Re: NANO VNA H4 , Implausible measurement results?
Hi, Brian,
I still have mine with the matching speaker. Mine is an NC-183, not an NC-183D. Like you, I really loved that thing. Even now, the sight of it here brings back good memories.
But I
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Maynard Wright, P. E., W6PAP
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#39982
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Re: NANO VNA H4 , Implausible measurement results?
Maynard, I bought a NC-183 to replace my S-38D in the early 1960s. I just loved that big receiver.
Brian
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Brian Beezley
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#39981
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Re: NANO VNA H4 , Implausible measurement results?
Hi, Ed,
That's true! I remember hearing the phrase "you can work the world with watt and a wet noodle," but I didn't fully understand what was going on at the time.
I did cut an old broadcast
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Maynard Wright, P. E., W6PAP
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#39980
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Re: Measuring Capacitors
I had guessed the DC block above SRF might be useful even when C was not the LF value. Thanks for the insight on R and L, Alan.
Brian
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Brian Beezley
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#39979
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Re: Measuring Capacitors
Well.....here's another one for you: SM inductors. Most of the suppliers
quote Q at 1 MHz.
1) The RF "resistance" (due to skin effect) should be used instead of the
DC resistance.
2) Outside of
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W0LEV
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#39978
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Re: Measuring Capacitors
This is common practice in microwave power amplifiers and and some MMIC designs
as one component brings in two. The R and L for above SRF of the C serves as a DC block
while adding a stabilizing R
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alan victor
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#39977
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Re: Measuring Capacitors
That's what I finally guessed designers must do. Check out the Y21 method plot for capacitance I just posted for a different capacitor. Above the first two resonances, capacitance returns to a
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Brian Beezley
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#39976
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Re: Measuring Capacitors
After looking at more .s2p capacitor files, I've concluded that the file comments refer to the measurement frequency range, not the recommended frequency range for the part.
I've attached
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Brian Beezley
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#39975
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Re: Measuring Capacitors
To elaborate on this a bit. Let’s think about a standard 0602 sized part - that’s 0.06” long or about 1.5 mm. A piece of wire that long has an inductance of about 1.5 nH.
With, say, 33 pF,
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Jim Lux
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#39974
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Re: Measuring Capacitors
Grand! Thank you.
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Steve Withnell
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#39973
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Re: Measuring Capacitors
The max frequency is probably more about where losses get too big.
And they’ll measure for a very wide range. Most design tools can deal with staying away from the SRF, if supplied with the part
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Jim Lux
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#39972
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Re: Jittery , non steady readings
Yes, it is
Zack W9SZ
[email protected]> wrote:
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Zack Widup
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#39971
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Re: Measuring Capacitors
By coincidence, I just added an image showing capacitance and dissipation factor plotted by my S-parameter plotter. It was derived from an .s2p file provided by Kyocera. Scroll to the last
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Brian Beezley
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#39970
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Re: Jittery , non steady readings
Is the measurement frequency stable?
Dave
ZL3FJ
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Dave Brown
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#39969
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Re: Measuring Capacitors
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John Nightingale
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#39968
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Re: Jittery , non steady readings
I have consistently had this problem measuring inductors, capacitors and
resistors. Just recently I measured a silver mica capacitor that was around
3400 pF. I measured at 475 kHz (630 meter amateur
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Zack Widup
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#39967
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Re: Jittery , non steady readings
I live in a quiet neighbourhood; the antenna measures 8 cm from tip to tip. I shall take some measurements at the countryside and report back when I do.
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kellogs
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#39966
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Re: Measuring Capacitors
Too bad it doesn't lead to any practical use. What do you expect me to do with a deadly formula like this?
--
F1AMM
Fran?ois
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Fran?ois
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#39965
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Re: Jittery , non steady readings
I was thinking that such fluctuations seen in NanoVNA were due to
swinging of my multi-band fan dipole in the wind! That would change the
relative nearness of elements to each other and nearby
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Jon
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#39964
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Re: Jittery , non steady readings
Or to put it simply, the VNA contains a highly specialized radio receiver.
"W0LEV via groups.io" <davearea51a@...> wrote:
--
73
-Jim
NU0C
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Jim Shorney
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#39963
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