The Great Medium Wave Grey Line Challenge

By Jock Elliott, KB2GOM According to https://dx.qsl.net/propagation/greyline.html: (the image above comes from them) The grey line" is a band around the Earth that separates daylight from darkness. Propagation along the grey line is very efficient. One major reason for this is that the D layer, The grey line" is a band around the Earth that [...]