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Old April 4th 06, 12:21 AM posted to rec.radio.amateur.antenna
Tom Donaly
 
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Default Coils and Transmission Lines.

Cecil Moore wrote:

Tom Donaly wrote:

If it's a solution to the wave equation it's o.k., Cecil, but
Hecht is still not using the case where there is a phase difference
between the two waves.



Yes, he is, Tom. The phase *disappears* when you add the two
traveling waves. That you don't recognize that fact of physics
is the source of your misconception. The forward and reflected
wave phasors are rotating in opposite directions at the same
angular velocity. That makes their sum a constant phase value
for half the cycle and the opposite constant phase value for
the other half of the cycle.

I and Richard Harrison have already explained that a number of
times quoting Kraus and Terman.

Here are a number of problems. I(f) is forward current and
I(r) is reflected current. Please everybody, perform the
following phasor additions where I(f)+I(r) is the *standing
wave current*:

I(f) I(r) I(f)+I(r)

1 amp at 0 deg 1 amp at 0 deg _________________

1 amp at -30 deg 1 amp at +30 deg _________________

1 amp at -60 deg 1 amp at +60 deg _________________

1 amp at -90 deg 1 amp at +90 deg _________________

1 amp at -120 deg 1 amp at +120 deg _________________

1 amp at -150 deg 1 amp at +150 deg _________________

1 amp at -180 deg 1 amp at +180 deg _________________

If you guys will take pen to paper and fill in those blanks
you will uncover the misconception that has haunted this
newsgroup for many weeks. If you need help with the math,
feel free to ask for help.


Cecil, if you don't put any phase information in your
original formula it won't be there when you say the
same thing some other way. But if you
do put it in there, then it has to affect both formulas.
If it disappears, you've done something wrong. If you and
Harrison can't figure out how to extract phase information
from a standing wave you should return your diplomas to
wherever you got them from.
73,
Tom Donaly, KA6RUH
(P.S. Let me give you a hint: first you have to find
out what phase means in a standing wave on a transmission
line. You probably already think you know, though, so I
don't expect you to bother much about it.)