Anomalous propagation behavior of radio signals at high latitudes

Signals in the 3 to 30 MHz (HF) band propagated through polar and auroral ionospheric regions sometimes undergo some unique and profound changes. The channel capacity, intelligibility and reliability of these signals are affected by multipath distortion, backscatter, nongreat circle propagation and other high latitude anomalies. Signals propagated in the very low frequencies (VLF), low frequencies (LF), medium frequencies (MF), very high frequencies (VHF)/ultrahigh frequencies (UHF) and microwave portions of the radio spectrum also undergo some very deleterious effects. Specifically, some of the newer results obtained include: ground constant measurements of tundra permafrost, MF skywave signals and precipitation depolarization of satellite downlink signals.