[kismac] Re: Signal strength

  • From: Geoffrey Kruse <gkruse@xxxxxxxxxxxxxx>
  • To: kismac@xxxxxxxxxxxxx
  • Date: Wed, 1 Mar 2006 18:00:56 -0700

On Mar 1, 2006, at 5:51 PM, Geoffrey Kruse wrote:

On Mar 1, 2006, at 5:18 PM, Robin L Darroch wrote:

4.10 ssi_type
The ssi_type field is used to indicate what type of signal strength
information is present: "None", "Normalized RSSI" or "dBm". "None"
indicates that the underlying WLAN device does not supply any signal
strength at all and the ssi_* values are unset. "Normalized RSSI"
values are integers in the range [0-1000] where higher numbers
indicate stronger signal. "dBm" values indicate an actual signal
strength measurement quantity and are usually in the range [-108 - 10].
The following values indicate the three types:

        Value   Description
        0       None
        1       Normalized RSSI
        2       dBm
        3       Raw RSSI

Supposedly, all packets are supposed to contain this header information, so it should be a matter of parsing it and converting it to a standard format.

That looks promising! Any idea what kinds of output various adapters give?

That's just the point, supposedly, the adapter will tell you which of these formats its using.

This is what I get for Airport Extreme Passive mode:

2006-03-01 17:58:16.037 KisMAC[5273] ssi_type = 2

Which means that passive mode is already reporting dbm. However, in the code for ae, we have this:

                f->silence = af->ssi_signal + 155;
                f->signal = af->ssi_noise;

Who knows what this is for?


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