What is required before an amateur station can operate on a specific frequency?

A license from the FCC is required before an amateur station can operate on a specific frequency because the Federal Communications Commission (FCC) regulates the use of radio frequencies to ensure orderly use and prevent interference among users. Each amateur operator must obtain a license which confirms they have passed the necessary examinations that demonstrate their knowledge of operating procedures, regulations, and the technical aspects of amateur radio. This licensing process is essential as it contributes to the responsible and efficient use of the radio spectrum, allowing operators to engage in communications while upholding standards set forth by the FCC.

The other options presented relate to aspects that may be considered in specific scenarios or to facilitate better frequency use but do not serve as a primary prerequisite for operating on a frequency. For instance, frequency coordination may be necessary in certain bands to minimize interference among multiple operators, but it does not replace the requirement for an FCC license. Similarly, receiving authorization from other operators, while a good practice in some contexts, cannot substitute for obtaining the official licensing from the FCC to operate legally. Lastly, stating that there are no requirements overlooks the fundamental necessity of having a license, which is mandated by federal regulations.