[Lowfer] Still looking for a capacitance dissapation factor test

[Bill Ashlock]

>I connect the scope to the transformer primary and adjust the
> > turns in the transformer so that at resonance the voltage dips to 1/2. I
> > then calculate the what the Rac load on the secondary must be by 
>dividing
> > 180 ohms by the square of the number of turns. For example, if the turns
> > count is 30: 180/900 = 0.2 ohms. The combined Q is the XL of the loop 
>(or
> >Xc  of the capacitance) divided by 0.2.

>How does this loaded Q figure compare to one derived from a measurement of
>the -3dB points (with the same setup)?

Hi Dave,

As far as I can tell they are close but it's really hard to find the -3 db 
points with the Wavetek when the loop Q is running up to 800 (remember this 
is 1700k, not 185k or 137k). It's very easy to tune for the dip in voltage 
that I mention above. I'm finding that I can't trust the normal ways of 
measuring loop current. Even with a descent Tek current probe the loop Q 
falls to considerably less than its actual value because of the insertion 
loss (actually less than 0.1 ohms).

Bill A

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