Configuring 2702i Survey AP power settings

[dablakester]

When configuring the transmit power level for a 2702i, does the transmit power level on the CLI already take into account the internal antenna gain or should you take into account this when selecting thelevel? 

i.e. If I want to transmit 2.4GHz at 25mW, should I set the power local to 10 dBm (10 mW) plus the 4dBi gain so as to make 14dBm?

Thanks

[Scott Fella]

This is the radio TX power. This power doesn't change even when you change the antenna to a different gain. This is also how the controller sets up tx power also.  So if you use internal antennas and the some with various external, then your coverage would vary even when using the same to power due to the EIRP.

hope this helps

-Scott

[dablakester]

Hi Scott,

So, for 25mW EIRP, I would use radio transmit power of 10dBm on the CLI and then let the 2702i internal antenna gain of 4dBi make that up to 14dBm.?

Do I need to configure the antenna gain of 4dBi in the CLI or is that done automatically?

[Scott Fella]

You don't need to specify the antenna gain.  As far as the EIRP, do exactly what you are doing as long as your not going to be mixing antenna gain. 

-Scott

[dablakester]

Hi,

Thanks for that. Mixing antenna again as in 2.4 and 5?

[Scott Fella]

No, mixing in the environment using different gain antennas. 2.4ghz and 5ghz have separate tx power so that doesn't matter. 

-Scott

[dablakester]

thank you!

One more quick question: What is the antenna gain config command on the CLI used for?

[Scott Fella · Accepted solution]

That command is used for reference only.  You can take a look at the config guide for more detail. 

Specifies the resultant gain of the antenna attached to the device. Enter a value from –128 to 128 dB.
Note This setting does not affect the behavior of the wireless device; it only informs the management platform on your network of the device antenna gain.

Hope this helps.

-Scott

[dablakester]

It has, thanks again !

[dablakester]

Hi. The antenna gain command on the radio interfaces is causing a lot of confusion. Some people are saying it adds actual gain to the antennas however this contradicts all Cisco documentation which, as you've said, doesn't affect the wireless device. Is there anymore documentation on this?

[Scott Fella]

Hope this will help:

Command
Purpose
Step 1

configure terminal

Enter global configuration mode.
Step 2

interface dot11radio {0 | 1 slot / port }

Enter interface configuration mode for the radio interface. The 2.4-GHz radio is radio 0, and the 5-GHz radio is radio 1.
The 802.11n 2.4-GHz radio is radio 0
The 802.11n 5-GHz radio is radio 1.
Step 3

antenna again dB

Specifies the resultant gain of the antenna attached to the device. Enter a value from –128 to 128 dB.
Note This setting does not affect the behavior of the wireless device; it only informs the management platform on your network of the device antenna gain.

http://www.cisco.com/c/en/us/td/docs/wireless/access_point/15-3-3/configuration/guide/cg15-3-3/cg15-3-3-chap6-radio.html

-Scott

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