GTE Sylvania R-1621/:UR Surveillance Receiver

R-1621 (XE-1) /UR Surveillance Receiver, VN-Era, GTE Sylvania MFG. SN 14! 20-80 MHz, All Mode, with Pan Display, and 4 Preset channels. Would like any information, or manuals for this unit. How was it used? What are the power requirements? If you can't live without it, you may own it for $1500 or an interesting trade :)