John,
The first thing that comes to mind is whether there were any ground wave
signals mixing with sky waves during your field tests? It's been shown
that NVIS throughput can fail when the sky wave echoes interact with
ground waves. The sky waves take more time to arrive at the receiver so
To Tony (K2MO) in particular, but not exclusively:
Following your simulation results on these modes in January I have done a few
tests in the field and I have to say that I don't understand the results.
Please note that I am not trying to make a point, but to understand why the
theory does
