Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?

To effectively prevent exposure to RF radiation in excess of FCC-supplied limits, amateur operators can take various actions, including relocating antennas. Moving antennas to a different location can significantly reduce radiation exposure for both the operator and the public. This is particularly important when antennas are situated close to populated areas or where there is a risk of exceeding safe exposure levels.

Relocating the transmitter, while possibly helpful in some scenarios, does not directly address the radiation emitted from antennas. Increasing the duty cycle would actually result in a higher average power output from the transmitter, which could potentially increase RF exposure rather than reduce it.

Thus, the best action among the choices provided that effectively addresses RF exposure issues is relocating antennas, making it the most appropriate response to the question.