what about sweeping with a soundcard?? it should be possible to use line out and line in (or mic in) and use a soundcard like the nanovna
(just ab idea from a dumb nut)
sg9bfc sigi

Am 13.12.2024 18:33 schrieb "ww6x via groups.io" :

You could (in theory) put the DUT between two mixers and a shared
oscillator to heterodyne the passband up into a more useful range for the
VNA. (Please don't consider this a serious suggestion, since unwinding all
the sidebands would be a nightmare. And wouldn't solve a PLL stepsize
issue.)

--
ww6x

On Fri, Dec 13, 2024, at 9:22 AM, Jim Lux via groups.io wrote:

I don’t think the NanoVNA is the way to do this. Not only is the
“bottom” end of the synthesized source a bit high, but the whole
“what’s the step size of the PLL” thing might bite you.


I’d look for a cheap USB controlled audio frequency source and a USB AC
voltmeter, and then write a small amount of software to sweep the
frequency and record the voltages. Almost any digital multi meter
would work. As would almost any USB oscilloscope.

It’s kind of more of a pain, but you could probably use a USB audio
interface and playback sine waves of varying frequencies, and record
the responses. Calibration is trickier too.

On Dec 13, 2024, at 04:18, Ken Morrow via groups.io

wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer. Any thoughts or suggestions
would be very much appreciated.

Thank you,
Ken M.

On 16 Dec 2024, at 11:34, Mark Jordan via groups.io <enkitec@...> wrote:


Already done:

https://artalabs.hr/

73, Mark Jordan PY3SS


On 16-Dec-24 10:25, Siegfried Jackstien via groups.io <http://groups.io/> wrote:

what about sweeping with a soundcard?? it should be possible to use line out and line in (or mic in) and use a soundcard like the nanovna
(just ab idea from a dumb nut)
sg9bfc sigi

Am 13.12.2024 18:33 schrieb "ww6x via groups.io" <ww6x@...>:

You could (in theory) put the DUT between two mixers and a shared
oscillator to heterodyne the passband up into a more useful range for the
VNA. (Please don't consider this a serious suggestion, since unwinding all
the sidebands would be a nightmare. And wouldn't solve a PLL stepsize
issue.)

--
ww6x

On Fri, Dec 13, 2024, at 9:22 AM, Jim Lux via groups.io wrote:

I don’t think the NanoVNA is the way to do this. Not only is the
“bottom” end of the synthesized source a bit high, but the whole
“what’s the step size of the PLL” thing might bite you.


I’d look for a cheap USB controlled audio frequency source and a USB AC
voltmeter, and then write a small amount of software to sweep the
frequency and record the voltages. Almost any digital multi meter
would work. As would almost any USB oscilloscope.

It’s kind of more of a pain, but you could probably use a USB audio
interface and playback sine waves of varying frequencies, and record
the responses. Calibration is trickier too.

On Dec 13, 2024, at 04:18, Ken Morrow via groups.io

<ken.morrow586@...> wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer. Any thoughts or suggestions
would be very much appreciated.

Thank you,
Ken M.

what about sweeping with a soundcard?? it should be possible to use line out and line in (or mic in) and use a soundcard like the nanovna
(just ab idea from a dumb nut)
sg9bfc sigi

Am 13.12.2024 18:33 schrieb "ww6x via groups.io" <ww6x@...>:

You could (in theory) put the DUT between two mixers and a shared
oscillator to heterodyne the passband up into a more useful range for the
VNA. (Please don't consider this a serious suggestion, since unwinding all
the sidebands would be a nightmare. And wouldn't solve a PLL stepsize
issue.)

--
ww6x

On Fri, Dec 13, 2024, at 9:22 AM, Jim Lux via groups.io wrote:

I don’t think the NanoVNA is the way to do this. Not only is the
“bottom” end of the synthesized source a bit high, but the whole
“what’s the step size of the PLL” thing might bite you.


I’d look for a cheap USB controlled audio frequency source and a USB AC
voltmeter, and then write a small amount of software to sweep the
frequency and record the voltages.  Almost any digital multi meter
would work.   As would almost any USB oscilloscope.

It’s kind of more of a pain, but you could probably use a USB audio
interface and playback sine waves of varying frequencies, and record
the responses.  Calibration is trickier too.

On Dec 13, 2024, at 04:18, Ken Morrow via groups.io

<ken.morrow586@...> wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer.  Any thoughts or suggestions
would be very much appreciated.

Thank you,
Ken M.

On Dec 16, 2024, at 05:25, Siegfried Jackstien via groups.io <siegfried.jackstien@...> wrote:

what about sweeping with a soundcard?? it should be possible to use line out and line in (or mic in) and use a soundcard like the nanovna
(just ab idea from a dumb nut)
sg9bfc sigi

Am 13.12.2024 18:33 schrieb "ww6x via groups.io" <ww6x@...>:

You could (in theory) put the DUT between two mixers and a shared
oscillator to heterodyne the passband up into a more useful range for the
VNA. (Please don't consider this a serious suggestion, since unwinding all
the sidebands would be a nightmare. And wouldn't solve a PLL stepsize
issue.)

--
ww6x

On Fri, Dec 13, 2024, at 9:22 AM, Jim Lux via groups.io wrote:
I don’t think the NanoVNA is the way to do this. Not only is the
“bottom” end of the synthesized source a bit high, but the whole
“what’s the step size of the PLL” thing might bite you.


I’d look for a cheap USB controlled audio frequency source and a USB AC
voltmeter, and then write a small amount of software to sweep the
frequency and record the voltages. Almost any digital multi meter
would work. As would almost any USB oscilloscope.

It’s kind of more of a pain, but you could probably use a USB audio
interface and playback sine waves of varying frequencies, and record
the responses. Calibration is trickier too.

On Dec 13, 2024, at 04:18, Ken Morrow via groups.io

<ken.morrow586@...> wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer. Any thoughts or suggestions
would be very much appreciated.

Thank you,
Ken M.

You could (in theory) put the DUT between two mixers and a shared
oscillator to heterodyne the passband up into a more useful range for the
VNA. (Please don't consider this a serious suggestion, since unwinding all
the sidebands would be a nightmare. And wouldn't solve a PLL stepsize
issue.)

--
ww6x

On Fri, Dec 13, 2024, at 9:22 AM, Jim Lux via groups.io wrote:

I don’t think the NanoVNA is the way to do this. Not only is the
“bottom” end of the synthesized source a bit high, but the whole
“what’s the step size of the PLL” thing might bite you.


I’d look for a cheap USB controlled audio frequency source and a USB AC
voltmeter, and then write a small amount of software to sweep the
frequency and record the voltages.  Almost any digital multi meter
would work.   As would almost any USB oscilloscope.

It’s kind of more of a pain, but you could probably use a USB audio
interface and playback sine waves of varying frequencies, and record
the responses.  Calibration is trickier too.

On Dec 13, 2024, at 04:18, Ken Morrow via groups.io

<ken.morrow586@...> wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer.  Any thoughts or suggestions
would be very much appreciated.

Thank you,
Ken M.

Yes, my first "knee-jerk" reaction would have been an audio oscillator and
an o'scope. But the noise gen. and SA will give better results in a single
plot on the screen.

I have run across online audio vector network analyzers using the stereo
inputs to higher end sound cards. But they aren't cheap, either, and I
haven't found a freebie. Audio SA's? Yes, there are dozens of those
online supported by a PC.

Dave - WØLEV

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On Fri, Dec 13, 2024 at 8:12 PM Patricio A. Greco via groups.io
<patricio_greco@...> wrote:

Dave: I understand. A nanovna is not a good idea for AF, note the
frequency steps of internal generator, its impossible to use it. May you
use an audio oscillator and scope. Depends on your available equipment.

Ing. Patricio A. Greco
Laboratorio de Calibración ISO 17025 AREA: RF/MW
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
www.servicios-electronicos.com.ar

On 13 Dec 2024, at 16:22, W0LEV via groups.io <davearea51a=

gmail.com@groups.io> wrote:

Cheap? Not on my retirement income! Nominally $ 1.5k.

I looked it up on both epay and "refurbished".

Dave - WØLEV

<

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On Fri, Dec 13, 2024 at 6:40 PM Patricio A. Greco via groups.io <

http://groups.io/>

<patricio_greco@... <mailto:patricio_greco@...>>

wrote:

You can usa an HP8903A audio analyzer… is cheap and works very good. You
can sweep up to 100KHz

Ing. Patricio A. Greco
Laboratorio de Calibración ISO 17025 AREA: RF/MW
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
www.servicios-electronicos.com.ar

On 9 Dec 2024, at 20:04, Ken Morrow via groups.io <ken.morrow586=

gmail.com@groups.io> wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer. Any thoughts or

suggestions

would be very much appreciated.

Thank you,
Ken M.

--

*Dave - WØLEV*


--
Dave - WØLEV

On 13 Dec 2024, at 16:22, W0LEV via groups.io <davearea51a@...> wrote:

Cheap? Not on my retirement income! Nominally $ 1.5k.

I looked it up on both epay and "refurbished".

Dave - WØLEV

<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, Dec 13, 2024 at 6:40 PM Patricio A. Greco via groups.io <http://groups.io/>
<patricio_greco@... <mailto:patricio_greco@...>> wrote:

You can usa an HP8903A audio analyzer… is cheap and works very good. You
can sweep up to 100KHz

Ing. Patricio A. Greco
Laboratorio de Calibración ISO 17025 AREA: RF/MW
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T: +5411-4455-2557
F: +5411-4032-0072
www.servicios-electronicos.com.ar

On 9 Dec 2024, at 20:04, Ken Morrow via groups.io <ken.morrow586=

gmail.com@groups.io> wrote:

I have a question about measuring filters below the low end of any

Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the

Nanovna? I am looking for a way to measure some low pass filters I built
from 0 to ~20KHz (audio range) without costing a ton of money. I do not
have access to a Frequency Response Analyzer. Any thoughts or suggestions
would be very much appreciated.

Thank you,
Ken M.

--

*Dave - WØLEV*


--
Dave - WØLEV

On 13 Dec 2024, at 16:06, Brian Beezley via groups.io <k6sti@...> wrote:

The calculated inductance value includes self-capacitance. Some people call this effective inductance, but I just call it inductance since that's what you would measure with an instrument. Internally I calculate low-frequency inductance and self-capacitance and then combine them. Q depends on wire and lead resistance, skin depth, the proximity effect of nearby coil turns, and coil form loss. I model form permittivity as constant but form loss tangent varies with frequency. You can use custom dielectrics if you want. Incidentally, a coil generally has maximum Q at about 45% of SRF. For best performance you don't want to operate too far below self-resonance.

I think the value of the program is to find optimal coil dimensions. For many coil applications there's no need to maximize Q. But when its important, such as for antenna loading coils or traps, the optimizer can save a lot of experimentation. Then build the coil and check it with a VNA.

I took your coil and optimized the number of turns and coil length. The result is shown below. I suspect you may be using metric units. Click on " for mm.

Brian





<opt.png>

On 9 Dec 2024, at 20:04, Ken Morrow via groups.io <ken.morrow586@...> wrote:

I have a question about measuring filters below the low end of any Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the Nanovna? I am looking for a way to measure some low pass filters I built from 0 to ~20KHz (audio range) without costing a ton of money. I do not have access to a Frequency Response Analyzer. Any thoughts or suggestions would be very much appreciated.
Thank you,
Ken M.

On 13 Dec 2024, at 14:06, Brian Beezley via groups.io <k6sti@...> wrote:

On Fri, Dec 13, 2024 at 08:44 AM, Patricio A. Greco wrote:

A Q factor with an error of 10% is very good for the most applications

Patricio, this calculator may interest you for inductor design. Its Q accuracy is within a few percent on average for test coils measured with an HP 4342A Q meter. Worst case Q error is < 10%. It has an optimizer for maximizing Q. It can also optimize a coil for minimum loss in a trap. Much to my surprise, this does not occur at maximum coil Q.

http://ham-radio.com/k6sti/coil.htm

Optimizing wideband antenna models with coils or traps:

http://ham-radio.com/k6sti/wbc.htm

Brian

I don’t think the NanoVNA is the way to do this. Not only is the
“bottom” end of the synthesized source a bit high, but the whole
“what’s the step size of the PLL” thing might bite you.


I’d look for a cheap USB controlled audio frequency source and a USB AC
voltmeter, and then write a small amount of software to sweep the
frequency and record the voltages. Almost any digital multi meter
would work. As would almost any USB oscilloscope.

It’s kind of more of a pain, but you could probably use a USB audio
interface and playback sine waves of varying frequencies, and record
the responses. Calibration is trickier too.

On Dec 13, 2024, at 04:18, Ken Morrow via groups.io <ken.morrow586@...> wrote:

I have a question about measuring filters below the low end of any Nanovna.

Is it possible to extrapolate both S21 and S11 down to DC on the Nanovna? I am looking for a way to measure some low pass filters I built from 0 to ~20KHz (audio range) without costing a ton of money. I do not have access to a Frequency Response Analyzer. Any thoughts or suggestions would be very much appreciated.
Thank you,
Ken M.