Control Unit, C-149/ARN-6 Radio Compass System, WWII B-17, B-24, B-29
This is a terrific example of a C-149 Control unit for the aircraft receiver R-101 of the Radio Compass AN/ARN-6 system for direction finding and homing. The receiver function tunes from 100-1750 kHz across 4 bands, which were selected by rotating the center knob below the frequency band window. The center knob rotates a flexible shaft connected to a rotatable loop antenna.
The AN/ARN-6 system evolved over time, originally using a control box similar to the BC-434A, and then in 1950's versions, using a smaller module (C-1514/A) without the signal strength meter integrated into the cockpit communication console with a much smaller loop antenna (AS-313) without a radome. These were made by Bendix and Magnavox, but this unit does not carry the manufacturer's name on its data label.
The AN/ARN-6 system of late WWII-vintage (see diagram), as installed in an aircraft such as the heavy bomber B-24 Liberator, B-17 Flying Fortress, B-29 Superfortress, and medium bombers and transport aircraft, typically consisted of the following components:
- Radio Compass Unit R-101/ARN-6
- Mounting MT-274/ARN-6
- Indicator ID-91/ARN-6
- Indicator ID-92/ARN-6
- Coupling Unit CU-65/ARN-6 (2)
- Control Box C-149/ARN-6
- Loop Antenna AS-.141/ARN-6