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Old May 18th 11, 11:39 PM posted to rec.radio.amateur.antenna
Cecil Moore Cecil Moore is offline
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First recorded activity by RadioBanter: Aug 2006
Posts: 572
Default Transmitter Output Impedance

On May 18, 4:05*pm, Cecil Moore wrote:
Give me some time and I will compose an example based on EZNEC results
for a lumped inductor vs a helical inductor of equal inductance. The
results are nowhere near the same.


The example is a 4 MHz series circuit with a 100v source, a 72uH
inductance, and a 2570 ohm resistor.

Using a 72uH lumped inductance, the current is the same all around the
circuit and is 0.032 amps at -24 degrees, i.e. the source current is
24 degrees out of phase with the source voltage.

Using a 72uH helical inductance, the source current is 0.039 amps at
-0.02 degrees, i.e. in phase with the source voltage. The load current
is 0.039 amps at -42.4 degrees. The phase shift through the helical
inductor is more than 40 degrees.

As you probably know, the phase angles of superposed waves have a
drastic effect on the resulting impedance.
--
73, Cecil, w5dxp.com