From the makers of the GPR-90 receiver

The STR-5 is a fixed frequency receiver, 19" wide and a couple of
inches high. It is fixed frequency which can be changed by plugging in
another tuning drawer assembly into a drawer. The new assembly has a
crystal oven, and slides into a slot, and then makes contact.
This is very very rare. I do not have the power cord which uses the
usual Milspec type connector. I have not tested it, so sold as-is, but
appears complete.
I'm selling one receiver with one tuning drawer. I believe this is
either (1) Canadian Mil surplus, or (2) from the old NORAD Cheyenne
Mountain facility.

Here's the spec sheet:
http://www.geocities.com/vintagetmc/str5-1.html

BTW, that's the super TMC website that has almost the entire TMC
history

$375 plus shipping