Noise-floor information

Brad · March 1, 2006, 6:50am

Can someone (possibly from MT) please explain how the noise-floor information is calculated? I can run a snoop or freq-usage and find the absolute worst channel to operate on, setup my wlan on it and MT shows a -98 noise-floor and then change to a clear channel (low bandwidth usage) and it shows a -92.

Is anyone else having any luck using these values to determine clear channels? It would be nice to see some documentation on determining the best channel to operate on. There are so many tools now with the Scan, Freq. Usage, snooper, etc but no documentation to back them up.

Equis · March 24, 2006, 10:50am

I also was wondering this.

I have noise floor of -107 is that good or bad?

Is -90 better than -107 ? or teh other way around?

Thanks

Beccara · March 24, 2006, 11:12am

From what i know the lower the better, -107 is ALOT better than -90

tully · March 25, 2006, 9:27am

The noise floor is only for non 802.11 activity on the spectrum. 802.11 traffic is not considered noise in this case.

John

taloot · March 25, 2006, 9:54am

me also i have -98 to -99 is that good or bad?
im using AMP 1 watt is that have effect on noise?

ghmorris · March 25, 2006, 5:32pm

John, is Nstreme considered to be 802.11 for purposes of calculating the noise floor?

Thanks
George

tully · March 26, 2006, 6:39am

Yes, Nstreme uses the same frame encoding (ofdm…) as 802.11.

John

ghmorris · March 26, 2006, 10:54am

Thank you Sir. We are finding this new feature very useful.

George

rastod · March 31, 2006, 4:24pm

how exactly are you finding this new feature very useful?

ericsooter · March 31, 2006, 6:54pm

Because it gives you a clear picture of non-802.11 noise. This could be from propietery wifi stuff, cordless phones, noisy transformers, etc. Not sure if it detects out-of-band harmonics.

Eric

ghmorris · March 31, 2006, 7:42pm

Exactly. Now if we could only have a “spectrum analyzer” type display for noise floor across all the channels life would be truly wonderful.

Check out an Orthogon Gemini for an example of doing it right. Signal strengths and noise floor on a single display across all channels.

George

jp1 · April 4, 2006, 2:37pm

Here is a spectrum analyzer from the Alvarion 900mhz equipment. The display is cumulative, and in this case, it’s been scanning for 6 minutes. It shows average and peak signal levels.