Velocity Factor & Wave Length: What's the Connection?

[edieber]

is the Velocity Factor is a factor to caculate the length wave(gama) or its only connected to the type of the cabe

 

[Integral]

Could you try rephrasing the question? Perhaps there are others on the board who speak your native language who will help you translate.

 

[edieber]

Could you try rephrasing the question? Perhaps there are others on the board who speak your native language who will help you translate.

I just want to know the meaning of Velocity Factor and if it influence the calculation of the length wave?

 

[jcsd]

I just want to know the meaning of Velocity Factor and if it influence the calculation of the length wave?

Your going to have to be a lot clearer and give the context as what you are using is from what I gather the 'velocity factor' is engineering terminlogy referring to the speed of propagation of a signal as a fraction of c, though I could be wrong (and I think you mean wavelength not 'length wave').

 

[edieber]

Your going to have to be a lot clearer and give the context as what you are using is from what I gather the 'velocity factor' is engineering terminlogy referring to the speed of propagation of a signal as a fraction of c, though I could be wrong (and I think you mean wavelength not 'length wave').

do you know if it influence the wavelength?

 

[Tide]

Yes, the relative speed of the source and the detector influences the observed wavelength.

 

[edieber]

Yes, the relative speed of the source and the detector influences the observed wavelength.

what is formula to calculate the wavelength if Velocity Factor is 0.66
and Er=1.2 for example

 

[jcsd]

do you know if it influence the wavelength?

ou have to be clearer 'cos I'm not exactly sure what you're talking about: what exactly are we delaing with? are we dealing with an electrical signal through a wire?

 

[edieber]

ou have to be clearer 'cos I'm not exactly sure what you're talking about: what exactly are we delaing with? are we dealing with an electrical signal through a wire?

yes! electrical signal through a wire

 

[jcsd]

You'd do a lot, lot better to post this on the engineering forum, but:

wavelength = velocity factor*(the speed of light in a vacuum/frequency)

 

[edieber]

You'd do a lot, lot better to post this on the engineering forum, but:

wavelength = velocity factor*(the speed of light in a vacuum/frequency)

where do you take under consideration the Er ?

 

[jcsd]

What is 'Er'?

 

[edieber]

What is 'Er'?

[tex]\epsilon_r[/tex]

dialectrical coefficient

 

[jcsd]

I'll have to say I don't know how you'd go about calcualting or even if you can calculate it from the velcoity factor and the dialectric cooefficient ,though I think your not after the wavelength but the reflection coefficient.

 

[Tide]

$$\lambda_{observed} = \lambda_{source} \sqrt { \frac {1-\frac {v}{c}}{1+\frac {v}{c}}$$

 

[edieber]

$$\lambda_{observed} = \lambda_{source} \sqrt { \frac {1-\frac {v}{c}}{1+\frac {v}{c}}$$

why you don't take under consideration $$\epsilon_r$$
the dialectrical element

 

[Tide]

why you don't take under consideration $$\epsilon_r$$
the dialectrical element

Because I don't fully understand your question. If you are talking about a transmitter and a receiver that are in relative motion with respect to each other then I presume the signal is propagating through empty space or possibly air whose dielectric constant is very close to 1. It doesn't make sense to me that one end of a cable would be moving relative to the other if that's the medium you are talking about.

 

[pervect]

I think he's talking about the velocity of signal transmission along a coaxial cable, or possibly a transmission line.

as in for instance

http://www.nr6ca.org/vf.html

If so, the velocity factor should be approximately c/sqrt(Er), where Er is the permitivity of the dielectric material relative to the permitivitty of free space.

 

[Tide]

I think he's talking about the velocity of signal transmission along a coaxial cable, or possibly a transmission line.

as in for instance

http://www.nr6ca.org/vf.html

If so, the velocity factor should be approximately c/sqrt(Er), where Er is the permitivity of the dielectric material relative to the permitivitty of free space.

Oh, okay! I've never heard it called a "velocity factor."

 

[edieber]

I think he's talking about the velocity of signal transmission along a coaxial cable, or possibly a transmission line.

as in for instance

http://www.nr6ca.org/vf.html

If so, the velocity factor should be approximately c/sqrt(Er), where Er is the permitivity of the dielectric material relative to the permitivitty of free space.

how come if Er=1.24 put it in the formula c/sqrt(Er) it never will be vf=0.666 for example