[Milsurplus] WW2 Interception Receivers

[Joe Connor]

At the beginning of WWII, the U.S. military had a radio-interception station at the Cavite naval base in the Philippines. Later, that station was moved to Malinta Tunnel on Corregidor until Corregidor fell. As I understand it, this station intercepted and decoded Japanese signal traffic.
 
What kind of receivers were used in those stations? I've read a lot about the Philippine campaign but never saw much about the technical details of these interception stations.
 
Thanks.
 
                             Joe Connor