Since krokus didn't answer, I will
HF propagation is heavily dependent on solar activity, and also the season. In general, you would need to stay below 10 Mhz during the evening, above that during the day.
This is because the D region of the ionosphere (roughly 40 miles above the surface) absorbs low frequency RF during the day, as it is created by the sun's rays. When the sun sets, the D layer disappears, making lower frequency reception possible.
That being said, 8 Mhz MIGHT propagate if conditions allow it during the day. This is because during the winter months, the amount of sun we get is somewhat less (even though we are closer to the sun by about 1.5 million miles, our axis is tilted away). This should not be counted on as a certainty, however. If there is activity relatively near you on 8 Mhz, you may have a shot at this
If you get serious in the world of HF, a basic understanding of propagation is a must. You don't need a degree in solar physics to grasp the basics. Even a basic course in amateur radio will include instruction on this.
Mike
