The problems being discussed here are inherent to any fixed (internal)
omni antennas. If you look at the typical radiation pattern for most
omnidirectional antennas it will not look like a perfect sphere, but
rather like a donut. Imagine taking an underinflated ball and pushing in
from the top and bottom. Past AP's with external rubber ducks allow the
antennas to be angled 90 degrees to compensate for horizontal or
vertical mounting. The majority of AP's being designed these days with
internal antennas are optimized for mounting on a ceiling grid.
Rick
Richard E. (Rick) Brown
Network Systems Engineer
Communication Technologies
Office of Information Technology
N.C. State University
(919) 515-5489 office
(919) 515-1641 fax
(919) 601-1651 cell
[email protected]
http://www.ahecta.org/
Lee H Badman wrote:
Much of this is recent- and disturbing in that Cisco seems to have
“snuck it in” at some point in the recent past. The “avoid vertical
surfaces” for mounting is 100% contrary to original 1130 documentation
where they went so far as to show the different patterns to leverage
between wall and ceiling mount in the data sheet, playing up the
options and flexibility provided by having your choice of either
orientation.
We did site surveys- but still have many, many 1130s that are
vertically mounted for lack of any other option, or for aesthetics. I
will be asking our SE to get an explanation from the WBU on why it was
OK to mount 1130s vertically, and now there is some unexplained taboo
to it.
-Lee
Lee H. Badman
Wireless/Network Engineer
Information Technology and Services
Syracuse University
315 443-3003
------------------------------------------------------------------------
*From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
[mailto:[email protected]] *On Behalf Of *Kellogg,
Brian D.
*Sent:* Wednesday, May 13, 2009 4:02 PM
*To:* [email protected]
*Subject:* Re: [WIRELESS-LAN] Cisco 1131ABG AP
*The below was taken from Cisco’s installation instructions for
the 1130AG APs. Note the last bullet point. I don’t remember ever
reading that in 2007 when we purchased and installed them. It
seems to be a late addition as evidenced by the discussion thread
sent in the first email on this subject. My institution declined
paying for a site survey before installation so I can’t completely
or even primarily blame Cisco. A site survey is always wise, but
this would still have been nice to know then.*
*http://www.cisco.com/en/US/docs/wireless/access_point/1130/installation/guide/113h_c2.html#wp1082741*
* *
*Basic Installation Guidelines *
Because the access point is a radio device, it is susceptible to
interference that can reduce throughput and range. Follow these basic
guidelines to ensure the best possible performance:
· Ensure a site survey has been performed to determine the optimum
placement of access points.
· For lightweight access points, check the latest release notes to
ensure that your controller software version supports the access
points to be installed. You can find the controller release notes by
selecting your controller under *Wireless LAN Controllers* at this
URL:
http://www.cisco.com/en/US/products/hw/wireless/tsd_products_support_category_home.html
· Ensure that access points are not mounted closer than 20 cm (7.9 in)
from the body of all persons.
· Do not mount the access point within 3 feet of metal obstructions.
· Install the access point away from microwave ovens. Microwave ovens
operate on the same frequency as the access point and can cause signal
interference.
· Do not mount the access point outside of buildings.
· Do not mount the access points on walls or other vertical surfaces.
Thank you,
Brian Kellogg
Network Services Manager
St. Bonaventure University
716-375-4092
*From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
[mailto:[email protected]] *On Behalf Of *Lee H Badman
*Sent:* Wednesday, May 13, 2009 10:21 AM
*To:* [email protected]
*Subject:* Re: Cisco 1131ABG AP
Weird. Here is this statement from document C78-401677-01 07/07:
*Applications*
In offices and similarly open environments, Cisco Aironet 1130G Series
Access Points can be installed on the ceiling to provide users with
continuous coverage as they roam throughout a facility. In school
buildings and similar facilities, the access points can be installed
on the ceiling of each room and hallway to provide users with full
coverage and high network availability. *In areas where a ceiling
installation may not be practical, such as retail hotspots or similar
small facilities, the access points can be mounted simply and securely
on walls for complete coverage with minimal installation cost.*
Also- I was very surprised to see that the current data sheet does not
show the ceiling-mount versus wall-mount antenna patterns anymore. It
certainly used to, and basically the change between wall/ceiling isn’t
that drastic- just a change in vertical/horizontal beamwidths and
subsequent influence on antenna pattern- but when close to the AP,
there should be no performance difference noted (we have plenty of
both). See if this picture comes through- screenshot from original
13-page 1130 data sheet. If you need the whole doc, email me directly.
Lee H. Badman
Wireless/Network Engineer
Information Technology and Services
Syracuse University
315 443-3003
------------------------------------------------------------------------
*From:* The EDUCAUSE Wireless Issues Constituent Group Listserv
[mailto:[email protected]] *On Behalf Of *Kellogg,
Brian D.
*Sent:* Wednesday, May 13, 2009 9:39 AM
*To:* [email protected]
*Subject:* [WIRELESS-LAN] Cisco 1131ABG AP
It seems the 1131 AP from Cisco performs best when mounted on a
horizontal surface; see below. We’ve been trying to discover why some
areas have weak signal strength despite close AP placement. We’ll be
investigating this this summer by reorienting some APs to the
horizontal and see if that helps. Unfortunately due to building
construction here it is very difficult to get some APs in a horizontal
orientation when taking aesthetics into consideration. Anyone else run
into this issue?
http://www.cwnp.com/phpBB2/viewtopic.php?p=16189
Thank you,
Brian Kellogg
Network Services Manager
St. Bonaventure University
716-375-4092
********** Participation and subscription information for this
EDUCAUSE Constituent Group discussion list can be found at
http://www.educause.edu/groups/.
********** Participation and subscription information for this
EDUCAUSE Constituent Group discussion list can be found at
http://www.educause.edu/groups/.
********** Participation and subscription information for this
EDUCAUSE Constituent Group discussion list can be found at
http://www.educause.edu/groups/.
********** Participation and subscription information for this
EDUCAUSE Constituent Group discussion list can be found at
http://www.educause.edu/groups/.
--
Richard E. (Rick) Brown
Network Systems Engineer
Communication Technologies
Office of Information Technology
N.C. State University
(919) 515-5489 office
(919) 515-1641 fax
(919) 601-1651 cell
[email protected]
http://www.ahecta.org/
**********
Participation and subscription information for this EDUCAUSE Constituent Group
discussion list can be found at http://www.educause.edu/groups/.
