You'll also notice in that output on the blog that for 802.11a data rates, power level 1 is actually 14dBm, while 802.11n data rates are at 11dBm . If you look at the Cisco site at http://www.cisco.com/en/US/docs/wireless/access_point/channels/ios/reference /guide/1250_chp.html#wp1194606, it shows the various output levels for both 11a and 11n for each channel. And another PDF for the 3500s/1260s is at http://www.cisco.com/en/US/docs/wireless/access_point/channels/lwapp/referen ce/guide/3500e1260pwr_chn.pdf. It's interesting that the use of 2 transmit antennas bumps up the calculated EIRP 3dB. That would explain the difference between the listed 802.11a and 802.11n data rates in the "show" command. Keep in mind that the 1250 AP (which is what was listed) was tested with antennas up to 6dBi. The total EIRP listed on the www.air802.com site shows that the total for UNI-I is 22bDm. So, with a 16dBm budget, you are left with 14 (which was the stated max under the APs "show" command). Now that there are higher gain antennas certified for use with the 1250s (like the 9.5dBi AIR-ANT5195P-R), you should be careful to put the external antenna gain into the APs configuration in the WLC. The WLC will then adjust the power output for the radio based on the band and antenna gain so that the EIRP stays below 22dBm.
A lot in there, which makes it quite confusing. J Jason Boyers - CCIE #26024 (Wireless) Technical Instructor - IPexpert <mailto:[email protected]> [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Stalder Dominic Sent: Monday, January 03, 2011 7:02 PM To: [email protected] Cc: [email protected] Subject: [CCIE Wireless] TX Power for UNII bands Hi George Happy new year to everybody on the study list! On your blog I found this page: http://www.my80211.com/cisco-wlc-labs/2009/10/30/what-you-need-to-know-about -tx-power-and-80211a-5ghz-on-a-ci.html There you say that the following concerning the power levels (only FCC): UNII-1 max 11dBm UNII-2 and UNII-3 max 17dBm Now I found another page: http://www.air802.com/fcc-rules-and-regulations.html There they say the following (only FCC, see row Point-to-MultiPoint Intentional Radiator Power @ FCC 5 GHz BANDS AND RULES): UNII-1 max 16dBm UNII-2 max 23dBm UNII-2 Extended max 23dBm UNII-3 max 29dBm Im from Europe, so now I am not sure what is correct or if the WLC is not allowing the max values defined by the FCC. It would help me a lot, if you can correct me ;-) Thanks and regards Dominic
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