> <snip>
> I don't think that is right. I did another test with the same setup but this
> time I used only a 1000 ohm resistor for a load and no capacitor.
>
> Transmitter--watt meter--tuner--drake watt meter-- 1000 ohm load resistor.
>
> By adjusting the tuner for zero reflected power on the first watt meter that
> leaves the drake watt meter and a 1000 ohm resistive load that should have
> no reflected power.
>
> With 20 watts indicated on the first watt meter the drake watt meter showed
> about 100 watts forward and about 80 watts reflected. The difference in
> forward and reflected readings is the power delivered to the load. But there
> should be no reactive component in the load in this setup. There should not
> be any reflected power from the load. There should be no "apparent power".
>
> The reading of high forward and high reflected power on the meter has to be
> meter error when not operating at the design impedance.
>
> This brings us back to the question of how do we determine how much
> reflected power we have, if any, when looking at a watt meter?
>
> In this case with the 1000 ohm resistor there should be no reflected power
> in the circuit. This indicates a gross error in the meter reading.
>
> 73
> Gary K4FMX
>
Hi Gary.
The output side of the tuner looking into the resistive load is reactive and is
determined by the line length , velocity factor and frequency.
If you have a reference on Smith Charts, you will see that one can transform an
impedance using a length of transmission line.
One can also cancel the reactive component of an antenna by using the same
technique and change the impedance into a pure resistance.
If the line impedance were 1000 ohms (and the resistor is non-inductive), then
there would be a resistive load at the tuner , all frequencies , all line
lenghts.
If it is any other impedance , then there are standing waves on the line and the
impedance at the tuner revolves around a circle on the Smith Chart known as a
Circle of constant SWR and is determined by the position of the line length to
the tuner. It repeats itself every electrical wavelength and is purely
resistive at two positions only.
Voltage magnitude times Current Magnitude is Apparent power and is composed of
Real Power (Watts)and Reactive Power (VARS) . The real power is Includes the
phase angle between I and V . Reactive is whatever is left.
---
Ron
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