MHFCS-constraints on operational frequencies

This paper provides a look at the modernised high frequency communications system (MHFCS) from a frequency management perspective. The MHFCS seeks to replace the existing single service HF facilities of the Australian Department of Defence with a nation-wide network of distributed high frequency (HF) transmit and receive sites interconnected by a wide area network. The paper discusses the high frequency (HF) spectrum needs of a communication system comprising a virtual HF network made up of four nodes geographically dispersed over the Australian continent which provides coverage to 2000 nautical miles. The MHFCS will utilise automatic link establishment to support a modem HF capability on modified mobile platforms whilst simultaneously supporting existing legacy services. Specifically it addresses the changes that will need to occur in spectrum allocation in moving from an existing capability which relies on single service operations to one which provides a joint capability utilising adaptive HF techniques.