K7ITM wrote:
On Mar 31, 6:23 am, Cecil Moore wrote:
With as little effort as possible, determine Pfor2 and Pref2.

Given: Pfor1 = 100 watts, Pref1 = zero watts
[(Z02-Z01)/(Z02+Z01)]^2 = 0.5

100w---Z01 ohm line---+---Z02 ohm line---unknown load
Pfor1-- Pfor2--
--Pref1 --Pref2


If the lines are lossless, Pfor2=175W, and Pref2 is obvious.

Yes, assume the lines are lossless, but I don't think
that is the correct answer.

And it's a REALLY weird way to state the impedances.

Yes, to get people to think outside the box. Since the
Z0s are unknown, the voltages and currents are also
unknown, yet there exists a solution to the problem.
This is the typical kind of problem that my EE professors
used to give to the classes at Texas A&M to try to get
us to use our gray matter.

How do we KNOW that Pfor1 is 100 watts and Pref1 is zero?

Given.

How do we KNOW that line 1 and line 2 each have UNIFORM impedance?

Given.

Just because someone
measured 100W forward and 0W reflected on line 1 doesn't make it so,

Just because 100 watts forward and zero watts reflected
were measured by an ideal directional wattmeter calibrated
for a characteristic impedance of Z01, doesn't make it so???
Now that *is* an interesting diversion.
--
73, Cecil http://www.w5dxp.com