Questions tagged [resonance]

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Resonant RF transformer using a piece of wire (no capacitors)

I previously posted this in electronics StackExchange here, but I believe Ham is more proper place for it as it closely relates to antennas. I'm curious if it is possible to build a spark-gap Tesla ...
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5 votes
5 answers
279 views

Does an antenna pick up signals of all frequencies or only its resonant frequency?

I heard that an antenna picks up signals of all frequencies, and then these signals are filtered by a circuit using an inductor and capacitor, and that this is how a radio is tuned. However, I also ...
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Antenna tuner at the transceiver output confusion

I am a bit confused. Let's take a HF transceiver for example. My understanding is that the output impedance of the transmitter is 50 ohms. The impedance of the coaxial cable feedline is 50 ohms, and ...
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-1 votes
2 answers
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Broadband dipole with no standing waves?

If a diode or directional coupler is fitted at the outer ends of the elements of a dipole, would this stop current reflected from the ends and so result in no standing wave on the antenna ? It can't ...
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1 answer
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Does antenna Q cause distortion?

Everyone knows that a 1/2 λ dipole has on the elements a standing wave the voltage and current of which are a bit less than 90° out of phase with each other, and the departure of this phase difference ...
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2 votes
2 answers
176 views

Why do ham radio operators say that a full wave dipole isn't resonant?

Every reputable antenna book that I've read says that dipole antennas are resonant at integer multiples of a half wave length. Wikipedia describes resonance as: the phenomenon of increased amplitude ...
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1 answer
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Is the phase difference between the voltage and current of the standing wave on a dipole antenna constant along the dipole's length?

Everyone knows that a 1/2 λ dipole antenna has on it a standing wave of RF energy the voltage and current of which are about 90° out of phase with each other. The standing wave is circulating reactive ...
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1 vote
2 answers
126 views

Does the self inductance and velocity factor of the elements of a dipole antenna change its resonant frequency?

Below are well known equations from Wikipedia for the resistance and reactance in the impedance of a dipole antenna. where $a$ is the radius of the conductors, $k$ is the wave number 2πf/c, $η_0$ ...
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