All, It should be noted that since the 1140 uses standard PoE, it makes some sacrifices in transmit power by data rate and MCS/ Beam-Forming support.
The 1250 just has the standard FCC UNII-band EIRP transmit power restrictions (with Cisco's implicit antenna gain for external antenna connectors), but without transmit power changes by data rate. This may be moot if you survey with an APs at 11dB transmit power anyway. Here's a enlightening dialog I had with Fred Niehaus of Cisco on the NetPro forum, Replied by: bjohns...@partners.org - PARTNERS HEALTHCARE SYSTEMS - Oct 2, 2009, 8:15pm PST Hi Fred, I'm looking at the power levels on the 1140 radios and amazed at the variations in power by data rate. These are in addition to the UNII-band EIRP rules, with some additional antenna gain assumptions on Cisco's part. Are these really FCC-regulated levels? Does MIMO/MRC/ClientLink overcome these limitations to deliver higher sustained legacy rates at range? Active power levels by rate 6.0 to 18.0 , 14 dBm, changed due to regulatory maximum 24.0 to 36.0 , 13 dBm, changed due to regulatory maximum 48.0 to 48.0 , 12 dBm, changed due to regulatory maximum 54.0 to 54.0 , 11 dBm, changed due to regulatory maximum 6.0-bf to 18.0-b, 14 dBm, changed due to regulatory maximum 24.0-b to 36.0-b, 13 dBm, changed due to regulatory maximum 48.0-b to 48.0-b, 12 dBm, changed due to regulatory maximum 54.0-b to m6. , 11 dBm, changed due to regulatory maximum m7. to m7. , 10 dBm, changed due to regulatory maximum m8. to m14. , 11 dBm, changed due to regulatory maximum m15. to m15. , 10 dBm, changed due to regulatory maximum m0.-4 to m3.-4 , 14 dBm, changed due to regulatory maximum m4.-4 to m4.-4 , 13 dBm, changed due to regulatory maximum m5.-4 to m5.-4 , 12 dBm, changed due to regulatory maximum m6.-4 to m6.-4 , 11 dBm, changed due to regulatory maximum m7.-4 to m7.-4 , 10 dBm, changed due to regulatory maximum m8.-4 to m11.-4, 14 dBm, changed due to regulatory maximum m12.-4 to m12.-4, 13 dBm, changed due to regulatory maximum m13.-4 to m13.-4, 12 dBm, changed due to regulatory maximum m14.-4 to m14.-4, 11 dBm, changed due to regulatory maximum m15.-4 to m15.-4, 10 dBm, changed due to regulatory maximum Replied by: fredn - CISCO SYSTEMS - Oct 8, 2009, 12:32pm PST Yes this power levels are real (don't be amazed) it's pretty much the same across the board with our competitors as well. What you are seeing here is not an FCC regulated limitation but rather one of PoE. When we design products, such as the 1140 we design to a power of approx 12.5 Watts (yes 802.3af is 15.4 Watts) but the device is designed less as there is loss in Ethernet cable etc. As the data rates go lower the transmitter power goes up since the transmitter EVM limit is relaxed. EVM is the linear or distortion factor, the higher the data rate the less distortion is tolerated. Similar to receiver sensitivity gets better as the data rates go down (since it can decode better through the distortion). If you have a need for higher transmitter power, take a look at the AP-1250 product which can accept a higher PoE rating (beyond that of 802.3af) using our power injector. -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Lee H Badman Sent: Monday, November 09, 2009 2:36 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 1140 Cisco APs If you recall, not too long ago Cisco did come out and say that ceiling mount is strongly recommended- to the point of dropping wall mounting from the text in their documentation. I believe RRM assumes a ceiling mount for whatever it is worth to the enigmatic "algorithm". -Lee -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Procyk, Ian Sent: Monday, November 09, 2009 2:30 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 1140 Cisco APs Kristina, Also be aware of the fact that to mount on a single gang electrical box, you will likely need another adapter plate (or access to a drill press if you want to roll your own). The 1142 brackets no longer have the X-Y holes that the 1131 brackets had, which made the 1131's so nice and easy to mount up against the wall, with only the stuff supplied in the box. We are finding that the current architectural trend on campus, is one that is shying away from t-bar ceilings - hence our need for the alternate brackets. In many cases we are back to open and exposed ceilings with cable tray and pipe. Often an acoustic baffle, made from what can only be described as "pressed wood shavings" is hung from the ceiling as well, these don't like to be drilled or bolted into... Ian Procyk UBC IT 604-827-4707 -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Linchuan Yang Sent: Monday, November 09, 2009 10:31 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 1140 Cisco APs Hi, Kristina We did a test with Cisco 1142 AP. From the results (same location, 12 feet), the coverage of vertical mounting (on the wall) and horizontal mounting (under the ceiling) are almost the same. Please consult with Cisco about the mounting position of 1140 AP; I think both of them are suitable for 1140. Linchuan Yang Wireless Networking Analyst Network Assessment and Integration, IITS-Concordia University Tel: (514)848-2424 ext. 7664 -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Kristina Gasca Kelly Sent: November 9, 2009 1:14 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] 1140 Cisco APs We are a Cisco shop and have begun discussing the deployment of 802.11n APs in our environment. We currently have 22 WiSMs and approx 1100 APs (1240s and 1230s). Currently there are two Cisco flavors of APs the 1252 and 1140. We are shying away for the 1250 series because of the power draw limitation with our current PoE switches. We don't want to start using injectors again or buy all new 3560e switches! However the 1140s were designed to be hung from the ceiling and we only hang wall mounted APs. Has anyone else installed 1140s on the wall, and if so, did you have to change your design methodology? Thanks, Kristina -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Kristina Gasca Kelly Network Operations Manager North Carolina State University Communication Technologies 919.515.0107 (office) 919.515.1641 (fax) krist...@ncstate.net ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ********** 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/. 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