When you include the car body, it is a parallel resonant
circuit, not
series. The whip is electromagnetically coupled to the car
body and
that makes it parallel resonant. >>
What does that mean? Anything with accelerating charges is
connected to any other charge in the universe through the
effect we call electromagnetic radiation.
Are you intending to say it is connected by displacement
currents? If so, it is still a series resonant circuit! The
path is the feedpoint up through the coil, through
displacement currents to the chassis, and back to the
feedpoint.
That's a series circuit.
It's similar to taking a two element
series resonant circuit and connecting the two open ends
together. You
now have a parallel resonant circuit.>>
They aren't connected in this example. It appears what you
are actually trying to say is there is no such thing as a
series resonant circuit.
Try this:
Disconnect the whip from the car and lay it on a table. Now
it is
purely a series resonant circuit, i.e., the coil is the
inductor and
the shortened whip is the "capacitor". Now try to find a dip
at its
series resonant frequency. You will not be able to.
Of course it has no dip. It has no resonance when one end of
the coil is disconnected.
I should point out that you will be able to find a dip at
some higher
frequency where the now-disconnected whip is acting like a
dipole, but
that is not the series resonant frequency we are talking
about. As
before, that higher frequency is a parallel resonant mode
anyway.>>
I can take a resistor, a capacitor, and an inductor and
connect all three in series across a source. At a certain
frequency XL and Xc will cancel and impedance seen by the
source, assuming lossless reactive components, will be the
value of the resistor alone. Are you saying that isn't a
series circuit?
73 Tom
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