Re: Re: Differences in iwspy !!!

Eric Brombaugh said:
> If I recall correctly, this issue has been around for a while and is
> fairly well known - it even shows up in some widely published Linux/WiFi
> buglists. The basic problem is that _every_ WLAN card manufacturer uses
> a different metric for reporting signal & noise power. Consequently, the
> power numbers you get from the cards are not apples/apples and need to
> be recalibrated depending on who made them. Adding that capability to
> the WLAN drivers is not considered critical since it doesn't have any
> noticable effect on data traffic.
>
> I used to work at a (then) major WLAN silicon mfg and can confirm that
> the firmware/driver guys didn't put a lot of emphasis on the accuracy of
> these measurments, nor did they devote much time to ensuring that the
> measurements were consistent across product lines or across the industry
> in general.

The firmware/driver guys were right to not be concerned; I used to work
for an RF manufacturing company in Prod. testing/R&D -- you are not
getting a piece of test equipment when you buy a wireless card.  You
should be grateful for whatever information you get beyond "red, yellow,
or green."

Not that I don't think it'd be cool to have a better measurement
situation, but I'm not expecting too much!

Same thing with battery meters, actually.

Just my 2 cents.


Phil Mendelsohn

-- 
Dept. of Mathematics, 342 Machray Hall
U. of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
Office:  446 Machray Hall, 204-474-6470
http://www.rephil.org/   phil at rephil dot org