A comparison of HF radio digital protocols

The amateur radio community traditionally has supplied backup communications for the Federal and amateur radio emergency response communities. In the interest of developing this resource, the National Communications System (NCS) sponsored the National Telecommunications and Information Administration (NTIA) to test various HF modems to establish a technical baseline of standardized performance data on HF modem protocols. It is intended that the Federal Emergency Management Agency (FEMA) use these test results to determine the protocols that could serve as an interchange with the amateur community in the event of a national emergency. The tests were conducted at NTIA´s Institute for Telecommunication Sciences (ITS) laboratories in Boulder, Colorado. The controlled laboratory conditions enabled ITS to test the protocols under a well-defined, repeatable set of simulated ionospheric channel conditions. Although the extreme limits of degraded channel conditions used to test each protocol varied according to the robustness and implementation of the protocol, all of the protocols were subjected to the same set of degraded conditions. The performance of the various modems and their protocols were compared under the same conditions, establishing a baseline of modem protocol performance. Throughput was used to evaluate the performance characteristics of the tested modem protocols