DESIGN OF A LONG RANGE COGNITIVE HF RADIO WITH A TUNED COMPACT ANTENNA

Abstract

High frequency (HF) communications, ranging from 3 to 30 MHz, are utilized by many radio enthusiasts to conduct transmissions with users across the globe. These communications depend on successfully reflecting signals off of the ionosphere. However, numerous factors (i.e. power level, coding, modulation, etc.), combined with the instability of the ionosphere, can make transmissions over this frequency band unreliable. Thus, an HF communication system design is proposed to offer more robust long range HF communications. The system has a cognitive engine that can determine transmission parameters (i.e. coding, modulation, etc.) capable of providing a high throughput and low bit error rate in various environments. The system also has a low-profile helical antenna that, combined with a matching circuit, is capable of receiving signals over different subsets of the HF band. These two components constitute a system capable of effectively transmitting and receiving signals over the HF band.