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Hell forum,

please your help,

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I am building my QMX+ V3.

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On page 30 of the assembly instructions, there is a table were L518 is 268nH with 23 turns on the pink T37-0 core.?

This one turn less than L516 (435nH) with the same core.?

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Measuring with the nanoVNA, L518 with 23 inductance is about 100nH higher. To reach the 268nH, I have to reduce multiple turns.

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So here goes my question:

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Should I keep undoing turns until I reach the 268nH or should I ignore the nano VNA and keep the 23 turns?

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The same applies to L517, were the number of turns seams high for the target 316nH.

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The previous coils were very close to the target inductance.

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Thank you for your help,

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Luis

CU2IJ

Hi Luis,

You should use the number of turns indicated, and ignore the nanoVNA results. The inductance value is from a theoretical model, the number of turns is what was found to work best in practice.

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Quoting Hans from the assembly guide:

"Note that the Inductance column shows the theoretical inductance modeled. This is only then a guide for experimentation during the
development phase, the practical result differs from the model inevitably. Therefore it is recommended to not get too fancy, don’t try to measure using an LC-meter etc., just count turns, evenly space them around the core, and let’s see how it goes."

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Stan KC7XE

Hi Stan

I will do as you say.

Thank you very much,

Luis CU2IJ

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