Abstract: This paper discusses issues related to trans-horizon high-frequency communications (HF communications) from low-level airborne platforms; specifically the Australian Army's Black Hawk helicopters. It discusses work completed and in-progress in this area, both privately and at the Australian Army's Land Engineering Agency (LEA), and brings together a number of communications-related aspects including HF propagation, antenna aspects and frequency and altitude management, all of which need to be properly managed to obtain the best HF communications from helicopters. The possible use of genetic evolution to improve antenna design is also briefly discussed.