The implications and applicability of a QAM high data rate modem

The art of designing successful HF communications systems is growing more complex but with much greater dividends. Many new technologies are now available. Traditional 75 bps broadcast data links are giving way to 19.2 kbps data links using commercial off the shelf HF radios. The developments in STANAG 5066 and Mil Std 188-110B have produced waveforms that allow user data rates up to 9600 bps in a single 3 kHz sideband (SSB) and 19.2 kbps in independent sideband (ISB). This paper reflects on the issues and data collected from actual over-the-air (OTA) testing. These tests measured characteristics over HF skywave paths between Cedar Rapids, Iowa, Ottawa, Canada (1336 km) and San Diego, California (2467 km)