Airport more "sensitive" since upgrade

Since I upgraded to Leopard it seems my Airport signal strength has "weakened". I used to go almost anywhere in my house and get full bars of reception. Now (not sure it's due to upgrade, just noticed that it's been since upgrade) I can't seem to even get full bars when sitting at desk next to router.

Anyone else experience this? Know what might be the problem? Coincidence with Leopard upgrade with other solution? Or are they indeed linked?

Thanks.

I noticed this when I upgraded,
I used to allways get full bars and sometimes now I am only getting two or three
However, now that I am typing this I have full bars
Maby apple has chaned the way it displays the "signal strenght"