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#1
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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 Q500 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 |
#2
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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 Q500 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. |
#3
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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 |
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