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A comment on U.S. Marine Corps Antenna Handbook (1999) [pdf]. Parent comment

Re:U.S. Marine Corps Antenna Handbook (1999) [pdf] by programmer_dude on Saturday July 29, 2023 @05:23AM (#36918408)
>The EM field is always there

Did you mean to say "the E field is always there"?

Loved this explanation otherwise.

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Re:U.S. Marine Corps Antenna Handbook (1999) [pdf] by computerfriend on Saturday July 29, 2023 @07:57AM (#36919357)
It's one field, which can be split into E and B components if you like.
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Re:U.S. Marine Corps Antenna Handbook (1999) [pdf] by georgeg23 on Saturday July 29, 2023 @09:46AM (#36920273)
The B field is just the E field's relativistic effects to an observer not in the same motion frame.

https://wikipedia.org/wiki/Classical_electromagnetism_and_sp...

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Re:U.S. Marine Corps Antenna Handbook (1999) [pdf] by H8crilA on Saturday July 29, 2023 @08:05AM (#36919427)
Both are always there if the circuit is running.

Also, both E and M fields are required to transport any power using electricity. This is also true for DC current. See https://en.wikipedia.org/wiki/Poynting_vector - the formula multiplies E by B, therefore if any of the two is zero no power (or information) transmission can occur. This is true over the air, as well as over a wire.

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