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Old May 12th 04, 04:55 AM
Reg Edwards
 
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The input reactance of a shorted length of line is given by -

Inductive Xin = j * Zo * Tangent(Theta)

where Theta is line length in degrees.

For a 1/8-wavelength line Theta = 360/8 = 45 degrees, Tangent(45) = 1.0,
and for Zo = 50 ohms the input inductive reactance is also 50 ohms.

===========================

For an open circuit length of line -

Capacitative Xin = -j * Zo / Tangent(Theta)

So for open-circuit 1/8-wavelength line and Zo = 50 ohms, input reactance is
a capacitative -j50 ohms.

The resistive component of input impedance is very small because line loss
is very small for 1/8 wavelength.
----
Reg, G4FGQ

=====================================

"PDRUNEN" wrote in message
...
Hello Group,

If I have an RG-58 coax and it is shorted at the load end. At the

electrical
1/8 wave lenght what would be the impedance seen at the other end?

I understand that a shorted 1/4 wave length reflects an open, but was
interested in what happens at the 1/8 wave frequency.

Tnx de KJ4UO