DESCRIPTION: U.S. Army Signal Corps radio set SCR-503-B. DF Receivers (BC-973, 0.1-3 Mhz; BC-1003, 0.1-1 Mhz); TM 11-246. Direction finding; designed to determine direction of radio transmitters operating within the freq of 100 kc-3000 kc which is the operating range of this set; receives CW, tone, voice. Provided understandable reception at the same time direction is being determined; 12 v storage batt provides power for the equipment through Dynamotor Unit PE-133 which provided 230 v for the rec plate supply; power required 5.3 amp at 121 DC. Uses loop antenna and telescopic sense Antenna AN-45 which extends from 16-1/2" to 9-1/2". Made by Continental Radio & Tel. Corp. Includes: Radio receiver BC-1003-B, and Loop assembly LP-33-B. Both with Serial No. 75 and Order No. 9895-SCGDL-43. WWII era. With schematic. MEASUREMENTS: 11" x 20-1/2" x 13" deep. CONDITION: Wear consistent with age.