(Copy of a note I sent to ON4UN which I thought might be of interest)
I've done some thinking and talking to other guys on the
East Coast and here's what I think is happening:
-it is summer in the Southern Hemisphere and there is the usual ab-
sorption associated with that.
-VK0IR does NOT experience a slow sunrise because it is summer there
(and not winter which I guess you were thinking about when you commented
on the slow sunrise). They are at ~53 South and the sun is at ~23 South,
so the sun (and absorption) rises fairly quickly. This explains why
VK0IR faded well before his sunrise (K1ZM and other guys up North
noted this since I couldn't hear him well anyway.)
-today it seemed that the station with the latest sunset to work VK0IR
was W4DR whose sunset was at 2215 (versus mine at 2230). Assuming
VK0 sunrise was 2302 today, this means that at least 47 minutes of
common darkness was necessary for the absorption to drop to the point
of allowing a QSO. This explains why only VE1/W1/W2/W3 and extreme
Northeastern W4 (Richmond, VA) were worked (because of their earlier
sunset times).
-our sunset terminator extends on a line that runs Northwest, so that
my sunset is roughly coincident with mid-Ohio, mid-Michigan and
Eastern South Carolina. It will help if you look at this on Geoclock.
-the common darkness on the path from W4ZV to VK0IR goes from 33 minutes
on January 15 to 45 minutes on January 29 (their last day?). Unless we
get some quieter conditions (i.e. less absorption), it probably means that
mid NC, eastern SC, western Virginia, mid Ohio and Michigan will probably
not get decent openings until nearer the end of their stay, and that the
guys west of that will be lucky indeed to get a QSO! Of course today
might have just been a bad day (and I sure hope it was not a GOOD day!)
-time will tell whether today was unusual but I think all of us to the
South and West on the East Coast need to pray for low absorption!
-I expect they will see this absorption problem also on the West Coast
openings which may limit working any but the extreme Northwest, unless
there is some sort of enhancement around the antipodal area (mid-VE5).
-the signal was very weak and fluttery here and I could not even
distinguish dots from dashes until about 2237 until 2250, and never well
enough to copy anything!
-as far as what this means to them, I think they will need to especially
watch the period about 20-15 minutes before their sunrise which is when
the more distant stations will have a brief window before sunrise
absorption kills them. Unless things dramatically change, I would not
expect them to work much into Georgia, Florida, Tennessee, Kentucky,
Indiana, Illinois and points farther West. They will probably work
most of the serious guys in W1, W2 and W3 fairly easily, but only parts
of W8 and W4 will make it with W5, W9 and W0 being VERY doubtful.
I hope this helps explain what's going on and I certainly hope
I will be proven wrong! Feel free to forward anything you want to them.
I'll be there every day until the bitter end if that's what it takes, hi.
73, Bill W4ZV
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