All Questions
10
questions
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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 ...
- 145
1
vote
0
answers
54
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Which terms in the equations for dipole impedance include inductance/capacitance and velocity factor?
In the below equations for the impedance of a center fed half wave dipole, exactly which terms include self inductance/capacitance, and which terms cater for an antenna embedded in a homogeneous and ...
- 145
0
votes
1
answer
31
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Is self-inductance and velocity factor included in equations for half wave dipole imdedance?
Can anyone tell me if the equations below for the impedance at the center feed points of a half wave dipole include terms for self inductance and velocity factor of the elements, and if so provide an ...
- 145
0
votes
2
answers
94
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What is the diff in operational range underwater between a dipole trimmed to resonate @2.45GHz versus a dipole tuned to resonate using a pi network?
(Sorry about the use of "diff", but I needed the characters.)
In air, a half-wave dipole can be physically trimmed to resonance and will radiate well.
It can also be tuned using a pi network ...
1
vote
1
answer
126
views
What is a resonance element?
I'm looking at a horn antenna and why its a good addition to a waveguide. I've read that the horn can operate at a wide range of frequencies since it has no resonant element. But I can't find a good ...
- 433
0
votes
2
answers
770
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Exactly what is the cause for the zero reactance seen in the impedance at the center feed point of a resonant half wave dipole?
Lots of explanations i've read on the internet written by ham radio operators and in some text books state that a half wave dipole is resonant when the inductive and capacitive reactances cancel out. ...
- 145
2
votes
1
answer
2k
views
Standing waves in antenna: why is the current wave symmetric with respect to the centre?
In trasmitting antennas the current is described with a standing wave (in resonant configuration). Since the current must be zero at both ends of the antenna (it could not be otherwise) the mechanical ...
- 2,617
2
votes
1
answer
1k
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Why doesn't a transmission line mess up an antenna resonance?
I don't understand why the resonance of an antenna is not affected by the transmission line to the receiver. For example, given a dipole antenna like the following:
The antenna length is carefully ...
- 4,494
1
vote
3
answers
909
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How does the tuner really work in a crystal set?
I would like to know how and why the tuner works in a crystal set radio. I already know all the theory and the "formal definitions" (this creates a resonant circuit which responds to an alternating ...
- 13
0
votes
1
answer
61
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Connecting two antennas to provide signal
Problem:
I am in a room without FM signal. I would like to provide FM signal to the room.
If you have a hole for coaxial cable, which can connect a place with signal and the room, is it possible to ...
- 101