Questions tagged [waves]
The waves tag has no usage guidance.
14
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Wave bounce inside a resonant antenna
Let's assume we have a transmitter, a feed line, and a standing wave antenna (dipole, etc.). The transmitter is matched with the feed line, and the feed line is matched with the antenna, which is why ...
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How to calculate phase constant for a coaxial cable?
inner and outer conductor diameters of 1 mm and 5 mm respectively, is filled
with a non-magnetic PTFE dielectric having εr = 2.55. frequency = 1 GHz.
- 21
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Waveguide size for 2.4 GHz
I'm thinking to make a wave guide that has diameter 1/8 of the wave length.
At 2400mhz the full wave length is about 125mm.
I have aluminum pipe that is 16mm. So 8*16 = 128mm (very close to 125mm).
If ...
- 13
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Is a 1/2-wave coax cable shorter or longer than the full-speed 1/2-wavelength?
If I want to cut a half wavelength segment of coax for the two-meter band and the velocity factor is 85%, is my cable going to be shorter or longer than a meter?
I'm trying to figure out if the ...
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Why can a monopole antenna receive wavelengths significantly longer than its physical length?
I am new to ham radio and have been playing with a RTL-SDR receiver to which I have connected a vertical 1.5m monopole antenna.
However, I can receive transmissions belonging to the 40m band (albeit ...
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4
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Would it be possible to light up a bulb wired one side to a transmitting antenna?
Would a light bulb light up if wired to the end on an antenna ?
If you would connect a light bulb on one of its poles to a quarter wave antenna like
in the schematics below, would the bulb light up ...
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3
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Wavepropagation through air - EMC test values 100V/m
I am reading the Automotive International standards ISO 11452 and it states that I must have a chamber in which I must generate 100V/m on a range of frequency.
My question is: In which circumstances ...
- 11
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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 ...
- 311
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2
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665
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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?
- 600
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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 ...
- 3,665
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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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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 ...
- 3,665
0
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2
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115
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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 ...
- 3,665
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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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