In which frequency band does a search and rescue transponder operate?

A search and rescue transponder operates in the 9 GHz frequency band. This frequency range is specifically allocated for search and rescue operations, allowing transponders to transmit signals that can be easily detected by search and rescue teams, aircraft, and vessels. Utilizing this frequency ensures effective communication and signal clarity, which is essential in emergency situations where quick location and response are critical.

The other options provided do not correspond to the designated operational frequencies for search and rescue transponders. For example, 15 MHz and 30 MHz fall into a significantly lower frequency range that is not utilized for this purpose, as these bands are employed for other radio communications, such as maritime or amateur radio. The 1.5 GHz option, while used in various communications contexts, is not the standard for the specific search and rescue transponder broadcasts. Therefore, the correct answer aligned with the function and operational requirements of search and rescue technology is 9 GHz.