tx-power questions

e-chuah · ‎10-11-2009

Hi,

attached is the output of

"show country supported tx-power" command in WLC6.0.

From there you can see the max tx-power for each country. From the output, u can see that most of the tx power is 20dBm for b/g. However, in the CCO doc "channels and maximum power settings for LighWeight AP" document, it shows 17 for most of the countries.

WHy is there a difference? Am i missing anything?

Thanks

Eng Wee

jeromehenry_2 · ‎10-12-2009

Which cco document are you referring to?

Local regulations usually imply both max transmit power at the AP level, and EIRP (Effective Isotropic Radiated Power). EIRP combines AP transmit power, (cable loss) and antenna gain, and this gives you the max power allowed at your AP antenna level. So depending on if the AP has an external antenna or not, the AP max transmit power may vary to take the AP antenna gain into account...

So make sure that you read a document that matches the AP type...

hope it helps

Jerome

e-chuah · ‎10-17-2009

Hi jerome,

i was referring to

http://www.cisco.com/en/US/docs/wireless/access_point/channels/lwapp/reference/guide/lw_chp2.html

I have attached a portion of the doc. The

output of "show country supported tx-power" is higher.

Am i missing anything ?

Thanks

Eng Wee

palthainon · ‎10-13-2009

Yes, different countries have different power level limits. The FCC regulates the US's and our max DBM is 36 (30dbm power with 6dmb gain). You can adjust the power as long as you adjust the gain in a 3:1 ratio. Other countries go by a 1:1 ratio.