3500-3800 KHz (3.5-3.8 MHz) or the 80 m band
The lowest HF band is similar to 160 m in many respects. Daytime absorption is significant, but not quite as extreme as at 1.8 MHz. High-angle signals may penetrate to the E and F layers. Daytime communication range is typically limited to 400 km, primarily via ground-wave propagation. At night, signals are often propagated halfway around the world. As at 1.8 MHz, atmospheric noise is a nuisance, making winter the most attractive season for the 80 m Dxer.

Source: ARRL Handbook, 1993