Hi Dave,
Ok I'll try both methods and see if it comes up with different answers.
Now is there anywhere a he he he "Video" or a written step by step etc, on how to do the smith chart way?
Joe WB9SBD
toggle quoted message
Show quoted text
On 8/15/2021 11:41 AM, David Eckhardt wrote: Is everything these days a YouTube "presentation". I'm not knocking what
is presented, as the theory is sound and is rather reminiscent of the setup
employed when measuring inductance with a grid dip oscillator, but a bit
more accurate.
Any of the NANOs can measure inductance (and capacitance) directly using
the Smith Chart option and the Cursors. Once calibrated, the inductor is
connected across the source port directly, yes, both center pin and
backshell of the connector. It will be in parallel with that port. Once
configured, the value of the real part and the equivalent reactance of the
complex port (the inductor) can be easily read in the upper left of the
NANO display. The NANOs can also be configured to simply display the
reactance of the complex part directly instead of the equivalent value of
the lumped inductor. Again, just an absolutely wonderful instrument which
compares embarrassingly well to the (expensive) HP/Agilent/Keysite VNAs.
Dave - W?LEV
On Sun, Aug 15, 2021 at 1:59 PM Joe WB9SBD <nss@...> wrote:
I found this video,
It seems like maybe a better way?
Thoughts?
Joe WB9SBD
On 8/15/2021 4:59 AM, Victor Reijs wrote:
I think you need a low frequency to determine the inductance (as say you
know).Say between 10kHz and 200kHz? The log(|Z|) curve in a log(Freq)
should go up in a straight line (NanoVNA Saver can provide this log axis).
All the best,
Victor
Op zo 15 aug. 2021 om 01:29 schreef Bob Albert via groups.io <bob91343=
[email protected]>:
First put an adapter on the SMA connector and set up the calibration. Go
to Smith Chart. Select your frequency range. Short the test leads and
see
how much residual inductance there is. Then connect the unknown. Move
the
marker to whatever frequency you like and it will read out directly.
Bob
On Saturday, August 14, 2021, 02:58:37 PM PDT, Joe WB9SBD <
nss@...>
wrote:
I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a
coil?
Joe WB9SBD
|
Agree.? Measure it directly.? Using the method in the vid gives the capacitance inductance product, but not the individual values.? You still need to know the value of one of them to measure the value of the other.? Maybe the value printed on the capacitor is good, but it has a tolerance and may be off even more than that.? Plus, the test setup is adding stray capacitance and inductance that further obfuscates what you want to measure. No need to go back to the old grid dip days, except perhaps for nostalgia.
Agree on YouTubes too.
toggle quoted message
Show quoted text
On Sunday, August 15, 2021, 10:41:30 AM MDT, David Eckhardt <davearea51a@...> wrote: Is everything these days a YouTube "presentation".? I'm not knocking what is presented, as the theory is sound and is rather reminiscent of the setup employed when measuring inductance with a grid dip oscillator, but a bit more accurate. Any of the NANOs can measure inductance (and capacitance) directly using the Smith Chart option and the Cursors.? Once calibrated, the inductor is connected across the source port directly, yes, both center pin and backshell of the connector.? It will be in parallel with that port.? Once configured, the value of the real part and the equivalent reactance of the complex port (the inductor) can be easily read in the upper left of the NANO display.? The NANOs can also be configured to simply display the reactance of the complex part directly instead of the equivalent value of the lumped inductor.? Again, just an absolutely wonderful instrument which compares embarrassingly well to the (expensive) HP/Agilent/Keysite VNAs. Dave - W?LEV On Sun, Aug 15, 2021 at 1:59 PM Joe WB9SBD <nss@...> wrote: I found this video,
It seems like maybe a better way?
Thoughts?
Joe WB9SBD
On 8/15/2021 4:59 AM, Victor Reijs wrote:
I think you need a low frequency to determine the inductance (as say you
know).Say between 10kHz and 200kHz? The log(|Z|) curve in a log(Freq)
should go up in a straight line (NanoVNA Saver can provide this log axis).
All the best,
Victor
Op zo 15 aug. 2021 om 01:29 schreef Bob Albert via groups.io <bob91343=
[email protected]>:
? First put an adapter on the SMA connector and set up the
calibration.? Go
to Smith Chart.? Select your frequency range.? Short the test leads and
see
how much residual inductance there is.? Then connect the unknown.? Move
the
marker to whatever frequency you like and it will read out directly.
Bob
? ? ? On Saturday, August 14, 2021, 02:58:37 PM PDT, Joe WB9SBD <
nss@...>
wrote:
? I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a
coil?
Joe WB9SBD
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Re: Measuring S11 at input of RF power amplifier - could I calibrate "through" an attenuator?
What about connecting the amplifier to a dummy load thru an antenna tuner. Tune for minimum SWR. Then use the Nano to read the impedance of the tuner/dummy load?
Joe
|
Is everything these days a YouTube "presentation". I'm not knocking what
is presented, as the theory is sound and is rather reminiscent of the setup
employed when measuring inductance with a grid dip oscillator, but a bit
more accurate.
Any of the NANOs can measure inductance (and capacitance) directly using
the Smith Chart option and the Cursors. Once calibrated, the inductor is
connected across the source port directly, yes, both center pin and
backshell of the connector. It will be in parallel with that port. Once
configured, the value of the real part and the equivalent reactance of the
complex port (the inductor) can be easily read in the upper left of the
NANO display. The NANOs can also be configured to simply display the
reactance of the complex part directly instead of the equivalent value of
the lumped inductor. Again, just an absolutely wonderful instrument which
compares embarrassingly well to the (expensive) HP/Agilent/Keysite VNAs.
Dave - W?LEV
toggle quoted message
Show quoted text
On Sun, Aug 15, 2021 at 1:59 PM Joe WB9SBD <nss@...> wrote: I found this video,
It seems like maybe a better way?
Thoughts?
Joe WB9SBD
On 8/15/2021 4:59 AM, Victor Reijs wrote:
I think you need a low frequency to determine the inductance (as say you
know).Say between 10kHz and 200kHz? The log(|Z|) curve in a log(Freq)
should go up in a straight line (NanoVNA Saver can provide this log axis).
All the best,
Victor
Op zo 15 aug. 2021 om 01:29 schreef Bob Albert via groups.io <bob91343=
[email protected]>:
First put an adapter on the SMA connector and set up the
calibration. Go
to Smith Chart. Select your frequency range. Short the test leads and
see
how much residual inductance there is. Then connect the unknown. Move
the
marker to whatever frequency you like and it will read out directly.
Bob
On Saturday, August 14, 2021, 02:58:37 PM PDT, Joe WB9SBD <
nss@...>
wrote:
I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a
coil?
Joe WB9SBD
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Re: Measuring S11 at input of RF power amplifier - could I calibrate "through" an attenuator?
While an interesting measurement, unless the amp is powered, the characteristics of the active device will be way off.
Now when powered (A learning experience from years ago) there will be quite a bit of white noise generated by the active device.? ?This noise added to the actual reflected signal results in Input Return GAIN.? Not loss.? ? The VNA sees the circuit as a reflection amplifier.? Shades of Parametric Amps from the early days of Radio Astronomy.? ? ??
I'm afraid the NanoVNA just isn't the tool for this job.? ? Kent WA5VJB
toggle quoted message
Show quoted text
On Sunday, August 15, 2021, 08:57:36 AM CDT, eyecue_two@... <eyecue_two@...> wrote:
IT would help to know what amp you are looking into with the Nano.? I have been able to check and tune mine with the power off by manually closing the keying circuit
|
I found this video,
It seems like maybe a better way?
Thoughts?
Joe WB9SBD
toggle quoted message
Show quoted text
On 8/15/2021 4:59 AM, Victor Reijs wrote: I think you need a low frequency to determine the inductance (as say you
know).Say between 10kHz and 200kHz? The log(|Z|) curve in a log(Freq)
should go up in a straight line (NanoVNA Saver can provide this log axis).
All the best,
Victor
Op zo 15 aug. 2021 om 01:29 schreef Bob Albert via groups.io <bob91343=
[email protected]>:
First put an adapter on the SMA connector and set up the calibration. Go
to Smith Chart. Select your frequency range. Short the test leads and see
how much residual inductance there is. Then connect the unknown. Move the
marker to whatever frequency you like and it will read out directly.
Bob
On Saturday, August 14, 2021, 02:58:37 PM PDT, Joe WB9SBD <nss@...>
wrote:
I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a
coil?
Joe WB9SBD
|
Re: Measuring S11 at input of RF power amplifier - could I calibrate "through" an attenuator?
IT would help to know what amp you are looking into with the Nano. I have been able to check and tune mine with the power off by manually closing the keying circuit
|
Re: download the calibration from the NanoVNA
But this internal calibrstion format
|
Re: download the calibration from the NanoVNA
Use console data command
data 2
data 3
....
data 6
|
download the calibration from the NanoVNA
Hallo all of you,
Do you know if it is possible to download the calibration files from the
naanoVNA to the NanoVNA Saver? I understand NanoSave Saver can use the
device (NanaVNA) calibration... . I would like to be able to save that
device calibration file from the NanoVNA Saver (which looks not to be
possible it seems...)?
Any help is welcome. Thanks.
All the best,
Victor
|
I think you need a low frequency to determine the inductance (as say you know).Say between 10kHz and 200kHz? The log(|Z|) curve in a log(Freq) should go up in a straight line (NanoVNA Saver can provide this log axis). All the best, Victor Op zo 15 aug. 2021 om 01:29 schreef Bob Albert via groups.io <bob91343= [email protected]>:
First put an adapter on the SMA connector and set up the calibration. Go
to Smith Chart. Select your frequency range. Short the test leads and see
how much residual inductance there is. Then connect the unknown. Move the
marker to whatever frequency you like and it will read out directly.
Bob
On Saturday, August 14, 2021, 02:58:37 PM PDT, Joe WB9SBD <nss@...>
wrote:
I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a
coil?
Joe WB9SBD
|
Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
I remove first message, for download last firmware need use file section /g/nanovna-users/files/Dislord%27s%20Nanovna%20-H%20FirmwareNote: firmware pack contain zip archive for H/H4/V2/V2plus/V2Plus4 devices. For V2 series also for different display size 2.8/3.5 inch need use 320x240, for 4 inch 480x320, all V2 formware build for disabled FPU
|
First put an adapter on the SMA connector and set up the calibration.? Go to Smith Chart.? Select your frequency range.? Short the test leads and see how much residual inductance there is.? Then connect the unknown.? Move the marker to whatever frequency you like and it will read out directly.
Bob
toggle quoted message
Show quoted text
On Saturday, August 14, 2021, 02:58:37 PM PDT, Joe WB9SBD <nss@...> wrote:
I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a
coil?
Joe WB9SBD
|
Re: danger measuring antenna
Dave: That choke also serves another very important function; it will short the plate supply to ground if the anode coupling capacitor should suffer from leakage current or fail short, keeping you from impressing plate voltage onto your antenna and whatever else is attached to the output terminal.
73, Don N2VGU.
|
I have a NanoVNA-H4.
Using this, what is the best accurate way to measure the inductance of a coil?
Joe WB9SBD
|
It does.
*Clyde K. Spencer*
toggle quoted message
Show quoted text
On Sat, Aug 14, 2021 at 5:55 PM Joe WB9SBD <nss@...> wrote: This is just a test to see if this group passes images.
Thank You
Joe WB9SBD
|
This is just a test to see if this group passes images.
Thank You
Joe WB9SBD
|
Re: Measure coax length with Transform, where does the length start?
When you do your calibration, the device includes the cable length as part of the device. It doesn¡¯t matter if you do the calibrations at the vna or at the end of a 20 foot cable, that distance is calibrated out of the equations.
Sent by me
toggle quoted message
Show quoted text
On Aug 14, 2021, at 17:12, Torbj?rn Toreson <torbjorn.toreson@...> wrote:
?Hello,
Measuring coax length has been discussed in several topics. However I have a query. I have calibrated at the end of the short coaxes delivered with the Nano (in my case NanoVNA H4) about 18 cm long and I am using Dislords FW 1.0.64. Nevertheless it seems to me that measuring coax length with the Transform method will include the length of the short coax, so the "measurement plane" seems actually to be at the connection point to the Nano itself. I know about the Marker/Measure in later FW, but I don't know if that FW makes the measurement start at the calibration plane (my guess) or at the Nano, so the same query for that. The question arose when I tested the iteration method to find the VF that I mentioned in another topic, my iteration method gave VF 59 % for a RG58 coax about 2 meters long, if I include the length of the short coax the VF would be 66 % which is more plausible for a RG58.
73/Torbj?rn
|
Measure coax length with Transform, where does the length start?
Hello,
Measuring coax length has been discussed in several topics. However I have a query. I have calibrated at the end of the short coaxes delivered with the Nano (in my case NanoVNA H4) about 18 cm long and I am using Dislords FW 1.0.64. Nevertheless it seems to me that measuring coax length with the Transform method will include the length of the short coax, so the "measurement plane" seems actually to be at the connection point to the Nano itself. I know about the Marker/Measure in later FW, but I don't know if that FW makes the measurement start at the calibration plane (my guess) or at the Nano, so the same query for that. The question arose when I tested the iteration method to find the VF that I mentioned in another topic, my iteration method gave VF 59 % for a RG58 coax about 2 meters long, if I include the length of the short coax the VF would be 66 % which is more plausible for a RG58.
73/Torbj?rn
|
Re: 340 MHz Dipole - Calibration at Transmitter and Antenna Ends of Transmission Line
The coax need not be any specific length, just long enough to make a "good"
measurement (low enough in frequency). Z = SQRT (L/C) applies to any
length, so long as the L and C are measured over the same length
transmission line. When I made a careful measurement of a roughly 28-MHz
"length" of parallel conductor windowline, I did not get the 450-ohm result
as advertised. I got something around 410 to 420 ohms. A online
discussion ensued where several participants brought out the fact that
there is available "windowline" anywhere from 400 ohms through 470 as
common offerings. I then checked DavisRF where I bought it some 9 years
ago. Sure enough, they do sell the "advertised" 470 ohm window but also
other values of impedance as well. I also "exercised" several online
applets which purport to calculate the impedance of parallel conductors
given the appropriate parameters. Of course, I did not measure the
relative dielectric constant of the spacers. I took "their word" for that
parameter. I could have done the measurement at the measurement frequency,
but didn't want to make yet another fixture.
At Phillips Lab where I worked before moving to N. Colorado with HP, we
were required to maintain 0.5 dB consistency between setups (HPPM
instrumentation). That is a monumental task if you've ever been there!!
No Pasternack connectors were allowed in the setups, just expensive
*machined* HP connectors and adaptors. Won't go into details, but once
things were set up the previous evening, no one was permitted to enter the
setup other than to remove our focus target for the video cameras the next
morning. Even a minor move of the coax cables in the setup (generally 7/8
hardline of corragated hardline) would change things.
Personally, I wouldn't be too concerned with your 51.067-ohm result against
50.000-ohms and your disagreement against the published value of pF/foot.
Did you measure the frequency, L, C, and the length of your coax (to
determine pF/foot) to three significant figures which your impedance
shows? What are your error bars on all your measurements? Would you
subject your conclusions to a rigorous analysis using the tools of the
calculus of variations? I'm too old (and wise) for that at this point.
Given my write-up on measuring L and C, I would augment based on additional
posts, to properly establish the 1/8-wavelength frequency for the L and C
measurements. At least that unquestionably pegs the measurement frequency
with a known technique.
Dave - W?LEV
toggle quoted message
Show quoted text
On Sat, Aug 14, 2021 at 7:30 PM Kent AA6P <kawill70@...> wrote: Dave - I'd first like to explain why the Smith Chart method is showing
51.067 ohms for the RG-58A/U in the SimSmith simulation. As you can see in
the attachments of my previous post, no adapters are being used. All we
have is the source, coax, and load (100M ohms or 0 ohms).
If I followed your instructions correctly, the capacitance figures don't
translate directly to the capacitance per foot in the coax. However, that
would not matter if the method is still calculating the characteristic
impedance correctly. The significance of the complex impedance at the two
measurement points is not entirely clear.
I agree that additional measurements would help clarify the actual
hardware being used.
Thanks, Kent
AA6P
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Lou W7HV
Donald S Brant Jr
