What is a characteristic of VHF signals received via auroral backscatter?

Auroral backscatter occurs when radio waves bounce off the highly ionized, rapidly shifting regions of the auroral borealis (Northern Lights) or aurora australis. Because this ionized curtain is in constant, chaotic motion, the reflected radio signals undergo rapid phase and amplitude changes. As a result, signals received via auroral propagation are heavily distorted, and their signal strength fluctuates wildly. Voice modes often sound garbled or like a hoarse whisper, while CW (Morse code) takes on a raspy, buzzing tone that makes it difficult to copy. Distractors such as aiming west or extreme distances are incorrect. You generally aim your antenna North (in the Northern Hemisphere) to bounce signals off the aurora, and distances are typically hundreds, not tens of thousands, of miles.