via the RSGB: 8 April 2024 – HF Aurora Reflections Observed at Anchorage, Alaska USA by Whitham Reeve

Many interesting phenomena can be observed in the high frequency radio band including aurora reflections, meteor trail reflections, radio blackouts, sudden frequency deviations, aircraft reflections, and propagation anomalies due to ionospheric patches and blobs. Detections of all these phenomena at Anchorage involve a terrestrial transmitter and terrestrial receiver separated by a distance great enough to result in sky wave propagation between them.

The focus of this presentation will be aurora reflections. The terms radio aurora, aurora scattering, aurora echoes, aurora radio reflections and aurora reflections are used interchangeably to describe transmissions that originate at a distant transmitter, are reflected by high-electron-density regions associated with the aurora, and are detected by a receiver that, with the distant transmitter, form a bistatic radar. The transmissions originate at the WWV and WWVH time-frequency stations approximately 4000 km away, and the reflections are thought to occur 500 to 1000 km north of Anchorage.

This presentation follows a paper on HF meteor trail reflections and includes an overview of early investigations and concepts that underlie the observations of aurora reflections, instrumentation, and a selection of spectrum images from 2020 showing aurora reflections.