Device to locate a wireless entry key fob

[kennedy8480]

My wireless key fob has been misplaced. I am looking for a device that will let me know when I get near it. I could use the Outback itself for that but I can't get it in the house. :-)  Does any such electronic device exist? Some sort of equivalent to an RFID reader? Also I would like to know the frequency on which the system operates. Many thanks.