Wifi signal level differences

[nick@nhthomas.freeserve.co.uk]

Hi,

I have an Atheros ath6kl_usb based wifi dongle.
I am using it with an embedded project.

The driver code can be built for either X86 or sh4 hardware - so I can also use the same USB wifi dongle on my Fedora 12 Linux PC or plugged in to the embedded device.
It's working fine in both situations.

But, I notice that the signal level reported in /proc/net/wireless is slightly different between the two units.
Note, I am using the same physical Atheros wifi dongle, and moving it from one device to the other to this test.

I notice that when using the X86 PC I see a signal level of -61, which is marginally better than the -66 I see in the embedded device.

I know that this isn't an exact science - but using a short USB extension lead I can orientate the wifi dongle to be in the same place and orientation when plugged in to either device.
So, I would expect the wifi signal strength to be reported the same !?

I know there are many differences between my Fedora 12 PC, and the embedded STLinux project - not least that the driver is compiled using different compilers.

But, I was wondering what else could explain the difference in signal levels between the two?

Also, which part of the driver code is responsible for reading/calculating the signal level value?


Regards

Nick