I admit to one slight error, I said 60 Hz, when the quote you gave was 60 kHz. But the wavelength for 60 kHz is 5 km. Building efficient antennas for that might be difficult. That is building efficient directional antennas would be difficult. A directional antenna needs to be at least a quarter wavelength, and that isn't very directional. A quarter wave antenna basically has a figure 8 antenna pattern. For comparison I point to your basic outdoor TV antenna. The low end is at 54 MHz and the elements run something like 3 feet wide. For power transmission over any distance you would need highly directional antennas, which implies antennas many wavelengths in diameter, that is many km in diameter.
Having said that I have a 60 kHz receiver on my wrist. It is in a radio controlled watch that is synchronized to a 60 kHz time and frequency signal transmitted by the National Institute of Standards and Technology (NIST) in Boulder Colorado. I am rather amazed that it works at that size. They have similar systems in Europe and Japan.
Bill Gill
