<receiver picture> The receiver 'captures' the signal from the transmitter and converts it to a standard NTSC composite video out.  I've been using the receiver that came with the XCam2.
Receiver considerations and options
The stock receiver that comes with the XCam2 does a fine job of capturing the signal.  Unfortunately, without knowing the specifications on the unit, it's hard to say just how good of a job it's doing!  My future plans include hacking the receiver, perhaps with a better antenna, or an amplifier.  For now, though, it's doing ok.  Stay tuned...