[kismac] Re: Signal strength

  • From: Jim Selby <jim@xxxxxxxxxxxx>
  • To: kismac@xxxxxxxxxxxxx
  • Date: Wed, 1 Mar 2006 11:53:57 -0700

Actually there is a formula for converting the Apple airport numbers to dBm's - This is done with Apple's Airport Client Monitor.app (attached)

I know one of the engineers and he gave me the formula years ago - I will try to contact them.

This formula has been used in the old Karlnet Configurator applications too - Karlnet was acquired and dissolved but I still have some old contacts.  It was a nice application that it had a preference option of showing either value.  As a wireless professional - I would LOVE to see KisMac utilize dbm as I use these values to determine data rates and receive sensitivities.

I will look into and reply back if I get the formula.


Jim Selby | CEO | Aspen Wireless Technologies, LLC | click for vCard

“in a Digital Revolution, Mr. Selby is a Kind of Wireless Guerrilla” - Wall Street Journal

On Mar 1, 2006, at 10:20 AM, Brad Knowles wrote:

At 12:48 AM +0800 2006-03-02, Robin L Darroch wrote:

 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

I agree, that's going to be one hell of a challenge.

 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.

Whatever numbers are produced, regardless of all proscriptions against such behaviour, people are going to use them for comparison purposes, and then they are going to get mightily confused.  In FreeBSD parlance, this would be a serious violation of POLA (Principle of Least Astonishment).

If we can't reliably convert whatever numbers are given to us by the driver to a useful scale like dBm, I think we're better off not trying to further interpret whatever numbers the driver does give us. Yes, we should auto-scale the graphics to suit, but let's not make the mistake of auto-scaling the numbers themselves.

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/>.

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