Keith Dysart wrote:
Now just above, you started with 100W + 100W and ended with
400W. And you wonder why readers think you advocate this
position.

100W + 100W is not all we started with. Somewhere
else is 100W + 100W of destructive interference
that adds up to zero.

This is very much like the equation in Born and Wolf.

Itotal = 4I1 where I1 = I2 = 100 watts/unit-area

Such is the nature of constructive interference. That
you are ignorant of such is noted.

Does this not cause you some discomfort? It clearly
violates conservation of energy.

Absolutely NOT! There is 200 watts of destructive
interference somewhere else. Here is a real-world
example:

---291.4 ohm line---+---1/2WL 50 ohm line---291.4 ohm load
Pfor1=200W-- Pfor2=400W--
--Pref1=0W --Pref2=200W

On the load side of point '+':
P1 = Pfor1(1-rho^2) = 100W
P2 = Pref2(rho^2) = 100W

P1 + P2 + 2*SQRT(P1*P2) = Pfor2 = 400W
(200W of constructive interference)

On the source side of point '+':
P3 = Pfor1(rho^2) = 100W
P4 = Pref2(1-rho^2) = 100W

P3 + P4 - 2*SQRT(P3*P4) = Pref1 = 0W
(200W of destructive interference)
--
73, Cecil http://www.w5dxp.com