On Jun 14, 12:25*am, K7ITM wrote:
Cecil Moore wrote:
On Jun 13, 1:55*pm, K7ITM wrote:
*It doesn't make any sense to me to put a shorted
section of line in series with another line, so my confusion starts.

Tom, I didn't know initially that the example was in "Reflections
III". A series stub can be used instead of a loading coil on a wire
antenna. I had never seen a series stub used in such a manner on a
transmission line and that's why I was confused. I'm assuming that the
center conductor is broken and one side is connected to the inner
conductor and one side is connected to the braid on a stub, but I am
not sure that is correct. There's got to be a less complicated example
that we can use.
--
73, Cecil, w5dxp.com

Ah, OK. *Now I understand what Walt meant... *Though it's possible to
use a series stub on a transmission line, as you say, it's not all
that common in practice. *I suppose that's why my mind wasn't going
there. *Mea culpa. *Perhaps now I can go back and look at Walt's
original question and make more sense out of it.

When a series stub is used in an antenna (as in a quarter-wave stub
coupling colinear half-waves), King points out that coupling from the
antenna fields to the wires in the stub, when the stub is an open-wire
line perpendicular to the axis of the half-waves, is an important
factor in how the stub operates to establish in-phase currents on the
adjacent half-waves... *I see you made a comment about antenna
currents on the stub in John Smith's example, too.

Cheers,
Tom


I'm sorry to have misled you in bringing up the series stub problem.
What I'm really concerned about is the reflection coefficient at the
output of the tank circuit of the RF power amp. Being non-dissipative
it cannot absorb the reflected power, so it must re-reflect it.
Therefore, my position is that its reflection coefficient rho = 1.0,
My critics say that a rho = 1.0 cannot be established when the virtual
short is caused by wave interference. However, if Best's Eq 8 is
valid, then why does it yield an incorrect answer when I plug in rho s
= 1, and rho a = 0.5, which gives 2 as the answer, instead of the
correct 1.1547 as the correct answer.

Now that I've narrowed the problem down, what do you believe is the
answer? Your answer will determine whether I need to delete the
pertinent paragraph from Chapter 25 in Reflections 3, in which I have
declared Best's Eq 8 invalid.

Walt

Walt