Buck wrote:
I gathered that from an earlier post, but I think the confusion comes
in the second second, doesn't it? 100 watts of power is generated
from the generator for two seconds. the first second, 100 watts
travels to the antenna and only 100 watts is in the transmission line.
Then for the second second, 100 forward watts is moving towards the
antenna and 50 reflected watts are returning to the transmitter for a
total of 150 watts in the transmission line? Of course, since the
transmitter isn't matched to the antenna, the reflected power is
reflected again for 25 watts being reflected back to the antenna
bringing the power from 100 forward watts to 125 watts (the reason
power meters go up in wattage when SWR rises) thus the antenna
reflects 62.5 watts which adds to the 125 for a total of 187.5 watts
in the transmission line. Sooner or later one will have a meltdown
that will make Chernoble look like a firecracker compared to a
fireworks display. lol

Actually, the forward power levels off at 200 watts during steady-
state. The reflected power levels off at 100 watts. 300 joules of
energy exist that have been sourced but not dissipated in the load.
300 joules are exactly what the forward wave and reflected wave
need to support their existence.

Here's the brainteaser configuration:

100W-SGAT---one second long lossless 50 ohm feedline---291.42 ohm load

The 'SGAT' is a signal generator equipped with a super fast auto-tuner
that re-reflects all the reflected power back toward the load so there
are no losses at the source end. The only losses in the entire system
are in the 291.42 ohm load which, to make the math easier, was chosen
for a power reflection coefficient of 0.5, i.e. half the incident
power is reflected at the load.

I will generate an EXCEL spreadsheet today that will give a second by
second summary of the powers and total energy.

In the meantime, here is a more simplified version of the brainteaser.

100W-SGCL---one second long lossless 50 ohm feedline---291.42 ohm load

The 'SGCL' is a signal generator equipped with a circulator and 50 ohm
resistor. During steady-state, half the generated power is dissipated
in the load and half in the circulator resistor. There are no re-
reflections at the source.

During the 1st second, the source supplies 100 joules into the feedline.
There is no dissipation either in the load or circulator resistor.

During the 2nd second, the source supplies another 100 joules into the
feedline, 50 joules of which are converted to heat in the load and 50
joules of which are reflected from the load as 50 watts of reflected
power. At the end of the 2nd second, the feedline contains 150 joules
of energy.

During the 3rd second, steady-state is reached. Of the 100 watts sourced,
50 watts are dissipated in the load and 50 watts are dissipated in the
circulator resistor. At the end of the 3rd second, the source has
generated 300 joules, 100 of which have made it to the load, and 50 of
which have made it to the circulator resistor.

300-100-50 = 150 joules stored in the feedline.

100 joules are stored in the 100W forward wave. 100 joules/sec = 100W

50 joules are stored in the 50W reflected wave. 50 joules/sec = 50W

This conservation of energy works for any length feedline. If the feedline
were one microsecond long instead of one second long, there would be 150
microjoules stored in the feedline, 100 microjoules in the forward wave
and 50 microjoules in the reflected wave.
--
73, Cecil http://www.qsl.net/w5dxp