1. Is the Nyquist theorem true for high-quality single-mode optical fiber or only for copper wire? 2. . Radio antennas often work best when the diameter of the antenna is equal to the wavelength of...

1. Is the Nyquist theorem true for high-quality single-mode optical fiber or only for copper wire?

2. . Radio antennas often work best when the diameter of the antenna is equal to the wavelength of the radio wave. Reasonable antennas range from 1 cm to 5 meters in diameter. What frequency range does this cover?