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Old March 29th 07, 02:47 PM posted to rec.radio.amateur.antenna
Keith Dysart Keith Dysart is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 124
Default Revisiting the Power Explanation

On Mar 29, 7:00 am, "Keith Dysart" wrote:
Good day Dan,

I offer you the same challenge as Cecil, find the error in my
analysis and then compute the correct amount of re-reflection.


Since it can be quite difficult to locate errors in analysises,
I'll offer a simpler challenge to you and Cecil.

For the example I proposed, using the approach of your choice,
compute the magnitude of the first re-reflected signal to reach
the load.

Recall the line is 31 wavelengths long so the signal reaches
the load 31 cycles after the generator is turned on. There is
a reflection which reaches the generator 31 cycles later and
any re-reflection will reach the load after a further 31 cycles.

So you need to compute the magnitude of the reflection which
reaches the load after 93 cycles. This would be the first ghost.

You need to show your work. Handwaving -25dB will not be considered
as answering the question.

....Keith

PS. If you prefer, you may use a slightly different example for
which computation may be easier:
- the line is 1 second long
- the generator creates a 450 V step function at time 0
What is the magnitude of the re-reflection that reaches the load
after 3 seconds?

PPS. The answer to the two problems will be the same.