7-12B2 C
 Why is an antenna coupler/tuner required for MF-HF transmissions?
A. The antenna coupler/tuner calculates the proper spectrum band for the operator to use.
B. To ensure transmissions are restricted to legal marine frequencies.
C. The length of the physically-fixed antenna must be electrically matched to the intended frequency of operation.
D. The antenna coupler/tuner indicates whether the ionosphere is ready to reflect a transmission properly.
