Portable HF Antennas for Concurrent Multiband Systems

Abstract: Current HF communication systems are confined to transmit in relatively narrow frequency band of a few 100 kHz at the time. The problems with limited bandwidth accumulate in HF-networks with multiple links and such networks are therefore hardly “internet capable” today. Previously, systems using channel aggregation over narrow channels in multiple frequency bands have been proposed to increase the capacity and reliability of the system by exploiting current propagation conditions in a better way. An interesting implementational problem is the design of practical and efficient antennas for concurrent multiband transmission in HF. Constraints like complexity, size and ease of deployment are considered. Some classical wideband aperiodic schemes are compared with switchable multiband solutions that cover a limited number of adjacent bands. Designs, simulations and some early field test results are presented. Finally, implementation aspects and constraints are discussed.