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October 10th 03, 05:36 PM

On 10 Oct 2003 08:06:45 -0700, (Art Unwin KB9MZ)
wrote:
Richard,
If I have a loop circuit unconnected to a transmitter
could it not oscillate under ideal conditions?
If it can then would it not radiate at the frequency
that it is resonant at as well as reradiate at the
frequency of the energy input
Regards
Art

Hi Art,

Distinguish between what resonates and what oscillates. Passive
circuits do not oscillate even though they support the flow of
alternating current. The ideal conditions for oscillation is the
presence of a power source, gain, and feedback. If any of the three
is missing, then there is no oscillation. The ideal conditions for
resonance is an external source of alternating current coupled to a
system that is harmonically related. If that system has no harmonic
relation, then there is no oscillation or resonation.

ALL systems that support the flow of alternating current radiate. How
well this is performed is called efficiency.

You cannot change a frequency without a nonlinear interface (like a
diode) or without the original excitation source containing spurs
(illegal at the antenna).

73's
Richard Clark, KB7QHC