On Dec 7, 12:37 pm, Cecil Moore wrote:
Keith Dysart wrote:
On Dec 6, 9:48 pm, Cecil Moore wrote:
So are we agreed that a 43.4 degree stub terminated in
0-j567 ohms impedance is electrically 1/4WL, i.e. 90
degrees long?

There are many ways to get the 0 input impedance:
(1)- 43.4 degrees of 600 ohm line terminated in a lumped 0-j567 impedance
(assuming I recall the problem corrrectly and you did the math
correctly)
(2)- 43.4 degrees of 600 ohm line followed by 46.6 degrees of 600 ohm
line, open at the end
(3)- 43.4 degrees of 600 ohm line followed by 10 degrees (IIRC) of 100
ohm line, open at the end
(4)- a short
(5)- 180 degrees of any impedance line shorted at the end
- and many, many more

If you calculate the complex rho and calculate the phase
shift provided by a -j567 impedance, you will agree with
my statement above.

Are you claiming that all of these are electrically 1/4WL ?

Of course not!!!! I numbered your examples above. Examples
1-3 are electrically 1/4WL long. Example 4 is 0 WL long.
Example 5 is 1/2WL long.

All my remarks apply only to stubs and antennas that are
electrically 1/4WL long. My remarks do NOT apply to any
stub or antenna that is not electrically 1/4WL long. An
ideal open stub that is 3/4WL long has the same impedance
as a 1/4WL stub but is it obviously not 1/4WL long.

Your original claim was that 43.4 degrees of 600 ohm
line terminated with 0-j567 was electricall 90 degrees long.
You made no reference to how the 0-j567 was obtained.

You have said that 1, 2 and 3 from above are electically
90 degrees.

How about:
(6) 43.4 degrees of 600 ohm line, 180 degrees of arbitrary
line terminated in a lump of 0-j567. This is just another
way of placing 0-j567 at the end of the 43.4 degrees of
600 ohm line.

And (5), if we use 600 ohm line is also 43.4 degrees of
600 ohm line terminated with 0-j567, this being obtained
with 136.6 degrees of 600 ohm line that is short
circuited.

So while I can accept your statement , "My remarks do
NOT apply to any stub or antenna that is not electrically
1/4WL long.", I am having great difficulty coming up for
a rule so that I will know when your remarks apply.

Can you provide a rule for discerning when a stub or
antenna is electrically 1/4WL long?

....Keith