On Dec 13, 2024, at 09:22, Jim Lux via groups.io
<jimlux@...> 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.

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 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 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>
Virus-free.www.avg.com <http://virus-free.www.avg.com/>
<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
<#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

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

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

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

<

http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail

Virus-free.www.avg.com <http://virus-free.www.avg.com/>
<

http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail

<#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

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.

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 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" :

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&rsquo;t think the NanoVNA is the way to do this. Not only is the
&ldquo;bottom&rdquo; end of the synthesized source a bit high, but the whole
&ldquo;what&rsquo;s the step size of the PLL&rdquo; thing might bite you.


I&rsquo;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&rsquo;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.