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On Sun, May 29, 2022 at 12:50 AM, tuckvk3cca wrote:

Great thanks. Any body has a spreadsheet then to convert S21 gain and phase
data into impedances?

There are two methods to Convert S21 to Z. The series method is used for "high impedances" and the "shunt method" for low impedances. These are built into the latest firmware for H/H4 and in NanoVNA Saver and NanoVNA app. You need a very good test jig for S21 series or the phase angle will have errors and the impedance measured will be way off. Also the H/H4 do not have precise 50 ohm source and load impedance so you get errors from that as well.

But to directly answer your question here is is a link to a Web site with a spreadsheet. The link is in the last paragraph.


Here is a link to another one....
/g/nanovna-users/message/17807

Roger

I posted an updated version of this doc, which is the same content as the older doc, but because it contains more operational information, I renamed it to a user manual. I thought that I had sent a message to the group when it posted, but I didn't see the message.

We now have a newer firmware version, so I'll see if I can find the time to update...

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

The following files and folders have been deleted from the Files area of the [email protected] group.

* /user manual and menu maps/nVNA-H4 v4.3_MS, firmware 1.1, Menu Items & Descriptions 0110..zip

*By:* Rich NE1EE <TheDustyKey@...>



---

The following files and folders have been uploaded to the Files area of the [email protected] group.

* /user manual and menu maps/nVNA-H4 v4.3_MS, firmware 1.1, User Manual 0100.zip ( /g/nanovna-users/files/user%20manual%20and%20menu%20maps/nVNA-H4%20v4.3_MS,%20firmware%201.1,%20User%20Manual%200100.zip )

*By:* Rich NE1EE <TheDustyKey@...>

*Description:*
nVNA-H4 v4.3_MS, firmware 1.1, User Manual 0100 latest version. includes more operational notes. Word and PDF.

Yes, disconnect all power for a while. The ultimate and first try to fix ANY and EVERY computer that I know of. Even my wife has learned that.

Dave K8WPE

David J. Wilcox’s iPad

Thanks, Roger. I'll give that a try.
Perry

On Sat, May 28, 2022 at 1:40 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Fri, May 27, 2022 at 04:15 AM, Perry Westberry wrote:

Yes, I adjusted the whip. No transmitter use. Can it be fixed?
Perry

One thing you might try is to charge the unit overnight. Then open the
case and then disconnect the battery by taking the connector off the
board. Wait a minute or so and then re-connect the battery. This may
help if the CPU chip is in some unknown state....

Roger

On 2022-05-29 00:50:-0700, you wrote:

Great thanks. Any body has a spreadsheet then to convert S21 gain and phase data into impedances?

You might find this useful...I did it with real data from my -H4 and my EF 40 m wire. You can make a copy of this spreadsheet so that you have a backup.
Then open it,
and start a new spreadsheet.
Select Data > From Text
In the File Selector mask drop box, select all files *.*
Browse to your s1p / s2p files
import one
start at line ? depending on what line data starts in your snp file.
should read right in.
----- either
copy your data in cols to this spreadsheet, noting that it has a col inserted where freq is converted to MHz
if your data is shorter (fewer rows) delete the extra rows
-----or
copy the formulas from this spreadsheet to your spreadsheet, paying attention to changing cols

It's just some thing I tossed together to look at some data but
S11, SWR, Linear, SWR:Linear, Z, |Z|, Q
are all good calculations

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

Great thanks. Any body has a spreadsheet then to convert S21 gain and phase data into impedances?

On Sat, May 28, 2022 at 05:48 AM, Brian Donaldson wrote:

I have been playing around with some 75Ω cable about 5' in length. I am
using, for training purposes, both the Transform/Linear method and the
Measurement/Cable method. I find that each method gives a different result,
usually by .x meters. Kind of like "he who has two clocks does not know what
time it is". Neither is exact to my known physical measurement, which I
expected because not even the most expensive VNA can measure exactly what a
physical measurement can. Heck, even physical measurement can be off.

So in your humble opinion, which method do you use most, and have you found it
accurate enough (for government work - LOL)?

I find the TDR method to be quite accurate. NanoVNA Saver works quite well.

However all these methods need an accurate Velocity Factor (VF) input. The VF of an actual cable will often differ by +/- a few percent from the manufacturers published VF spec for two reasons:

1. Manufacturer tolerance is not that tight and there are variations between batches and year to year production runs.
2. VF varies with frequency. It increase with frequency until it plateaus.

Some cable length algorithms work at lower HF frequencies and others work at high frequencies. So to get an accurate estimate you need to measure a known length of cable and adjust the VF input until you get the correct answer. Then use that VF to measure a unknown length of the same type of cable.

On Sat, May 28, 2022 at 02:21 PM, Brian Donaldson wrote:

Nice chart, Roger. What is the source? If I were to guess, I would say from a
professional VNA unit.

I can't remember where I got it. It might have been in a previous post in this group.

Roger

On Sat, May 28, 2022 at 03:20 PM, tuckvk3cca wrote:

Does anyone know to improve the plots? They look faint and grainy. I tried
averaging over several sweeps to no avail. They are barely visible on screen.
Also how do I export the data file to Excel from Saver? The format is not
compatible.

Just click "Display Settings" and then select "Show Lines" Then select your line width and dot size. See attached screenshot.

To import into Excel just create a .s1p or .s2p Touchstone file. Import it into Excel as a CSV type text file but use space as the field delimiter instead of a comma.

Roger

On 5/28/22 3:20 PM, tuckvk3cca wrote:

Does anyone know to improve the plots? They look faint and grainy. I tried averaging over several sweeps to no avail. They are barely visible on screen.
Also how do I export the data file to Excel from Saver? The format is not compatible.

Save it as a s1p or s2p file.? While not precisely Excel, they are close enough - use convert data to columns



Here's a sample

# HZ S RI R 50
50000 0.3278822061648298 0.0003739103343315503
248313 0.328285326287687 0.0015557506945497147
446626 0.32822092682405846 0.0029309634344108363
644939 0.32844895504782573 0.004060610839382848
843252 0.3285898865263095 0.0053706571213506605
1041565 0.32863535107606096 0.006618052059875603
1239878 0.32875097837556466 0.007896690878789381

Make sure that "Show Lines" is checked in the Display Settings.

Does anyone know to improve the plots? They look faint and grainy. I tried averaging over several sweeps to no avail. They are barely visible on screen.
Also how do I export the data file to Excel from Saver? The format is not compatible.

Nice chart, Roger. What is the source? If I were to guess, I would say from a professional VNA unit.

Thanks
Brian D
KF6BL

On Fri, May 27, 2022 at 04:15 AM, Perry Westberry wrote:

Yes, I adjusted the whip. No transmitter use. Can it be fixed?
Perry

One thing you might try is to charge the unit overnight. Then open the case and then disconnect the battery by taking the connector off the board. Wait a minute or so and then re-connect the battery. This may help if the CPU chip is in some unknown state....

Roger

On Sat, May 28, 2022 at 09:02 AM, Brian Donaldson wrote:

I also notice that by changing the STOP frequency, the value of length
changes. Minor but still there are changes. Do you have a recommend STOP
frequency, or within a percentage of what one would think the length to be?

I use Dr. Gudinuf's method. Saver says I have a fault at 4 meters out. Ahah, the remote switch isnt working right.If Saver says the fault is at 46 feet, A hah, the squirrel has been nibbling again.If the fault is at 1 meter, hey duufus. PLug the cable back in.Works for me.

I see in the image that K=70%. That seems to be the default when doing a reset of the unit. I find myself doing the test with the known length cable and getting a wrong value. Then I realize that the VF was not set. Once that was done and doing the test again, I get a closer value.

I also notice that by changing the STOP frequency, the value of length changes. Minor but still there are changes. Do you have a recommend STOP frequency, or within a percentage of what one would think the length to be?

Thanks
Brian D
KF6BL

I keep both of my NanoVNA (-H and -H4) up to date just to keep them up to date. I don't think using an older version for basic functions will be an issue. However, These updates, obviously, are to correct bugs found and add new features as you already know. If you check the depository where the new versions are, you should find release notes, hopefully. I will check the depository often to ensure I have the latest.

I personally use Hugen79 version. Don't know why, just do.


Looks like DiSLord has a new version just released a few hours ago (5/28/2022 12:55 UTC)


Brian D
KF6BL

Transform method use steps (distance between points) depending from points count / start / stop / velocity
Example on H4 401 points, start 1M stop 1.5G step = 54,7mm
So you can`t get result between points

Cable->Measure use phase change point (180 degree rotation) so more close to real results, but also can give small errors depend from vrong velocity factor and small points in measure point (use big range)
Most good results method give if you select stop freq little bigger then smith rotate on 180 degree (as on screenshot)
Also need use correct velocity factor for cable