[Lowfer] Still looking for a capacitance dissapation factor test

[Ed Phillips]

Dave Brown wrote:
> 
> Bill
> 
>  Yes- I'm finding that measuring Q when it's higher than about 500 or so is
> quite challenging- and I've had similar issues with a Tek probe as well. I
> guess as long as one can characterise all the test gear correctly it's
> possible to compensate readings but it seems to be bordering on the
> uincertainty principle sometimes!
> 
> 73
> Dave
> ZL3FJ

	I've had good luck estimating RF resistance by a substitution method. 
For low-Z (L/C) circuits connect them in parallel resonant circuit and
feed them through a resistance at least as large as their parallel loss
resistance.  Measure voltage at resonance, remove the circuit, and
substitute resistors until the voltage is the same.  (You have to be a
little careful about the generator waveform.)  For high-Z circuits
connect them in series resonance and do the same thing, although with a
much lower series resistance in the generator lead.  The method seems to
work pretty well for loading coils and Tesla coil primaries (low-Z) and
secondaries (high-Z).

Ed