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My suggestion is to remove the screen-side cover plate and see if the error phenomenon still exists.
The touch screen is particularly sensitive anywhere there is tension or pressure on the surface.
See mobile phones, mostly the side is grasped by the cover plate, it is not pressed anywhere.
All further operations should then be performed. If the fault persists, an electrical fault can be found.

73, Gyula HA3HZ

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*** nothing is permanent only change ( ) ***

On Thu, May 28, 2020 at 04:34 AM, <david.hostetler@...> wrote:

The high impedance output of this balun is center tapped and the center tap is
grounded back to the input SMA (unless you cut the small trace on the back of
the PCB). When you connect one side of the output to the coax shield going to
the VNA, you short the winding!

Hello David and Roger,
This was the solution. Thank you very much for the hint.

I have the schematic of the balun, but I did not consider the R1 jumper.
II cut the R1 jumper on the lower side of the PCB and calibrated from 50 KHz to 100 MHz.

Now it works as expected, see NooElelc_Balun_9-1_S21_Loss.png.
And the reference from NooElect: balun_one_nine_insertion_loss_comparison_to_70mhz.png
And the setup: RF_Balun_1-9_S11_DSC08237.jpg

So, it is proved, that with a 400 Ohm resistor and a SMA plug you can measure the *Insertion Loss*.

73, Rudi DL5FA

David had a good suggestion on cutting the trace on that NanoVNA balun. I have done that on the ones I own. Here is a circuit drawing of the balun and a photo showing how to cut the track.

Roger

The high impedance output of this balun is center tapped and the center tap is grounded back to the input SMA (unless you cut the small trace on the back of the PCB). When you connect one side of the output to the coax shield going to the VNA, you short the winding!

On Wed, May 27, 2020 at 01:11 PM, <reuterr@...> wrote:

The problem arised when I exchanged this 50 Ohm resistor with a 50 cm RG-315
cable,
connected to the CH1 port of the nanoVNA.
The calibration with that 50 cm RG-316 cable was made before.
So, how can I improve the situation?

Calibrate at the end of the 50cm of cable! USe a small SMT resistor
49.9 ohm 1% works well enough or you can get exact 50 ohm in 1%
SMT.

Short and open are easy.

Did this kind of stuff for measuring antennas feed point Z (non connector) into
the ghz region.

Allison



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No direct email, it goes to bit bucket due address harvesting in groups.IO

Have similar issues with my new H4. The touch screen interface is inconsistent. Sometimes pressing a menu action works with the correct option highlighted. Other times not either with the wrong button selected or nothing happens at all. I have calibrated the LCD.
Simon
ZL2BRG

Have similar issues with my new H4. The touch screen interface is
inconsistent. Sometimes pressing a menu action works with the correct
option highlighted. Other times not. I have calibrated the LCD.
Simon
ZL2BRG

If the touch screen still fails to work after recalibration, the touch screen may be damaged and you can contact your dealer for replacement.

Possible Need run touch screen calibrate

Push leveler button
Push right while not select CONFIG menu
Push leveler button
Push left or right to select TOUCH CAL
Push leveler button

On screen use stylus tap on top left corner
Then on bottom right corner

Check touch screen work, run Touch test (drag on screen and see line)
If ok select SAVE

Rudi,

Here is a suggestion

- Try the test again by putting the 50 ohm load at the end of the cable instead of connecting it to CH1. Now you just have the coaxial cable connected with the same load on the end. Do you get similar S11 results for the NooElec when you put the 50 ohm load on the SMA connector?

- Connect the 50 cm cable from CH0 to CH1 and then use NanoVNA Saver to measure R+jX at the input to the cable. Are you close to 50 + j0 ohms? My results on a NanoVNA (2.8" ver 3.3) using 10 cm of RG-316 below.

Roger

I have the -H model, HW ver. 3.4, SN 20011259 build Dec 26, 2019. I have had this for about 2 weeks and it had been working nicely. Purchased from GigaParts.

1. The unit turns on and the identification screen appears.

2,Touching the screen brings up the menu bar on the right..

3. Touching the menu bar brings up the user screen with the grid. The menu remains on.

4. Touching the menu bar to selection an action turns the menu off. Nothing is selected.

5. The unit is not functioning.

Any suggestions please?

Paul, W8SBH

I ordered the updated, 3 button "F" model on February 29, 2020. I was delivered yesterday, May 26th, by the USPS. Tracking consistently showed that the parcel had been shipped some time in early March but that it was stuck in either outgoing customs or incoming customs in the U.S. The little training kit that I ordered at the same time was delivered in a timely manner and I have had it for almost 3 months now.

Hang in there, things will work out!

KM5XK

Thanks, Herb! Crystals are one of my interests.

I tried running it with Python2.x and 3.x, it apparently requires Python3.7. Haven't tried actually measuring a crystal with it yet, but this works, anyway:



jim@jim-P55A-UD3P:~/crystalweb$ python3.7 ./crystalweb.py --help
usage: crystalweb.py [-h] [--fixture] [--loss] [--theta THETA] [--stray STRAY]
[--repeat REPEAT] [--load LOAD] [--title TITLE]
[--device DEVICE] [--start START] [--stop STOP]
[--capture]

optional arguments:
-h, --help show this help message and exit
--fixture measure test fixture stray capacitance (default: False)
--loss measure test fixture loss (default: False)
--theta THETA phase angle for measuring bandwidth (default: 45)
--stray STRAY test fixture stray capacitance in pF, affects Co (default:
None)
--repeat REPEAT number of times to repeat measurements (default: 10)
--load LOAD test fixture source and load resistance (default: 50)
--title TITLE title of measurement (default: )
--device DEVICE name of serial port device (default: None)
--start START starting frequency of initial sweep (default: None)
--stop STOP stopping frequency of initial sweep (default: None)
--capture capture screenshots of the measurements as movie_xx.png
(default: False)
jim@jim-P55A-UD3P:~/crystalweb$

Hello Roger,
Thank you very much for your quick answer.
My answers are in your text:

On Wed, May 27, 2020 at 08:30 PM, Roger Need wrote:

When you replace a 50 ohm resistor load with the RG-316 cable connected to the
nanoVNA you no longer have a 50 ohm resistive load. This is due to two
factors:
- RG-316 cable is only specified as a "nominal" 50 ohm characteristic
impedance. Its characteristic impedance varies considerably with frequency as
shown below.
- The NanoVNA CH1 port is also not 50 ohms as reported by others on this site.
You can measure it yourself and see what I mean.

The net effect of these two effects is that you will see a complex impedance
at the end of the RG316 that differs from 50 ohms so the balun will not be
seeing 450 ohms and the return loss will be different.

I was my understanding, that the calibration will give at the end of the 50 cm RG-316 cable
nominal 50 Ohm impedance (reference point).

One other point. The style of 50 ohm SMA load you are using is not a good 50
ohm load. They are usually made with a 51 ohm resistor with a long lead
(inductive) and have a poor contact with the load case. So this will affect
your initial Return Loss measurement

With that 50 Ohm resistor in the picture I got a good S11 Return Loss measurement.
So, this was not my point.

The problem arised when I exchanged this 50 Ohm resistor with a 50 cm RG-315 cable,
connected to the CH1 port of the nanoVNA.
The calibration with that 50 cm RG-316 cable was made before.

So, how can I improve the situation?

73, Rudi DL5FA

Some free tools to analyze Touchstone files...



Roger

They can also be imported into a spreadsheet very easily. I have done that for making plots and doing calculations based on the data.

Roger

On Wed, May 27, 2020 at 11:02 AM, <reuterr@...> wrote:

I replace now the 50 Ohm resistor at the SMA plug with a coax cable RG316
to the nanoVNA CH1.
To my surprise the S11 Return loss looks much different, than with the 50 Ohm
resistor.
See: NooElelc_Balun_9-1_S21_Loss.png.

What In am doing wrong?

73, Rudi DL5FA

When you replace a 50 ohm resistor load with the RG-316 cable connected to the nanoVNA you no longer have a 50 ohm resistive load. This is due to two factors:
- RG-316 cable is only specified as a "nominal" 50 ohm characteristic impedance. Its characteristic impedance varies considerably with frequency as shown below.
- The NanoVNA CH1 port is also not 50 ohms as reported by others on this site. You can measure it yourself and see what I mean.

The net effect of these two effects is that you will see a complex impedance at the end of the RG316 that differs from 50 ohms so the balun will not be seeing 450 ohms and the return loss will be different.

One other point. The style of 50 ohm SMA load you are using is not a good 50 ohm load. They are usually made with a 51 ohm resistor with a long lead (inductive) and have a poor contact with the load case. So this will affect your initial Return Loss measurement

Roger

RFSim99 can also handle Touchstone device definitions.

Jose, CO2JA

I am testing the NooElec 1:9 balun V1.0.
When I measure the S11 Return Loss, see NooElec_Balun_9-1_S11_Return-Loss.png,
it behaves like the original curve balun_one_nine_return_loss_comparison_to_70mhz.png.
My measurement setup is shown in photo RF_Balun_1-9_S11_DSC08237.jpg.
The secondary side of the balun is terminated with 400R + 50 Ohm.

If I want to measure the balun *Loss* I have a problem.
See the original curve from NooElec: balun_one_nine_insertion_loss_comparison_to_70mhz.png
I replace now the 50 Ohm resistor at the SMA plug with a coax cable RG316
to the nanoVNA CH1.
To my surprise the S11 Return loss looks much different, than with the 50 Ohm resistor.
See: NooElelc_Balun_9-1_S21_Loss.png.

What In am doing wrong?

73, Rudi DL5FA

The only programs I have used touchstone files with is Keysight ADS and MATLAB. However, they're usually just formatted ASCII so I would be surprised if no one else had made a parser for them.