Wireless Access

Occasional Contributor II

rf math


How is that possible 


25mW =eirp(17dBm)




Guru Elite

Re: rf math

Please show us the whole screenshot so you know what you are talking about.

Colin Joseph
Aruba Customer Engineering

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Occasional Contributor II

Re: rf math


Sorry for that , i forget to post the gain part

Thank you 



Re: rf math

EIRP = Transmit power - Losses + Gains



From your screenshot: 14mW Transmit power, 0 dB loss, 5 dB antenna gain.


1 mW = 0 dBm by definition

2 mW = 3 dBm

4 mW = 6 dBm

8 mW = 9 dBm

16 mW = 12 dBm


And 12 dBm (which is the 16 mW transmit power) - 0 dB (cable loss) + 5 dB (antenna gain) = 17 dBm EIRP.


So the EIRP depends on the antenna gain, which makes it possible in your first screenshot that the same transmit power results into different EIRP values.

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