# Questions tagged [waves]

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### How can an RF coil emit at 3 different frequencies at the same time during Amplitude Modulation?

This image shows how an AM wave is generated and emitted: This comment explains how 3 separate waves are sent at once to represent an AM wave: the transmitter does not transmit one pure sine wave at ...
• 203
169 views

### Why does a sine wave show two peaks in the frequency domain on GNUradio?

I constructed the flow graph in GNUradio 3.7 as below: I know a sine wave has only one frequency, so what causes the frequency sink to show two peaks?
• 604
88 views

### 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 ...
• 3,323
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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 ...
• 3,323
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### 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 ...
• 3,323
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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 ...
• 3,323
1 vote
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, $η_0$ ...