RadioBanter - View Single Post - Re-Normalizing the Smith Chart (Changing the SWR into thesame...

August 28th 03, 12:11 PM

W5DXP wrote:

wrote:
This emphasis on NET seems to be the place where the difficulties
begin. An (ideal) voltmeter placed at a voltage minima on the line
indicates a voltage of 0 volts. You appear to be saying that
despite this indication of 0, there is actually voltage present.

There are actually two voltages present of equal amplitude and
opposite phase. Their phasor sum is zero volts.

- how do I determine what these voltages actually are?

|Vfwd| = Sqrt(Pfwd*Z0) |Vref| = Sqrt(Pref*Z0)

If the voltmeter reads zero, these two voltages are equal in magnitude
and opposite in phase.

So when I use my voltmeter to measure a voltage, I actually have
two voltages present which sum to the reading.

When I do this on a D-cell, what are these two voltages?
When I read 0 on a piece of NMD-90, what are these two voltages?
When I read 0 on D-cell, what are these two voltages?
When I read 120 volts on a power outlet, what are these two voltages?
For each of the above, explain how you decided.

It would seem that this belief will lead to some serious decidability
issues.

And don't ever trust your voltmeter again.

....Keith