5MHz Doppler shows travelling ionospheric waves

摘要

This was an experiment carried-out within the terms of the Notice-of-Variation under which UK amateurs were able to use frequencies in the 5MHz band during the period August 2002 - July 2006. This particular experiment could not have been done on 3.5MHz because the E-layer reflects at that frequency during the midday period and this layer does not exhibit significant Doppler shift. Nor could it have been done on 7MHz because the F-layer does not always reflect at vertical incidence during a typical day.