Re: Variation in readings of R value
Hi Pete. The inductor is supporting a propagating field. It is both magnetic and electric. You are correct, while the magnetic properties of a core are key to control loss, so are the dielectric
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alan victor
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#33378
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Re: Best NANOVNA Version that displays reactance, not uH & C
You can change the setting in the menu to display R+jX instead of the default R +inductance/capacitance. Roger
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Roger Need
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#33377
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Re: Variation in readings of R value
Alan, How does the loss factor of the dielectric that the coil form is made from impact the magnetic circuit? I have heard others mention this but with no explanation. Thanks, Pete
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WB2UAQ
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#33376
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Best NANOVNA Version that displays reactance, not uH & C
Good evening! I would very much appreciate recommendations on the best version of the NANOVNA that displays reactance values for the markers on the Smith chart, instead of inductance and capacitance.
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Tom AE5I
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#33375
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Re: Variation in readings of R value
Excellent Mike. So that is a Qul of 348. I spilt the difference between 6 and 8 ohms... lets say 7... From the appearance of your coil, that seems reasonable. The material you wound the unit on has a
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alan victor
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#33374
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Re: Variation in readings of R value
OK I had a go at this with my NanoVNA and got the attached result, which if I follow your calculation correctly equates to Rq = 8.05 ohms. Coil64 estimates 5.9 ohms which, given the less than ideal
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Mike
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#33373
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Re: nanoVNA-H net com usb port
Return it and get a refund. Then go to R & L Electronics and purchase a genuine one. Problem solved!!! PS... This is the very best advise ANYBODY can give you!!!
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Dentron
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#33372
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Re: Variation in readings of R value
Alan I found the article from your earlier link and will give it a go, thanks. In the meantime I repeated my measurement with NanoVNA-App calibrated for 6401points and got a slightly lower value of
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Mike
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#33371
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Re: Pickup Coil Construction for Inductor Measuremenfs
I had the thought to get one some time back, and started looking on ebay. It's amazing how many of these units do NOT have any of the coils with them! I know of one guy who took on one of those and
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Roy J. Tellason, Sr.
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#33370
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Re: Variation in readings of R value
Mike, the article is in this file
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G8DQX list
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#33369
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Re: Variation in readings of R value
If difficulty in finding the paper from EDN and the figures, here is a pdf abbreviated and a test case circuit screen capture. If you are careful in fixture construction depending on operating
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alan victor
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#33368
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Re: Pickup Coil Construction for Inductor Measuremenfs
I occasionally see them for sale at hamfests. I have gotten a few that way, but I shouldn't have - I haven't used any yet. Not even the big, (relatively) heavy old U.S. military one. If you look for
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DougVL
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#33367
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nanoVNA-H net com usb port
I am using nanoVNA-H The product was purchased on Ali Express, and I thought it was genuine, but it was fake. First of all, I am a Windows 10-64bit user. What did you do to solve the problem 1.
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brojunes@...
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#33366
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Re: Variation in readings of R value
Thanks Alan I'll have a look at that. -- Mike
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Mike
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#33365
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Re: Variation in readings of R value
Mike 15 ohms is not too far from what a long inductor made with small gauge wire could have. Q of about 143. Pete
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WB2UAQ
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#33364
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Re: Variation in readings of R value
Mike, Scratch that idea about the scales because it doesn't work the same at 4 MHz where the Z should be about +j503 ohms.
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WB2UAQ
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#33363
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Re: Variation in readings of R value
Mike Is the scale of your reactance graph supposed to be in kohms and not just ohms? I think so because at 3 MHz the impedance of the series L-C would be about -j911 ohms. Correct? Pete
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WB2UAQ
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#33362
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Re: Variation in readings of R value
Hi Mike, Please see message # 23812. This documents one approach. Alan
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alan victor
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#33361
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Re: Calibration
What happens when you try to calibrate it? "Can't get it calibrated" isn't very specific. Does the unit fail to respond correctly at some point in the calibration procedure?
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Jim Allyn - N7JA
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#33360
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Re: Variation in readings of R value
Hi Pete, it's an air cored coil with an inductance of around 108uH. I made the measurement with an 18pF COG capacitor in series so the plot is showing the resistance around the resonant frequency of
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Mike
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#33359
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