I became curious about this and went to the book to learn more. The system proposed in the book is capable of radiating around 2.2 x 10^-29 W by rotating a bar weighing 500 tonnes about 270 times per minute.

[1] Source: Kraus, J. D. (1988). Antennas (2nd ed., p. 769). Retrieved from https://ia802907.us.archive.org/8/items/KrausAntennas19882ed...