I'd like to buy one XBee Pro with Wire Antenna, and another with an u.fl connector. The problem is that, on the only website I can buy them, the U.Fl one costs 20 € less than the one with a Wire Antenna: I wish I could keep these 20 bucks.
On the other hand, I've already got two unused XBee with Wire Antenna: I wonder whether I could unsolder the U.Fl connector of one XBee Pro, and instead solder the wire antenna of one unused XBee.
So, Could I just replace an U.Fl connector with a Wire Antenna ? Won't this lower the range ? Are the XBee w/ ufl connector different from XBee w/ wire antenna, except for the antenna/connector ?
The main consideration here is the frequency of operation - if the unused XBee and the one with the U.FL connection operate at the same frequency, you'll be fine. It won't make an appreciable difference whether you attach a U.FL antenna or if you solder the other wire antenna on.
See here for a similar answer.