Echos Around The World

On the 18th March 2018 I was up ridiculously early and couldn’t sleep, and one way I cope on the rare occasions it happens is that I will divert my mind by going and doing some ham radio. (well that’s my excuse anyway!)

So at 4am I am on 160m calling CQ and this is what I hear…

My explanation of this is that from sending the signal it has traveled around the earth and returned again to the receiver with enough delay that I am hearing my own signal. Another possibility was put forward that the signal actually traveled around the earth following the magnetic wave lines of the earth, so out into space and back. I would have thought ducting around the earth is more likely?

Any other explanation would be most interesting to hear!