- Tuning unit for BC-191 and BC-375 airborne
transmitters, 1.5...3.0 MHz. Used in SCR-187 and SCR-287
liaison radio sets along with BC-224 or BC-348 receivers. In
fact this particular TU-5 was made for US Signal Corps in
Ulm, Germany, after the WW II was over. The TU-5 tuning
unit is also listed
on radiomuseum.org site.