Reg, let me guess: you dug that Smith Chart out after all huh? he he he

Btw I had a Power Quality engineer that I was discussing ground line
impedances with remind me that the same 1/4 wave phenomenon can happen in
runs of ground and bonding too. The same radial or parallel or "web" of
connections alleviates that risk with lightning grounding as it does with RF
grounding.

Jack

"Reg Edwards" wrote in message
...
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