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Posted by:dragorn
Subject:Reducing detection or filtering on signal strength. RPI3 (Nexmon)
Date:01:45:40 14/06/2018

> I'm using Raspberry Pi to try to get a ballpark of mobile devices present in a zone.
> I want to reduce the dataset either by reducing radio sensitivity and therefore a lesser area or simply filter out that data.
> Should this be done at driver level (Nexmon on raspberry pi) or does Kismet have some kind of control of this?

Unfortunately most wifi cards have a fairly limited dynamic range on their signal reporting; typically only a few db between visible and not. Since the nexmon stuff is a bit of a hack on top of things, i'm not sure if it's got viable signal level reporting at all, unfortunately.

The "proper" way to do it would be to add attenuators to reduce the effectiveness of the antenna, but there are no external antenna jacks on the rpi that I'm aware of.

You can see the signal levels as a second/minute/hour average in the RRD fields of the seenby records for each datasource which has seen a device, so you could use that to only consider datasources which have seen it with a threshold signal level and see if that gets you closer to what you're trying to capture.

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