AN/ARC-27

The AN/ARC-27 is an airborne UHF communications system, that was used in many U.S. aircraft of the 1940s and 1950s, such as the A-3A/B, A-4, B-47, B-50, B-52, B-66, F-8A, F-86, F-89, C-97, C-118, C-119, C-121, C-124, C-130, H-19, H-21, T-28, T-33, T-39, X-21, AF-2W, F2H-2/2N/2P, P2V-5, F3D-2 and F9F-2.

System Description
The ARC-27 was a military UHF AM radio that operated between 225.0-399.9 MHz and transmitted at 9 watts. It featured a separate guard receiver for monitoring 243 MHz, while simultaneously monitoring the active channel selected. The radio utilized electron tubes and was pressurized to prevent electrical arcing at high altitudes.