What frequencies are used for receiving HF MSI?
A.
HF MSI istransmitted on a primary frequency of518 kHz and on a secondary frequency of 490 kHz.
B.
HF MSI is transmitted on 8414.5 kHz plus one other HF frequency.
C.
HF MSI is transmitted on 4209.5 kHz.
D.
HF MSI istransmitted on certain dedicated frequencies.