"Roy Lewallen" wrote in message
...
Jerry wrote:

I am not smart enough to analyze the effects of rotating a dipole with
DC applied to it, but I have doubts that it would create a "far field".
Did you guys ever figure out how the "DC dipole" generates a Far Field?

Jerry KD6JDJ

It requires energy to create a far field, since the far field is a form of
energy. I explained why I thought power might be consumed by the
antenna -- current would flow due to coupling with the field still present
from previous positions (although I mentioned alternating current while
Chris correctly pointed out that it would have to be DC). I don't see any
problem with conversion of the DC into AC. It's done all the time with
spinning magnets -- look at the alternator in your car for example. And in
times of yore, RF was generated directly with high speed alternators. The
principle is very similar to, if not exactly the same as, the scheme I
described.

The whole thing is just a mental exercise to help gain a better
understanding of the nature of a circularly polarized field.

Roy Lewallen, W7EL

Hi Roy

When you write "current would flow due to coupling with the field still
present from previous positions", do you submit that more power is required
to rotate a dipole with no DC on it than one with DC on it?

I will respectfully submit that a car alternator doesnt so much spin a
magmetic field as it Rotates the field past a conductor. A car alternator
is a lumpy magnetic field that is spun past stationary coils of wire. There
is no misunderstanding about inductive coupling of close by conductors. My
question related to far field "radiation". I am aware that my understanding
of far Field radiation is very limited, so i dont propose that i have
answers. I do have question about generating a far field by spinning a DC
excited dipole.

Jerry KD6JDJ