Topband: JT Path - Too Much Darkness for LP?

[btippett@alum.mit.edu (Bill Tippett)]

        We discussed long paths to death in September so I'm not going
to repeat myself...see the following for more info:

http://lists.contesting.com/pipermail/topband/2001-September/013347.html
http://lists.contesting.com/pipermail/topband/2001-September/013368.html
http://lists.contesting.com/pipermail/topband/2001-September/013411.html
http://lists.contesting.com/pipermail/topband/2001-September/013414.html

        However, I find myself wondering why the JT1/K4ZW signal is much
weaker than expected on 160.  Here's an idea I've been thinking about.

        Assuming the long path mode has some dependence on relative 
daylight for enhancement, I'm wondering if we have too much common darkness
on this path at this time of year.  Checking my previous 160 long path
QSO's, here's the common darkness for the following QSO's:

QSO                     Date       Common Darkness      Path
UA9UCO - W0ZV           29SEP87         59 mins         Sunrise
JJ1VKL/4S7 - W0ZV       28DEC91        109              Sunrise
3W5FM - W4ZV            06JAN00        107              Sunrise
XZ0A - W4ZV             21JAN00         62              Sunrise
9V1XQ - W4ZV            13JAN96         42              Sunset
S21XX - W4ZV            04FEB97        106              Sunset

        Here's common darkness for my long path possiblities to JT:

Sunrise - 172 mins
Sunset  - 115 mins.

Indeed I have heard Ken 449 at my sunset and only a whisper at my sunrise.
I have a feeling I have a better chance at my sunset because we are not 
getting enough enhancement to make the path work on 160 as well as it would
with relatively less common darknesss.  Although inconclusive, this seems
to again point to some sort of daylight-induced enhancement making long
path possible.  BTW, 80 meters is another ballgame because absorption is
much less.  I have made numerous 80M long path QSO's with over 3 hours of
common darkness...in fact today, Ken had a very readable signal on the
SSW long path.  

        For what it's worth...I'm going to keep looking on both paths but
my guess is that a QSO will be on the evening path.  My comments apply
only for my QTH and I would expect guys in the Midwest will have a decent
chance on their sunrise long path.

                                                73,  Bill  W4ZV

P.S.  DX-Aid plots of the above QSO's at:
http://users.vnet.net/btippett/dx_aid_plots.htm