The question that is foremost in my mind right now is why Itsu isn't getting similar results to mine. His coil, as far as I can tell, is very similar to mine. I can understand why/how a current probe might give different results but when he uses a direct voltage probe connection to the 1 ohm resistor he still isn't getting comparable results. Is my scope simply lying to me? It wouldn't be the first time. One thing I've noticed in Itsu's traces is that the Math trace is mostly all positive, except in that very high frequency trial where he finally did get a COP>1.
However I don't even rely on the math trace of my scope any more, I perform the calculations of input power manually using V p-p x 0.3535 to give Vrms, which usually agrees quite closely with the Period Vrms reported by my scope, and as far as I can tell there is no scope error there. The Rigol's RMS bug has been fixed in the latest-but-one firmware update and no longer causes problems with channel crosstalk or erroneous readings from disconnected channels. Again, the basic peak-to-peak voltage values of the scope traces are accurate as far as I can tell and these form the basis of most of my calculations. There is some uncertainty in my scope's reported phase angles but by "eyeball" and also by calculation they seem to be reasonable if not quite exact all the time.
I also find it hard to believe that the small inductance of my 49.58 ohm metal film resistor stack could be skewing my results enough to give the numerical results I'm seeing. Why is it so easy for me to get the results from calculation, when Itsu can't get comparable results at the same low frequencies that I'm getting, since his coil is quite similar to mine in electrical parameters? Is there some really delicate "sweet spot" of coil construction that I just happened to hit? What then about my solenoid results, where I also found it quite easy to get the "OU" numbers?
I must be doing something wrong over and above any other systematic errors caused by incorrect probing in the original schematic. But what could it be? I can't quite see it all being down to the Rigol's reported numbers, somehow.
My next testing, later on this evening, will be to replace the 49.58 ohm metal-film resistors with a 9.4 ohm non-inductive resistor pair in to-220 package, and to replace the 1 ohm non-inductive CVR with a similar Ohmite noninductive 0.1 ohm value.
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