Sometimes, aurora evolves into Auroral E at 50 MHz (and occasionally at 144 MHz). The doppler distortion associated with aurora propagation disappears and signals become clear, very much resembling the characteristics of Sporadic E. Often the signals do have a slighlty hollow sound to them and buld slowly over time. Antenna headings also suddenly shift to great circle headings as opposed to generally northward toward the auroral curtain. Single hop distances of up to 1400 miles are the norm, but at 50 MHz double hop contacts out to 3100 miles have been made.
Auroral E typically occurs over the northern third of the US and southern Canada as auroral activity is diminishing. This most often happens after midnight on the eastern end of the path (Editor's note: although I remember one tremendous 144 MHz auroral E event in 1989 that occurred much earlier in the evening... it was fantastic!). Most reported auroral E contacts have been on east-west paths.
As in the great opening of March 1989, auroral E can appear while intense auroras are still in progress. During that opening, stations in the southern US were able to make 50 MHz contacts, and there was a 144 MHz opening from the northeast to the midwestern US. Extremely strong auroral E signals instantly appeared on 144 MHz at a time when the aurora was fading but still in progress.
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