# Help: line transmission question

Hi
I am trying to calculate impedance in a line transmission but cant seem to figure it out :(
i have so far undertood that it is calculated by zo = R+jwL/G+jwC

The values i have found so far to help me with the task are:
R =100 ohms
L=225 micro henry
C = 9.3 Nano farads
G = 0.01 S

Can anyone get back to me asap with some help as i have got cswk in for today and am REALLY struggling :(

Regards
Dan

## Answers and Replies

I don't follow??

Where are those values in a transmission line? Per metre?

Time and time again people get a poor response because their question is vague.

Hi Dan
use conjugate multiplication!!
multiply (R+jwL) and (G-jwC) in the numerator..(G+jwC) and (G-jwC) in the Dr.
Substitute...w^2 = (1/LC)

yeah i guess its per metre...

Hi
I am trying to calculate impedance in a line transmission but cant seem to figure it out :(
i have so far undertood that it is calculated by zo = R+jwL/G+jwC

The values i have found so far to help me with the task are:
R =100 ohms
L=225 micro henry
C = 9.3 Nano farads
G = 0.01 S

Can anyone get back to me asap with some help as i have got cswk in for today and am REALLY struggling :(

Regards
Dan
You miss the square root!!! Z0=SQRT[(R+jwL)/(G+jwC)]

I don't know how you get the numbers. I think it should be close approx. Make sure you use meter, farad/meter, henry/meter etc. for calculation. I am not 100% sure.