightly to the west so that it's horizontal plane points directly at the west antenna then the results are exactly oppisite, the west client is strong and south client is weak.

The west client physically sites about 10 -15 feet lower than the ap, and the south antenna is the same height as the ap.


By looking at the antenna's spec's and E-Plane and H-Plane that I wouldn't have had a problem at those distances.


Part of the problem may be that the clients are wireless camera's and i'm trying to stream video over the connection.  When it's good, the video is great, when it's bad the video is pretty choppy.  The quality depends on exactly how I have the mast antenna tilted (it's a VERY slight tilt)


So my question is whether this sounds normal.  Should I expect this type of coverage?  What's the best way to fix this? Can I add a second antenna which points directly at the other client?

Is there something wrong or missing from my config?  ( I noticed an external antenna gain setting in the setup which is disabled by default)

Thanks for any suggestions.

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Overall Rating: 5 (3 ratings)
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Serge Yasmine Wed, 10/06/2010 - 06:33
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  • Cisco Employee,

Hi Chris,


Can you get "show run int do 0" form the Access Point please?


- Have you specified antenna receive and transmit to be inline with the connected antenna slot under the radio interface?

- Channel in use?

- Is the video transmission over multicast or unicast?

- How high is the Antenna placed above the ground? Did you do the calculation and have correct elevation from the ground to cover the required range?-


Thx

Serge

chris fricke Wed, 10/06/2010 - 09:10
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Thanks for the reply,


Here is show run int do 0:

#####################################


ap#show run int do 0
Building configuration...

Current configuration : 410 bytes
!
interface Dot11Radio0
no ip address
no ip route-cache
!
ssid MADDOX
!
speed basic-11.0 24.0 36.0 48.0 54.0
channel 2462
station-role root access-point
cca 75
concatenation
infrastructure-client
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
bridge-group 1 spanning-disabled
end

#############################################


ap#




""Have you specified antenna receive and transmit to be inline with the connected antenna slot under the radio interface?""

-I'm not sure what you mean by this,  I have changed any settings related to the antenna.  The only antenna settings I see in the config utility are as follows:

Receive Antenna:  Diversity (selected)      Left-secondary(unselected)      Right -primary(unselected)

Transmit Antenna:  Diversity (selected)     Left-secondary(unselected)      Right  primary(unselected)

External Antenna Configuration:  Disabled

  Antenna Gain: Disabled



-The video transmission is Unicast


-The antenna is about 20' above ground. I tried moving it up to about 25' to 30' but it made no difference.  I I'm not sure what calculation to do to determine if my elevation is enough.


Thank you for the help.

Serge Yasmine Thu, 10/07/2010 - 02:26
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  • Cisco Employee,

Hi,


Since you are using 1 external antennna adapt the configuration under the radio interface (depending on which slot you used)


antenna receive right|left

antenna transmit right|left


Diversity is used when two antennas are plugged.


With regards to distance and elevation, have a look at: http://www.cisco.com/en/US/products/ps5861/index.html


Click on


Outdoor Bridge Range Calculation Utility
Estimate the range that can be expected, using factors such as antenna gain, transmit power, and path-loss exponent


This is a good calculation tool.


Also I would enable 5.5, 6 and 9 Mbps under the radio interface and leave 1 and 2 as disabled, just to be on the safe side vis-a-vis signal strength and data rates.


Regards
Serge

chris fricke Thu, 10/07/2010 - 08:43
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I'm going to give that a try.


Is it necessary to manually input the external antenna gain?

I would have to "enable" external antenna configuration and type in the gain number, which is 5.2 in my case.

Currently that external antenna configuration option is set to disabled.


Thanks,

Chris

Serge Yasmine Thu, 10/07/2010 - 10:03
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  • Cisco Employee,

Hi Chris, Yes please and let me know how it goes, if still not working well.

Thanks
Serge

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