Cisco Access point 2802i Tx Power Chart

Most of the common issue that we are experiencing during the wireless optimization process is to find the optimal Tx power that will be configured on all Access Points.

As of today, we have many models of the Cisco Wireless Access Points but all of them have different Tx Power and Antenna gain parameters.

In all technical aspects, we could find the maximum supported Tx power (power level) but we don’t have any information about the maximum Tx power that is supported per channel.

As an example:

On 5Ghz UNII-1 channels, the maximum supported Tx power is 16dBm but on UNII-3 channels we could support up to 23dBm.

Configured Tx Power vs Real Tx Power (EIRP)

On our controllers, we can configure Maximum/Minimum Tx power that could be used by Access Points.

Configured Tx power applied only on the Access Point transmitter (without taking into the consideration antenna gain).

Cisco 2802i Antenna Specification

https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-2800-series-access-points/datasheet-c78-736497.html

EIRP (Effective Isotropic Radiated Power)

EIRP is the actual amount of signal leaving the antenna and is a value measured in db and is based on 3 values:

a) Transmit Power (dBm)

b) Cable Loss (dB)

c) Antenna Gain (dBi)

To determine EIRP follow this equation:

<Transmit Power> – Cable Loss + Antenna Gain = EIRP

For example we have a Cisco access points running at full power with a 6dBi antenna on the 802.11a radio and a 2.5dBi antenna on the 802.11b/g radio.

802.11a EIRP = 17dBm (40mw) – 0dB + 6dBi = 23dBm = 200mw of actual output power

802.11bg EIRP = 20dBm (100mw) – 0dB + 2.5dBi = 22.5dBm = 150mw (approx) of actual output power

https://community.cisco.com/t5/wireless-mobility-documents/snr-rssi-eirp-and-free-space-path-loss/ta-p/3128478#toc-hId-1040688787

Tx Power Chart

CLI:

show advanced 802.11-abgn summary

show advanced 802.11a txpower

Channels Max Tx power dB Allowed Power Levels 1-8
2.4Ghz 1 23 23/20/17/14/11/8/5/2
2 23 23/20/17/14/11/8/5/2
3 23 23/20/17/14/11/8/5/2
4 23 23/20/17/14/11/8/5/2
5 23 23/20/17/14/11/8/5/2
6 23 23/20/17/14/11/8/5/2
7 23 23/20/17/14/11/8/5/2
8 23 23/20/17/14/11/8/5/2
9 23 23/20/17/14/11/8/5/2
10 23 23/20/17/14/11/8/5/2
11 23 23/20/17/14/11/8/5/2
Channels Max Tx power dB Allowed Power Levels 1-8
UNII-1 36 16 16/13/10/7/4/2/0/0
40 16 16/13/10/7/4/2/0/0
44 16 16/13/10/7/4/2/0/0
48 16 16/13/10/7/4/2/0/0
UNII-2 52 17 17/14/11/8/5/2/0/0
56 17 17/14/11/8/5/2/0/0
60 17 17/14/11/8/5/2/0/0
64 17 17/14/11/8/5/2/0/0
UNII-2 ext 100 17 17/14/11/8/5/2/0/0
104 18 18/15/12/9/6/3/2/0
108 18 18/15/12/9/6/3/2/0
112 18 18/15/12/9/6/3/2/0
116 18 18/15/12/9/6/3/2/0
120 NA NA
124 NA NA
128 NA NA
132 18 18/15/12/9/6/3/2/0
136 18 18/15/12/9/6/3/2/0
140 16 16/13/10/7/4/2/2/0
UNII-3 149 19 19/16/13/10/7/4/2/0
153 23 23/20/17/14/11/8/5/2
157 23 23/20/17/14/11/8/5/2
161 23 23/20/17/14/11/8/5/2
165 23 23/20/17/14/11/8/5/2

Available channels:

Not all the countries will support all the channels on both bands.

Please check your Regulatory Domain in link below:

https://www.cisco.com/c/dam/assets/prod/wireless/wireless-compliance-tool/index.html

Note:

The table above has been created based on Regulatory Domain A (Canada).

Reference:

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_cisco_aironet_series_2800_3800_access_point_deployment_guide/b_cisco_aironet_series_2800_3800_access_point_deployment_guide_chapter_01.html

https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-2800-series-access-points/datasheet-c78-736497.html

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