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Old August 26th 03, 03:08 PM
W5DXP
 
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Ian White, G3SEK wrote:
There in one sentence is the whole problem with the "power" approach.
For a complete solution including phase conditions, you have to assume a
Z0-match, and even Cecil acknowledges that is only true for "most ham
systems".


But Ian, what we have been arguing about for two years is what happens
to the energy around a *Z0-match point*. Now you admit that, for a Z0-
matched system (which most ham systems are) the power approach yields
a "complete solution including phase conditions". We are making progress.

As Reg says, this is because the power approach throws away the phase
information at the start, and if you want it back again, you have to
make assumptions.


For an energy analysis, you don't need the phase information. Energy,
like SWR, is the same for 50+j50 and 50-j50.

So the problem is not that the "power" approach cannot give a complete
solution, but that it cannot do it for all cases. In other words, it
isn't completely general - and that flaw is fatal.


You don't understand the purpose of a "power" approach. It is not to
solve for the phases. It is to analyze the energy flow. For that purpose,
like SWR, it is not necessary to know the sign of the reactance. I have
specifically said that the power approach does not attempt to replace
conventional approaches. It augments conventional approaches to determine
the details of the energy flow, something the conventional approach sadly
lacks.
--
73, Cecil http://www.qsl.net/w5dxp



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