"Owen Duffy" wrote in message
...
Breaking out of the previous thread to explore the "power explanation" in
a steady state situation:

The scenario for discussion is a transmitter connected to a half wave of
600 ohm lossless transmission line connected to an antenna with a
feedpoint impedance of 70+j0.

The transmitter is rated for 100W output, 100W is developed in the 70 ohm
load, the VSWR on the transmission line is 8.6, the "forward power"
(meaning Vf^2/Zo) on the transmission line is 267W, the "reflected
power" (meaning Vr^2/Zo) on the transmission line is 167W, the DC input
power to the transmitter is 200W.

The questions a

Is there any internal inconsistency in the scenario characterisation, if
so, identify / explain?


i think the best answer is... it depends.
it depends on what the radio looks like to the reflected power.
for instance, if the tx output network included a circulator and dummy load,
then the reflected power would be lost and there would be no way to get 100w
into the load.
however, because of the conditions given it would appear you have assumed a
perfect re-reflection of the reflected power at the tx end of the line so
everything balances perfectly.


What is the heat dissipated in the transmitter (and why)?

200w dc in, 100w rf into load, lossless line, sounds like 100w dissipated in
the tx to me.


What part of the "reflected power" of 167W is dissipated in the
transmitter (and why)?

none. it is all re-reflected back toward the load.