I'm getting WWV 10 MHz at S9 +10, which is remarkable because at a mere 75 miles (120 km) from their Tx, nearly any reception I have of this frequency is at the fringe of groundwave, with the usual weakness of signal that results. (I'm also down in a bit of a valley - I can get it better when I get up to higher altitude, even if it's an additional 8 miles from tx.) So this is skywave, and indicative that the skip zone is virtually nil. Boulder is currently reading about 8.1 MHz on foF2.