I'm making high Q measurements. My Q meter only goes to 625, so I have added a ~ 2.15 ohm resistor in series with the coil. I'm testing a reference inductor with and without the resistor to find the value of the resistor. The resistor value comes out as follows.
500kHz 2.19 ohms 600kHz 2.20 ohms 700kHz 2.23 ohms 800kHz 2.26 ohms 900kHz 2.28 ohms 1000kHz 2.29 ohms 1100kHz 2.30 ohms 1200kHz 2.30 ohms 1300kHz 2.44 ohms 1400kHz 2.45 ohms 1500kHz 2.52 ohms 1600kHz 2.64 ohmsI understand that the resistor mounting will also have an effect, so here is a picture of the banana plug, pcb, and two parallel 4.3 ohm carbon composition resistors. When I measure without the resistor the adapter assembly is removed and the inductor wire is connected directly under the knurled nut.
OK, I know there will be capacitance and inductance effecting the R, also my pcb maybe causing some of this difference. I don't know what I'm seeing, is it L or C? My tuning cap change is only 0.1pf different but it is both way and often I see no difference at all.
I note the transition of the resistance is not smooth, I'm sure that is my measurements, is there a way to smooth this or, is this discontinuous transition possible. I suspect it should fit a smooth curve.
Thanks for your input, Mikek