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NanoVNASaver also uses heuristics for NanoVNA V2plus4:


this might be worth including in the SimSmith utility as well

thanks, DiSlord. Once I changed bandwidth to 4kHz on NanoVNA H4 then SimSmith connects/interacts with the device.
I tried both 101/401 data points and both settings are okay.
Still no luck with the NanoVNA V2plus4 though

I checked with NanoVNASaver and indeed timeout handling is made dependent on bandwidth and #data points:


and:

50 ohm PL259 O239 connectors are readily available. Agree that if the discontinuity is very short compared to a 1/4 wave it make little/no difference. Going from a 50 ohms, through a 30 ohm PL259, and then back into a 50 ohms, the reflection from 50 into 30 is opposite and equal to that from 30 into 50. If the distance between them is very short compared to 1/4 wavelength, they essentially cancel. A PL259 it's maybe a cm or two compared to 250 cm for a 1/4 wavelength at 10m.

You can look inside HF amplifiers, tuners and other HF equipment and see RF being conducted around inside with simple wires, not transmission lines. That works because the lengths are short compared the the wavelengths involved.

I can connect SimSmith vs my NanoVNA H4

SimSmith use old data exchange format, and not allow get data if set low bandwidth setting on Nano (need more big timeout)

Look at W2AEW YouTube channel I think he did a video on this.

73
Fred KB4QZH

On 7/16/21 12:16 AM, James Balagtas wrote:

Hi guys
Wonder if you can acctually cut an exact 1/2 wave coax for a given freq without getting VF and math usong nano VNA. It woukd be very useful when making 4:1 balun with better accuracy rather than estimating with math.

Very easy - cal the vna, hook up your coax, look at the *phase* of S11.? Cut until the phase is zero degrees at your frequency of interest.? Your cable is a multiple of half wavelengths.

180 degrees phase shift on the way out, reflection from the open (which does not flip the phase, like a short does), 180 degree phase shift on the way back, so the net is zero degrees.

The magnitude of S11 is twice the cable loss.


If you want a 1/4 wave stub, go for 180 degrees. 90 degrees on the way out, reflect, 90 degrees on the way back.

I also need it for duplexer pigtails.
Ive been searching in youtube if soneone ever did a video.
Thanks more power
DW3JBX
James

Forgot one important note. Trim the coax stub until the dip is at the
desired frequency.
*Clyde K. Spencer*

You can try this process.
[image: image.png]


*Clyde K. Spencer*

On Wed, Jul 14, 2021 at 03:04 PM, ward harriman wrote:

This utility can be used to connect to, calibrate, initiate measurements,
write touchstone files, and import them for further analysis.

I have used NanoVNASaver and SimSmith earlier this year to construct the output matching network of a DIY BS170 small signal amplifier.
This required constant switching between NanoVNASaver (to measure) and SimSmith (to analyze). Doing all this from within SimSmith will
be a big time-saver and streamline the process. I even noticed that one can apparently define the value of the calibration load to
a value other than 50 ohm.

That being said: I tried to get the latest SimSmith running under both Windows 10 Pro and Ubuntu 20 LTS. On both OSes I have no issue
connecting to the NanoVNA (both -H4 with latest Dislord firmware and newest V2plus4 w/ stock firmware) with NanoVNASaver but I'm unable
to connect with SimSmith. I can see and select the serial port from the drop down list but then it always after a small time reports 'Connection Lost'.
On Ubuntu I see a Java exception 'serialStuff.SerialException: Serial Port Timeout' in serialStuff.Utils.getDataLines(Utils.java:150) which
seems to originate from nanoVNA.Dialog.probePort(Dialog.java:493). The selected serial port remains with a red background in SimSmith.

Is this an issue with EOL character differences between Windows/Linux vs. Mac? Did others have more luck?
I really want this to work ...

Uwe.

Hi guys
Wonder if you can acctually cut an exact 1/2 wave coax for a given freq without getting VF and math usong nano VNA. It woukd be very useful when making 4:1 balun with better accuracy rather than estimating with math.
I also need it for duplexer pigtails.
Ive been searching in youtube if soneone ever did a video.
Thanks more power
DW3JBX
James

It looks like the file in that One Drive folder has been deleted. It was good when I downloaded it yesterday. I have a copy of it on my hard-drive but it's almost 3GB. Too big to email and I don't have enough room on my OneDrive account to move it there where I could share it.

Hopefully, Barry will see this and reload it where everyone can get to it again.
--
*Don - W3DRM*

I had the same thing happen

On Thu, Jul 15, 2021 at 8:55 PM Josh Kuperman <josh.kuperman@...>
wrote:

On Wed, Jul 14, 2021 at 09:49 PM, W3DRM - Don wrote:

I started watching the video this morning and made it through the very
basic but good explanation of smith charts; then I ran some errands and
started watching again and after 5 minutes the video vanished.

Hi David, I had a similar problem and used the SMA to PL-259 and PL-259 to
SMA adapters. I guess you know that the PL-259 connectors are no where near
a 50 ohm environment (around 30 ohms I think). But at 30MHz this should not
be a problem. Pete

On Thu, Jul 15, 2021 at 8:49 PM David Kozinn, K2DBK <dkozinn@...>
wrote:

This is a timely thread as I just received my -F this week. My HF antennas
all have PL-259 connectors. To connect them to the NanoVNA, I already have
SO-239 to SMA Male (like these
<>). I don't have PL-259 open,
short, and loads (though obviously open & short would be trivial to build)
and I'm wondering for HF frequencies (up to 30MHz), would the calibration
done on the port (using the supplied calibration connectors) be acceptable,
or I should I get an SMA female to PL-259 (like this
<

)

and calibrate at the female SMA?

The final result (during calibration) would look like: SMA
open/short/load->SMA female to PL-259->SO-239 to SMA male->S11 on NanoVNA.

Is this overkill, and would that last adapter invalidate any
calibration when it's removed to plug in the actual antenna?

73,
David, K2DBK
k2dbk.com
twitter: @k2dbk


On Thu, Jul 15, 2021 at 3:39 PM ward harriman <ward.harriman@...>
wrote:

I am of the practice of ALWAYS doing a calibration. This comes from many
scars of debugging ‘unexpected’ results which, ultimately, turned out to

be

calibration problems.

Calibration just doesn’t take that long. I consider it insurance against
my own forgetfulness.

Ward

On 7/15/21 5:48 PM, David Kozinn, K2DBK wrote:

This is a timely thread as I just received my -F this week. My HF antennas
all have PL-259 connectors. To connect them to the NanoVNA, I already have
SO-239 to SMA Male (like these
<>). I don't have PL-259 open,
short, and loads (though obviously open & short would be trivial to build)
and I'm wondering for HF frequencies (up to 30MHz), would the calibration
done on the port (using the supplied calibration connectors) be acceptable,
or I should I get an SMA female to PL-259 (like this
<>)
and calibrate at the female SMA?

It's all about "length vs wavelength" so.. a cm or so of adapter against 10m wavelength? Not going to make a big difference at HF (1cm is 0.3 deg of phase at 30MHz)

I use a SMA to SO-239 pigtail about 12" long - good strain relief, no worry about snapping the SMA off the board.

It's not that hard to build some cal standards - Open is easy, nothing :) - Short isn't too tough (shove some copper foil tape into an PL-259, or just solder a short between center pin and outside.? 50 ohm load is likewise easy for HF - non-inductive resistor on a PL-259.

The final result (during calibration) would look like: SMA
open/short/load->SMA female to PL-259->SO-239 to SMA male->S11 on NanoVNA.

Is this overkill, and would that last adapter invalidate any
calibration when it's removed to plug in the actual antenna?

73,
David, K2DBK
k2dbk.com
twitter: @k2dbk


On Thu, Jul 15, 2021 at 3:39 PM ward harriman <ward.harriman@...>
wrote:

I am of the practice of ALWAYS doing a calibration. This comes from many
scars of debugging ‘unexpected’ results which, ultimately, turned out to be
calibration problems.

Calibration just doesn’t take that long. I consider it insurance against
my own forgetfulness.

Ward

I apologize, I meant to say it WAS A HARD CHOICE, not that it wasn’t.

I don’t want to come across poorly.

Thanks for understanding

Ward
ae6ty

On Wed, Jul 14, 2021 at 09:49 PM, W3DRM - Don wrote:

I started watching the video this morning and made it through the very basic but good explanation of smith charts; then I ran some errands and started watching again and after 5 minutes the video vanished.

This is a timely thread as I just received my -F this week. My HF antennas
all have PL-259 connectors. To connect them to the NanoVNA, I already have
SO-239 to SMA Male (like these
<>). I don't have PL-259 open,
short, and loads (though obviously open & short would be trivial to build)
and I'm wondering for HF frequencies (up to 30MHz), would the calibration
done on the port (using the supplied calibration connectors) be acceptable,
or I should I get an SMA female to PL-259 (like this
<>)
and calibrate at the female SMA?

The final result (during calibration) would look like: SMA
open/short/load->SMA female to PL-259->SO-239 to SMA male->S11 on NanoVNA.

Is this overkill, and would that last adapter invalidate any
calibration when it's removed to plug in the actual antenna?

73,
David, K2DBK
k2dbk.com
twitter: @k2dbk


On Thu, Jul 15, 2021 at 3:39 PM ward harriman <ward.harriman@...>
wrote:

I am of the practice of ALWAYS doing a calibration. This comes from many
scars of debugging ‘unexpected’ results which, ultimately, turned out to be
calibration problems.

Calibration just doesn’t take that long. I consider it insurance against
my own forgetfulness.

Ward

Lay off the griping and make the measurement in a 50-ohm system. With
that, you'll learn how better to use a VNA.

Grumpy: Dave - W?LEV

On Thu, Jul 15, 2021 at 4:02 PM Dr. David Kirkby, Kirkby Microwave Ltd <
drkirkby@...> wrote:

On Wed, 14 Jul 2021 at 20:02, WB2UAQ <pschuch@...> wrote:

This is a long thread so this might have been mentioned already. I bet I
am way out of line. Sorry.

Why can't the measurement be made with a 50 ohm network analyzer?

It can be, and that's the most sensible thing to do.

Dave

--
*Dave - W?LEV*
*Just Let Darwin Work*

On Wed, 14 Jul 2021 at 20:02, WB2UAQ <pschuch@...> wrote:

This is a long thread so this might have been mentioned already. I bet I
am way out of line. Sorry.

Why can't the measurement be made with a 50 ohm network analyzer?

It can be, and that's the most sensible thing to do.

Dave

You can absolutely measure at one impedance and display at another. Most comprehensive Smith chart programs allow the user to ‘change the center of the chart’ to any impedance.

You can just import an impedance file and then set the center to (say) 75 ohms and be done.