"W5DXP" napisal w wiadomosci
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On Wednesday, July 25, 2012 3:11:31 AM UTC-5, Szczepan Bialek wrote:
So: enters in = radiates from;?

To the extent that RF energy penetrates to a skin effect depth, the
conductor is not perfect and dissipates some of the power. All real-world
antennas dissipate some of the RF power in I^2*R (and possibly dielectric)
losses. In an efficient antenna, most of the system energy is "lost" in
space as coherent radiation.

When the free electrons in a conductor are acting as a bucket brigade for
the RF fields/waves/photons, they are essentially vibrating in place
because of their very slow drift velocity. Those I^2*R losses in the wire
are due to coherent RF photons that are absorbed by electrons and not
re-emitted as coherent RF photons but are instead converted to heat energy,
the price that Mother Nature requires be paid for all that vibration. In an
antenna that is 90% efficient, 10% of the coherent RF energy is converted
into non-coherent heat energy. That's the energy that Poynting was talking
about.

Pointing was writting in 1884. He described the DC current.
His result is caused by the assumption that the Biot-Savart law is right. Is
it?
S*