I have this card as well, as far as I've been able to find, an iwlist power setting of 19 should be full power. It seems that Ubiquiti programmed the card to 'lie' about its power setting, because some programs would limit it. So a setting of 19db would be spoofed to something like 10db less than its actual setting. I too would be interested in a confirmation of this, or specifics.
so with an iwconfig ? or ifconfig ? and than how to correct the rate ??
by the way I bought his card which seemsto be even more powerfull than the Ubiquity (I am very disapointed by Ubiquity)
"the UsB Alfa Network highpower adapter" its given for 500mv
data-alliance.net (vey fast delivery)