"Richard Clark" wrote in message
...
On Tue, 14 Oct 2003 20:32:33 -0400, "Tarmo Tammaru"
wrote:
Hi Tam,

Simulations conform to nature, they do not enforce their own rules and
try to mimic someone's notion of "what should be."


No, I built an actual circuit, using perfect components.

If it does not care about coax, this kind of response is an implicit
statement of its being "too hard to manage" so-forget-about-it
approach to changing the problem to suit the answer. In other words,
a model of what? Nothing closer to the original than the oft-quoted
humor of "What is the definition of an elephant? A mouse built to
government specification!"

If you want, I will send you a PDF of the schematic.


And so I return to the statement I objected to:
source impedance does not affect SWR.
which is shown no where to have been attempted, and is shown nowhere
to have been proven. What SWR? Where?

I measured the SWR at the point Cecil proposed. I don't recall him
specifying a transmission line either.



I note the total absence of technical answers to these specific
questions with proofs of unrelated doodling offered instead.

You want equations, OK.
For a meter balanced at 50 Ohms, we have
1) VF= V + 50I
2) VR=V - 50I

3) To keep this simple, let the load be resistive, and equal to R. Now, I =
V/R.

4) Let's define a G=(VP + VR)/(VP - VR).

Plugging 3 into 1 and 2, and then 4, we get

G= [V + (50V/R) + V - (50V/R)]/ [V + (50V/R) - (V- (50V/R)]

G= 2V/[100(V/R)]

5) G=R/50

But 5 is precisely the definition of SWR. Therefore G==SWR. Your Bird
wattmeter does exactly this same thing.

The condescension of
A simulation of a circuit is better than the "bench".
is absurd, especially when that same simulation fails to confirm bench
experience. I would challenge you to offer the testimony of any
single (credible) author of a simulator to stand by this profundity.

I hate to tell you this, but all complicated designs have been proven in by
simulations for years. Nobody builds a Pentium CPU before they make a chip.
They simulate it.

I note this last effort of yours is one of several iterations - which
simulation was the most perfect? The first or the last? Who is to
know? How is it to be known? Simulation did not describe to you what
you had to change in the simulation to achieve Nirvana. None of your
rationale for change emanated from the data, it sprang from the
experience of someone's bench providing superior results. If this
exercise is so much better, it should have taken only one pass to
accomplish. The negation of that is found in the failed attempts.

In analog simulations there is a tradeoff between accuracy, and how long it
takes. Also, I pointed out that I added opamps to the model so I would not
be loading down the line with 10K resistors.

Thus the assertion of:
A simulation of a circuit is better than the "bench".
has been shown to be absurd through successive failures by the author
of that statement.

Just for an example, I can make the source impedance anything I want. Do
that on your bench.



As I have offered before, there is humor to be found in the disconnect
and this *******ization by Cecil reigns supreme in examples. But to
its credit, it keeps me amused and offers considerable fodder for the
mythical lurker to observe where the logical landmines are (or in
counting the field's litter of amputees attempting pirouettes). ;-)

You have been talking to the Easter Bunny again.
Tam/WB2TT

73's
Richard Clark, KB7QHC