Which of the following applies when the FCC rules designate the amateur service as a secondary user on a band?
Amateur stations must record the call sign of the primary service station before operating on a frequency assigned to that station
Amateur stations may use the band only during emergencies
Amateur stations must not cause harmful interference to primary users and must accept interference from primary users✓Correct answer
Amateur stations may only operate during specific hours of the day, while primary users are permitted 24-hour use of the band
Explanation
Secondary status is about interference precedence, not about time of day, logging or emergencies. The amateur station simply has to yield: it may not cause harmful interference to the primary service and has no protection from interference the primary service causes.