[kismac] Re: Signal strength

  • From: Robin L Darroch <robin@xxxxxxxxxxxxx>
  • To: kismac@xxxxxxxxxxxxx
  • Date: Thu, 2 Mar 2006 00:48:31 +0800

I'm not sure we'd be able to get that reliably - especially since there doesn't seem to be any consistency in what the cards report even for the same cards in different modes (c.f. AE passive and AE active - totally different signal strengths for networks that are very much "in range").

I'm all for a scientific measure *if* we can find one... but otherwise, I still think the unitless 1-100 locally auto-learned scale is the best bet.

This all sounds like an argument for using dbm if we do decide to scale. Of course, we would have to figure out how to change the raw signal value given by the card / driver into dbm.

On Feb 28, 2006, at 5:48 PM, Brad Knowles wrote:

At 6:46 AM +0800 2006-03-01, Robin L Darroch wrote:

 I agree that it should be optional, but the problem you're describing
 shouldn't be an issue unless you've *never* picked up any network other
 than your weak target network since installing that adapter in KisMAC.
 Otherwise, the weak network will still give you very low scaled
 numbers compared with the strong network that you picked up

If you're trying to help someone debug their wireless network problems and you're using their computer as part of that process, then this situation is actually quite likely.

You need to be able to use absolute mode (whatever is returned by the hardware & driver), although it might be nice to also have an auto-scaled mode.

Of course, even with auto-scaling, it may be completely inappropriate to use that for comparison between cards -- I know that on my TiBook, an Apple Airport card does quite badly, because of how and where Apple situated the antenna, and the fact that the case is now all metal.

My PowerBook G3 Pismo does much better in these cases, usually at least 30-50% better, with the exact same card, same transmitter, and same location of the computer doing the testing. When I use Senao CD 250mW Prism2.5 cards, I get much, much better signal strength in both types of computers, even though I am not yet convinced that those numbers are 100% comparable, either.

I won't get into what kinds of signal strength differences I see with all the other types of cards I have -- I've got way, way, way too many different types of cards for that.

Brad Knowles, <brad@xxxxxxxxxxxxxxxxxxx>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

    -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
    Assembly to the Governor, November 11, 1755

LOPSA member since December 2005. See <http://www.lopsa.org/>.


 Robin L. Darroch - PO Box 2715, South Hedland WA 6722 - +61 421 503 966
      robin@xxxxxxxxxxxxx - robin@xxxxxxxxxxx - robin@xxxxxxxxxxxxx

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