Topband: 160m at solar max

[Carl <k9la@gte.net>]

 Bill,

My point was simply that based on W8JI's log data there's a lot of DX to 
be worked on 160m around solar maximum, and it appears to be dependent 
on how high in latitude your paths go. I think the concept of 160m only 
being 'good' at solar minimum has been ingrained in us for many years, 
and it has become somewhat of a self-fulfilling prophecy.

It sure looks like Tom's attitude toward 160m is "damn the sunspots, 
full speed ahead." Because of this, he had over 5000 DX QSOs in nearly 
200 countries and with 40 zones around the peak of Cycle 23 when the 
smoothed sunspot number was above 100. A good question to ask is "How 
many of us thought this was even possible based on the lore we've grown 
up with over the years?"

> Your data does not include anything from the
> solar minimum years

That is correct. I have no doubt that Tom's log will show he worked 
many, many more stations during the last solar minimum than what I 
reported for the solar maximum period. In fact, in my original article 
on this topic, I even speculated that this would be the case.

> Some of the best conditions are actually just after
> the new cycle begins, when geomagnetic activity
> (Ap) is at its lowest

I have no disagreement with this, either. In fact, I've been carrying a 
plot similar to the www.spacew.com/swim/bigstorm.html data for many 
years (mine is the number of days in the month that Ap is less than or 
equal to 7 vs the smoothed sunspot number), and have discussed its 
implications to high altitude propagation numerous times.

> Just for a little more data from all areas of the world,
> here are when current 160 records were set in the
> CQ WW CW by zone

With the major contest population areas being JA, NA, and EU, I am not 
surprised that most of the records are set at solar minimum. But I think 
this data bears more looking into.

Finally, my comment about the mid and low latitude nighttime ionosphere 
not showing much difference between solar min and solar max was based on 
two facts:

1. The nighttime D and E regions are the result of sources other than 
direct solar radiation: galactic cosmic rays, EUV in starlight, and 
scattered solar radiation. So it makes sense that the nighttime D and E 
regions shouldnt depend a lot on where we are in a solar cycle.

2. Incoherent scatter radars at low latitudes show that the nighttime E 
region ionization varies very little over a solar cycle. With absorption 
occurring in the lower E region at night, it then follows that 
absorption doesn't vary a lot over a solar cycle. Again, I'm only 
talking about paths that stay at mid and low latitudes.

Carl K9LA

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