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Old February 22nd 08, 01:37 PM posted to rec.radio.amateur.antenna
Keith Dysart[_2_] Keith Dysart[_2_] is offline
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First recorded activity by RadioBanter: May 2007
Posts: 492
Default Forward and Reverse Power

On Feb 21, 9:53*pm, Cecil Moore wrote:
Keith Dysart wrote:

Hey Keith, how about this one?

* * * * * * * *Rs * * * * * * Pfor=50w--
* * * * *+----/\/\/-----+----------------------+
* * * * *| * *50 ohm * * * * * *--Pref * * * *|
* * * * *| * * * * * * * * * * * * * * * * * * |
* * * * Vs * * * * * * * * * 45 degrees * * RLoad+j0
* * * 100v RMS * * * * * * * 50 ohm line * * * |
* * * * *| * * * * * * * * * * * * * * * * * * |
* * * * *| * * * * * * * * * * * * * * * * * * |
* * * * *+--------------+----------------------+

The dissipation in the source resistor is:

P(Rs) = 50w + Pref

How can anyone possibly argue that reflected power
is *never* dissipated in the source resistor? :-)
--
73, Cecil *http://www.w5dxp.com


Two Saturdays ago I was on a road trip and used
9 litres/100km. How can anyone argue that the fuel
consumption is never equal to the day of the month?
Numerical coincidences can be much fun.

But you will like the generator below even better.
The power dissipated in the generator resistors is
always equal to 50 + Pref, regardless of the load
and line length, thereby always accounting for Pref.

Pfor=50w--
+--/\/\/---+----------------+-------------------+
| 100 ohm | --Pref |
| | 100 ohm |
| +--/\/\/--+ any length |
| ^ | 50 ohm line any load
Vs Is | |
100v RMS 1A RMS | |
| | | |
+----------+---------+------+-------------------+
The generator output impedance is 50 ohms.
Dissipation in the generator resistors is always
50 Watts plus Pref.
With a shorted or open load, the power dissipation
in the generator is 100 W.

Numerical coincidence as proof that Pref is always
dissipated in the generator. :-)

On a more serious note, how would you analyze this
generator using reflected power and constructive
and destructive interference?

...Keith