Why does the size of the array matter? Shouldn't you be concerned with the amount of data IN the array?
You are correct, it does not matter. I changed it to this:
if (RFID_tag[0] != ' ')
The elements of RFID_tag are initialized as ' ' after each read.
What data IS in the array?
The correct RFID tag number of 982_000109842725 is in the array.
Which pins are the XBee connected to, anyway?
I have the RFID tag read connected to RX1 (19) and TX1 (18) while the xbee is on the wireless shield which i believe is connected to RX (0) and TX (1).