The resonant frequency of a Hertz antenna can be lowered by:

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Multiple Choice

The resonant frequency of a Hertz antenna can be lowered by:

An antenna’s resonant frequency is governed by its electrical length. For a Hertz antenna, resonance occurs when the radiator behaves as if its length were roughly half a wavelength. If you can’t physically lengthen the wire, you can make it electrically longer by loading it with inductance in series. That inductive loading adds reactive energy storage, effectively increasing the radiator’s electrical length, so the point where the reactive parts cancel—and hence resonance—shifts to a lower frequency. Using a capacitor in series would generally not achieve this; it introduces capacitive reactance that moves the resonance in the opposite direction or complicates the tuning. A resistor in series simply wastes power and doesn’t shift the resonant frequency. Lowering the transmitter frequency without changing the antenna’s length would also not change the antenna’s inherent resonance, it would just operate it off resonance.

An antenna’s resonant frequency is governed by its electrical length. For a Hertz antenna, resonance occurs when the radiator behaves as if its length were roughly half a wavelength. If you can’t physically lengthen the wire, you can make it electrically longer by loading it with inductance in series. That inductive loading adds reactive energy storage, effectively increasing the radiator’s electrical length, so the point where the reactive parts cancel—and hence resonance—shifts to a lower frequency.

Using a capacitor in series would generally not achieve this; it introduces capacitive reactance that moves the resonance in the opposite direction or complicates the tuning. A resistor in series simply wastes power and doesn’t shift the resonant frequency. Lowering the transmitter frequency without changing the antenna’s length would also not change the antenna’s inherent resonance, it would just operate it off resonance.

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