Qonfusion Heath QM-1

[exray]

I just got hold of a Heath Q-meter and am taking it out for a test drive
this afternoon. This is my first date with a Q-meter and I have a lot of
beginner questions but I'll cut to the chase.

First off it would appear that I'm in need of the calibration gizmo
which I understand can be duplicated fairly easily??? Is there anything
critical about the particular values used with this unit as long as they
are in the ballpark and known to be accurate?

I tried measuring the Q of a few coils and can indeed tell the
differences but even on the worst ones I'm peaking off the scale, ie
Q>500 which I know cannot be correct. Knowing intimately the coils I'm
using I could probably guess the calibration into place within Q=50-100
and that might be adequate for me since the precise "number" isn't my
concern inasmuch as being able to do some coil quality experiments and
evaluations.

Next, I can't quite figure out how I'm supposed to be able to evaluate a
capacitor or a complete LC circuit for Q. Maybe this isn't possible with
this rig? Or is it mathematically dependent on the existing internal
components of the rig?

I'll continue reading the manual over and over and maybe it will sink in
but in the meantime if anyone has some user tips I'd appreciate the
assistance.

TIA,
Bill M

[WA3IYC]

In article >, exray
> writes:

>I just got hold of a Heath Q-meter and am taking it out for a test drive
>this afternoon. This is my first date with a Q-meter and I have a lot of
>beginner questions but I'll cut to the chase.

Do you have the manual?
>
>First off it would appear that I'm in need of the calibration gizmo
>which I understand can be duplicated fairly easily??? Is there anything
>critical about the particular values used with this unit as long as they
>are in the ballpark and known to be accurate?

The one I have is a 250 uH coil of known Q, L and C. Seems you need a
calibrated Q meter to make a standard.
>
>I tried measuring the Q of a few coils and can indeed tell the
>differences but even on the worst ones I'm peaking off the scale, ie
>Q>500 which I know cannot be correct. Knowing intimately the coils I'm
>using I could probably guess the calibration into place within Q=50-100
>and that might be adequate for me since the precise "number" isn't my
>concern inasmuch as being able to do some coil quality experiments and
>evaluations.

How are you using the meter? The standard procedure is:

Connect 'unknown' coil rto L terminals
Set the mode switch to "CAL"
Set the oscillator band switch to the correct band (see chart on top of meter)
Set the oscillator dial to correct frequency (see chart on top of meter)
Adjust level control to red "X1" line on meter
Switch to "Q"
Adjust meter zero control so meter reads zero.
Adjust LC dial to peak
Read L from dial
Read Q from meter

>
>Next, I can't quite figure out how I'm supposed to be able to evaluate a
>capacitor or a complete LC circuit for Q. Maybe this isn't possible with
>this rig? Or is it mathematically dependent on the existing internal
>components of the rig?

The Q of most capacitors is so high that the tuned circuit Q is determined by
the coil, so if you know coil Q you know the LC Q.

73 de Jim, N2EY

>
>I'll continue reading the manual over and over and maybe it will sink in
>but in the meantime if anyone has some user tips I'd appreciate the
>assistance.
>

[exray]

WA3IYC wrote:

> The Q of most capacitors is so high that the tuned circuit Q is determined by
> the coil, so if you know coil Q you know the LC Q.
>
> 73 de Jim, N2EY

Hmmm, maybe thats the key.

Thanks,
Bill