Experiences from HF interference measurements in Sweden

The Swedish Defence Material Administration is currently planning the procurement of an HF radio system for the Swedish Armed Forces, KV 90. Interference measurements in the HF band, which will be used in the KV 90 tender evaluation process to compare different proposals concerning robustness against interference, are reported. A mathematical expression which takes system parameters as input and gives the interference experienced by the system as a result is suggested. Measurements were made to gain knowledge of how receiver bandwidth affects the percentage of interfered channels in an HF radio system. The correlation between interference patterns at different locations was also studied. The results show high correlation for distances up to at least 500 km