any way to update this post for bt4 prefinal?

No....

-20 would be closer than -80

PWR -20 = PWR 80
PWR -80 = PWR 20

I have this adaptor, i'm looking at my airodump-ng output..

my AP has -10 while *all* others are -50 to -100.

i have the same adaptor.

i have nto tried it in bt3 yet, but you're right, bt4 does not see it..

afaik...

the -40 would mean 60
and -20 would mean 80

at least, with the Alfa 500mW b/g...