Repair a xbee wire antenna?
Wire antennas at the simplest level are essentially just a conductor of a specific length, which has a relation to the wavelength of the signal they are designed to transmit / receive. 

If the wire antenna itself is not broken, merely broken off the little XBee board, then repairing it involves soldering the connector at the base of the antenna back onto the solder area that it has broken off from.

If however the antenna has "broken", literally, then: 


Obtain a length of nice thick wire (stiff chrome wire or spring wire works for me) 
Cut it to match the length of the original antenna as closely as possible - or twice its length would work too
Cover one end of the wire with a blob of epoxy glue to protect your fingers from getting perforated later
Pre-apply solder to the other end, using flux - Chrome wire, for instance, doesn't take solder easily
Once done, solder that end onto the pad on the Xbee that the original antenna used to be connected to. Use a fine-tip soldering iron for convenience.
Check, it should be working now.


I have had RF modules (not tried with the XBee yet) that work, with greatly reduced range, even with the antenna not connected, so testing whether the XBee itself is fine is easy enough even before adding the replacement antenna.