Topband: 160m - better at solar max or solar min?

[k9la at frontier.com]

Eddy,
 
You said: "Perhaps high solar activity IS really & truly the bane of 160-meters, after all..."
 
That's a reasonable conclusion based solely on our observations. But it's interesting to bring some science into the picture.
 
When you look at ionization at night in the upper D region/lower E region (where absorption occurs at night), there's not much difference between solar max and solar min. In other words, solar ionizing radiation doesn't change at night between solar max and solar min. During the day is another story that we understand well.
 
But there's another source of ionization that likely affects absorption at night - it's galactic cosmic rays (GCRs). Bob NM7M (SK) believed this to be an important issue for 160m propagation - especially for extremely long distance QSOs. But GCRs appear to affect 160m in a more fundamental manner.
 
GCRs are mainly very energetic protons arriving from all directions day and night. They cause ionization down to extremely low altitudes by creating a shower of secondary particles. At solar max, when the Sun's magnetic field is strong, GCR's can't impinge on the Earth as much as at solar min, when the Sun's magnetic field is weak. So this suggests solar min will have more ionization at the low altitudes due to GCRs, which is detrimental to 160m propagation.
 
Now we just went through the deepest solar min in our lifetimes - which also means we were hit with more GCRs than ever in our recorded history (about 19% more than anything we've seen in the past 50 years). So it very well could be that this solar min was too quiet geomagnetically speaking - and it still is very quiet with Cycle 24 headed towards being an underachiever. What this implies is more absorption than the last solar min.
 
I think if we understand the processes in the atmosphere, 160m will slowly give up its secrets. This isn't going to happen overnight, as there's hardly any research down at the altitudes that impact 160m propagation.
 
I've alwaysd believed that if science and observations are in agreement, then we probably know what's going on. I see much science with respect to antenna topics on this reflector - I hope this catches on for propagation, too.
 
Carl K9LA