<Here are some very basic *general* laws.
Es occurs 9am to 9pm. Tropo 9pm to 9am. >
I have to dispute this. It simply isn't supportable. I have at many times and in many locations observed DX via these modes at almost any time of the day, and I've seen numerous reports from others as well.
One might be able to say that Es occurs more frequently within the hours noted above, but one could not say the same for tropo events, as I can vividly recall tropo events over the years where the tropo persisted 24/7 for 2 or 3 days.
15 mi NW Philadelphia, PA
WB2BJH -- Grid FN20id
Yamaha T-80 & Conrad RDS Manager;
Yamaha T-85 & Conrad RDS Manager;
Onkyo T450RDS; 4) Tecsun PL-310;
Sony XDR-S3; Sony ICF2010; all w/ APS-9B @ 15';
2) Sony ICF2010 barefoot w/ whip