Who must designate the station control operator?

According to FCC rules, the station licensee is the person legally responsible for the proper operation of the station and therefore has the sole authority to designate the control operator. If the licensee operates the equipment themselves, they are simultaneously the licensee and the control operator. If a guest operator uses the station, the station licensee must explicitly designate them as the control operator. Neither the FCC nor a frequency coordinator plays a role in choosing or designating who operates a specific private amateur station.