Atheros - txpower - Compex WLM54AG + WLM54AG-23

Johann Hugo jhugo at
Thu Feb 15 12:26:33 UTC 2007

On Wednesday 14 February 2007 19:09, Sam Leffler wrote:
> Johann Hugo wrote:
> > I'm busy testing two wifi cards from Compex under FreeBSD 6.2-STABLE. The
> > WLM54AG card has a max txpower of 20dBm and the WLM54AG-23 has a max
> > txpower of 23dBm.
> >
> >
> > The problem is that both cards produces the same RSSI value on my remote
> > station a couple of km's away from my test setup. If I do the same test
> > with the same cards under Ubuntu 6.06 then the  WLM54AG-23 produces a
> > bigger RSSI value on my remote station than the WLM54AG card.
> Beware that rssi isn't necessarily indicative of tx power.  If you don't
> put the cards on a spectrum analyzer or power meter you're just guessing.
I'll try to get my hands on a SA or power meter.

> > Under FreeBSD, with a country code of 710 the max txpower can only go
> > up-to 32 (16dbm) on both cards and vith a country code of 0 they can go
> > upto 36 (18dbm). Under Ubunti I can set the max txpower of the WLM54AG
> > card to 20dBm and the WLM54AG-23 card to 23dBm.
> Where do you get these numbers?  
These are the reported values from ifconfig / iwconfig

> There was a hal bug I recently fixed 
> where the _reported_ max tx power obtained from the calibration data was
> wrong.  Note that is REPORTED, the actual max tx power cap was correct
> and you should see that measuring with a SA or power meter.
The Ubuntu drivers comes from Compex (when I first reported the problem with 
them) with an old HAL I think. On FreeBSD I'm using

> > I'm not to sure if this is the right place to post my problem, or whether
> > I should rather try the MadWifi list or the manufacturer of the cards
> > itself, but it feels like it's related to FreeBSD.
> It is unclear what is going on but there have been no hal changes that
> would affect operation and/or cause operation to be different between
> madwifi and freebsd.  I suggest you measure things properly and then
> come back to me.
Will do.


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