On 1/31/2012 3:10 AM, Pete Smith N4ZR wrote:
> Jim's original cookbook used multiple cores in each.
There are two good reasons for using multiple cores. One is power
handling. The other is to get enough L and C to move the resonance low
enough to cover the frequency range of interest. L increases as the
square of the number of turns, C increases as the number of turns (not
squared). Both lower the resonance. The impedance at resonance also
increases with the number of turns -- not linear, not squared, because
resonance is moving down. At any given frequency, the resistance coupled
from the core DOES increase as the square of the number of turns.
73, Jim K9YC
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