NanoVna measuring Q of inductor

Thread Starter

Zeeus

Joined Apr 17, 2019
615
Wish someone will assist

Measuring the Q.. Xl/r . Also, the nanoVna has Q function

But my coils all give low Q.. Less than 70 and can not understand why.. The coils are from kitsandparts

Have used wire gauge 24 and 26.. still can't get high Q at 7Mhz...not even high from 1Mhz to daylight

What can do?

Thanks

IMG_3755.JPG
 

DickCappels

Joined Aug 21, 2008
7,441
Along with the useful information posted above, for the highest possible use many small diameter separately insulated wires in parallel instead of solid wire. This reduces the eddy current losses within the copper.
 

ericgibbs

Joined Jan 29, 2010
12,927
hi Z,
Please post your actual calculations, your numbers look incorrect.?
E
Also what is the inductors internal capacitance.?
 
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bertus

Joined Apr 5, 2008
21,364
Hello,

In the posted PDF, the Q of the T68-2 is given on page 14 in the lower graph.
On page 16 the Q of the T68-6 is given.

Bertus
 

Thread Starter

Zeeus

Joined Apr 17, 2019
615
hi Z,
Please post your actual calculations, your numbers look incorrect.?
E
Also what is the inductors internal capacitance.?
The calculation is right E..The nanoVna also has a Q function.

Didn't check the capacitance... now, will use the graph to check things out

Although i know someone that had a Q of about 160 using T68-6 at 14 Mhz... Mine didn't work
 

DickCappels

Joined Aug 21, 2008
7,441
If you were able to double the frequency without changing anything you would also double your Q, except we know that there is more than just resistance and inductance at work here.
 

Thread Starter

Zeeus

Joined Apr 17, 2019
615
If you were able to double the frequency without changing anything you would also double your Q, except we know that there is more than just resistance and inductance at work here.
lol...oh really? the resistance also increases with frequency but at a slower rate

The nanoVna also has a Q function.. Same reading with calculation Xl/r
 

ericgibbs

Joined Jan 29, 2010
12,927
hi Z,
If you are measuring the inductors laid flat on that what appears to a copper clad PCB, which is used as a ground connection , try moving the inductor away from the copper surface, then retest.


E
 

Thread Starter

Zeeus

Joined Apr 17, 2019
615
hi Z,
If you are measuring the inductors laid flat on that what appears to a copper clad PCB, which is used as a ground connection , try moving the inductor away from the copper surface, then retest.


E
No...can't do that... I even tried without the copper clad..same thing

From the smith chart, it has no capacitance

T68- 6...even from 1Mhz to 10Mhz... The Q is not above 75

Someone please solve problem for TS please

Thanks
but i think, problem lies in your response on ground
 
Last edited:
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