Topband: Unusual Propagation

[Dennis OConnor]

Working on antennas today I had the receiver on the Beverages... In the shack testing the switching I thought I heard a call and turned the audio up...Between 2030Z and 2034Z I heard clearly 3 DX stations  - G3PQA  S53O  and  ON6_AU - from Michigan (en73vk) 
 
THe first two on 1813.7 and the other at 1816.6...  (I did copy the ON clearly but didn't write the calls down immediately, went to the field again and when I got back I have forgotten the one letter)
Anyway, my sun was still over 2 hours from sunset, being 30+ degrees up in the sky...
The band was very quiet and the signals were right at the noise level but Q5...  I'm not sure how the signals got here - ducting above the D layer?

denny / k8do