"Dr. Slick" wrote in message
om...
As Reg points out about the "normal" equation:
"Dear Dr Slick, it's very easy.
Take a real, long telephone line with Zo = 300 - j250 ohms at 1000 Hz.
(then use ZL=10+j250)
Magnitude of Reflection Coefficient of the load, ZL, relative to line
impedance
= ( ZL - Zo ) / ( ZL + Zo ) = 1.865 which exceeds unity,
and has an angle of -59.9 degrees.
The resulting standing waves may also be calculated.
Are you happy now ?"
---
Reg, G4FGQ
Well, I was certainly NOT happy at this revelation, and researched
it until i understood why the normal equation could incorrectly give
a R.C.1 for a passive network (impossible).
According to Adler, Chu, and Fano, "Electromagnetic Energy Transmission and
Radiatin", John Wiley, 1960, (60-10305),
when they talk about lossy lines, and say that Zo is complex in the general
case, they come up with a maximum value for the reflection coefficient of (1
+ SQRT(2)). Eq 5.14b. Remember, it is a lossy line; so, the reflected
voltage gets smaller as you move away from the load. Somebody might want to
check this out, in case I misunderstood something. BTW, the three authors
were all MIT profs.
Tam/WB2TT
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