Mark57 wrote:I've been rereading
this thread on a more efficient Kismet channel hopping idea and was wondering/considering in light of that thread what's the best velocity setting to use and why. The default is 5 channels per second. I use 7 with a sourcechannel scheme of 6,6,1,1,11,4,6,11,10,6,1,7,11,6,1,8,6,11,9,6,2,6,6. I've played with the velocity number but have not been able to see much difference in results whereas changing to the custom sourcechannel does make a difference in my area. Just wondering what velocity setting you use and if you have strong feelings about that setting.
I'm using a 1 watt pre amp so I'm usually able to see the signal for a longer period of time and therefore have increased the velocity setting based on that. CPU is 1.7 GHz and card is Senao 2511-CD PLUS EXT2 with a 5.5 dB omni.
PS, I've been running Netstumbler side by side with Kismet and it's interesting to see that Netstumbler still finds stuff that Kismet doesn't have time to get. I know multiple cards, etc would help but I'm trying to optimize what I have. Netstumbler finds from 2 to 18 additional networks per 2 hour run so it's not a huge number. That's with Kismet finding 2,500 to Netstumbler's 900 networks on that same run.
It's far better to fifle with the defaultchannels, than the channelvelocity IMHO.
I'm using a channelvelocity of 5, due to the following reason : Most AP's are setup to send a beacon every 100 msec, i.e. 10 beacons pr second. With a channelvelocity of 5, you have a chance of receiving up to 2 beacons pr channel during that 1 second timeslot, thereby increasing the chance of receiving a complete unmangled beacon or datapacket on each of those channels that are scanned in the timeslot.
If anything I wouldn't increase the channelvelocity, but decrease it. But it all boils down to how fast you are moving ofcourse.
With regards to the defaultchannels, I'm using this order : 1,6,11,7,13,2,8,1,6,11,3,4,1,6,11,9,10,11,6,1,1,6,11,5,12. The observant reader will notice that I've included 1,6,11 in each pair of 5 channels, so each "timeslot" contains the 3 channels most often used. This means that a scan where all channels has been listened to, would take 5 seconds.
With the speedlimit in the city being 50 km/h, and the actual attainable driving speed in the city being around 35-40 km/h during the day, it would mean that I'd at maximum would move 69.44 meters, but normally around 48.61 meters between each complete allchannel scan, giving me a fair chance for being inside the range of AP's no matter what channel they are using, during that 5 second timecycle.
This setup works fine for me, but as usual YMMV..
Dutch
P.S. For the metric challenged among you colonials, 50 km/h = 31.1 mph, 35 km/h = 21.7 mph and 40 km/h = 24.9 mph.
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