Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [transmission-line]

A transmission line may refer to a cable or assembly that is designed to carry radio frequencies and must consider the wave nature of the signal. Coaxial cable is an example of a transmission line.

It may also refer to high-voltage power transmission lines, used to transfer power from generating stations to consumers.

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Why weights on cables between utility poles?

Yesterday I saw what look like weights hanging from a cable between utility poles. This was in northeast Arizona on Route 60 between Show Low and Springerville. Here is a picture of a whole span: The white blobs are the weights. Here is a…
Olin Lathrop
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Meaning of balanced transmission line?

Simple question, what does it mean to have a transmission line (RS-485 in my case) balanced vs unbalanced?
fred basset
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Transmission lines - justification of "wavelength / 10" (or similar) rule

I have very little background in electronics, but suddenly I need some transmission line theory for a project I am working on. I have heard of various rules of thumb for how long a wire can be before you have to start worrying about its properties…
user3558855
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Microstrip transmission line impedance calculation

I'm attempting to calculate the necessary trace width of a PCB transmission line in order to have a characteristic impedance of 50ohm. However, different online calculators are giving me slightly different results. My PCB substrate is FR408 from…
MattHusz
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Does conductance in the transmission line model represent a physical quantity?

For context, someone asked a question on amateur radio SE which I'm having difficulty completely understanding myself: Why is coax loss logarithmic? I'm not looking for an answer to that, but rather it's made me realize there are some more…
Phil Frost
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How to measure the actual length of a long twisted pair?

Sometimes we might need to know the exact length of the wire pairs inside a cable. One can be interested in calculating voltage drop or some other calculation regarding the exact length. Because the wires inside the cable are twisted, their…
user16307
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What are the two lines for on top of this tower?

I have seen other towers with the same lines.
mateos
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Is the input impedance of an infinitely long line equivalent to the characteristic impedance if the attenuation constant is 0?

My book says that the input impedance of an infinitely long line is equal to the characteristic impedance as long as the attenuation constant is not equal to 0. Is this true? I think it may be an error in the book because the formula for wave…
JobHunter69
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What's the reason for this unusual transmission tower (pylon) design?

I saw this unusual transmission tower (pylon) while cycling recently: This is in the UK. Specifically, it's just off the A6, between Preston and Lancaster. The simple hanging attachments are very common, and the ones with a loop of wire are common…
paj28
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Transmission line

I'm currently testing a design, and using two small wires to connect an oscillator with a frequency counter (both are small circuits I have build). So here is a question, when designing RF and connecting different circuits, when is something to be…
JakobJ
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Finding exact breakpoint location in long wire

How can I find the exact location of breakpoint in my long transmission line? Please help with the methods.
Dharma
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Regarding Transmission line

Is every wire a transmission line or a transmission line has a special manufacturing process? But why during analysis of normal electrical circuits we never consider parameters like characteric impedance, R,G,L,C etc and only considered resistors,…
Enthusiast
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Are waves reflected off a transmission line when they reach the generator dissipate there?

There is a generator with ZG = 50 ohms connected to a transmission line of Z0 = 50 ohms, the length of the line can be any, the load is ZL = 200, this gives a reflection coefficient GammaL = 200-50 / 200 + 50 = 0.6, therefore there is a mismatch and…
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Characteristic impedance behavior with frequency

The characteristic impedance of any transmission line is derived as $$ Z_0= \sqrt{\frac{R+j \omega L}{G+j \omega C}} $$ where R is series resistance per unit length, L is series inductance per unit length, C is shunt capacitance per unit length, and…
dirac16
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instant current in very long transmission line

In reading the definition of impedance matched wiring a question popped into my head that I can’t seem to find the answer to. Assuming a 50 ohm impedance line that is infinity long, then in theory if I attached a voltmeter I am able to see 50 ohm…
attle
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