Amateurs worldwide contact and exchange QSO information with other amateurs using digital modes (Baudot RTTY, PSK, FT8, ASCII, AMTOR, Packet—attended operation only) on 80, 40, 20, 15, and 10 meter bands. Any station may work any other station. Stations may be worked once per band, regardless of mode.
ARRL官方规则和对FT8的说明
http://www.arrl.org/rtty-roundup