I haven't used it, so I'll guess at your answer:
Any laptop based survey tool depends on the "RSSI" data provided by the wifi adapter it's using.
If you buy ESS, it should come with an "Ekahau NIC-300 Wi-Fi Adapter" but it's compatible with others.
There's no standard for calibrating RSSI from a wifi card and wifi cards can put out very different numbers from each other.
If the site survey tool isn't configured to know exactly what the RSSI values from a certain card mean and how to map that to dbm (decibel differences from a milliwatt) values, then all bets are off.
No, I'm talking about what power level must I set on a particular Ruckus AP when I want to perform a predictive site survey. I need to input the right power output for the virtual AP. The default value is 25mW for both bands which is wrong probably
Ah. I think you need EIRP values.
This is different per AP.
That information can most easily be found on the Ruckus Product Guides, conveniently hidden away here:
Maybe Keith could find us a better link to this on the Ruckus site somewhere.
(I wasn't able to find it)
Unfortunately, you seem to need this in mW and the product guide presents it in dbm.
So... take each dbm value and... um...
mW is 10 to the power of (dbm/10)
So... a 7982's 2.4Ghz power is 34dbm which is 10 to the 3.4 which is...
Hmm.. That sounds high (slightly higher than a class-1 cell-phone) certainly very powerful for a wifi device.
The same math gives me 1584mW for the 5Ghz band.
What that RW table of APs is showing is MAX EIRP, not what is allowed in a specific country.
There's a much easier way of calculating how much a certain dBm is in mW actually. For example take those 34dBm. You get to that by subtracting 2 times 3dB from 40dBm rigt. So 40dB - 3dB - 3dB. 40dB is 10.000 (count the zeros). So 40dBm is 10.000mW or 10W. Each 3dB less devides that by factor of 2.
So the first 3dB means 5000mW and the second 2500mW or 2,5W and there you go.