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Old March 1st 07, 06:59 PM posted to rec.radio.amateur.antenna
Jim Kelley Jim Kelley is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 666
Default tuner - feedline - antenna question ?

Cecil Moore wrote:

So the question is: With a forward RF energy flow of 200
joules/sec and a reverse RF energy flow of 100 joules/sec,
would you agree that there is 300 joules of energy existing
in a lossless one-second long transmission line? i.e. exactly
the amount of energy required to support the forward RF
energy wave and the reflected RF energy wave.


I think it depends on how long the energy has been flowing. But in the
steady state it's rather like posing this question: With a forward
speed of 200 knots, and with a headwind speed 100 knots, would you
agree that the apparent airspeed of the aircraft is 300 knots?

Or if the above transmission line is one microsecond long,
that 300 microjoules of energy exists in the line, i.e.
exactly the amount of energy required to support the
forward RF energy wave and the reflected RF energy wave.


Or even if the forward energy is 200 microjoules/sec, reverse of 100
microjoules/sec through a 1 second transmission line.

It's kind of a boring problem though. Personally, I think it's more
interesting and enlightening to consider what goes on prior to steady
state.

73, ac6xg