bug: NanoVNA Saver crash after calibration

[w8srd]

20230503-1

NanoVNA-Saver version:(s) nanovna-saver_V0-5-3, nanovna-saver_V0-5-5, nanovna-saver_V0-5-0

crash happens as soon as "Calibration Assistant" completes. Manual calibration returns these messages when "Applied" : "Error during sweep, stopped, Could not configure port:(5,'input/output error)" and "Two of short, open and load returned the same values at frequency 50000Hz"

Calibration of the device without NanoVNA Saver works.

**Current behavior:**Will not finish calibration

Was working a couple days ago

Expected behavior:

Calibration completes and I go about using Saver to Analyze antennas

Steps to reproduce:

just run it. every time it runs it happens.

Related code:

insert short code snippets here
```I dont code I use the device and pc software on Ubuntu Linux 20.04

**Other information:**

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![Screenshot from 2023-05-03 10-01-28](https://user-images.githubusercontent.com/128179432/235955696-05eec6a5-8e48-471f-8510-7d6df1c6502a.png)
![Screenshot from 2023-05-02 21-58-08](https://user-images.githubusercontent.com/128179432/235955732-6541113d-b761-4904-aaf9-28c16a109e24.png)

[radi8]

Probably related, NanoVNASaver 0.5.5
Crashes after completing calibration and I attempt to save the calibration by clicking on save. I am using the
NanoVNASaver.linux_modern.zip release. The debug trail below
73 Graeme ZL2APV
NanoVNASaver 0.5.5

Copyright (C) 2019, 2020 Rune B. Broberg
Copyright (C) 2020ff NanoVNA-Saver Authors

This program comes with ABSOLUTELY NO WARRANTY
This program is licensed under the GNU General Public License version 3

See https://github.com/NanoVNA-Saver/nanovna-saver for further details.

libGL error: MESA-LOADER: failed to open iris: /usr/lib/dri/iris_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
libGL error: failed to load driver: iris
libGL error: MESA-LOADER: failed to open iris: /usr/lib/dri/iris_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
libGL error: failed to load driver: iris
libGL error: MESA-LOADER: failed to open swrast: /usr/lib/dri/swrast_dri.so: cannot open shared object file: No such file or directory (search paths /usr/lib/x86_64-linux-gnu/dri:$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
libGL error: failed to load driver: swrast

(nanovna-saver:6625): Gtk-WARNING **: 11:42:00.060: Could not load a pixbuf from icon theme.
This may indicate that pixbuf loaders or the mime database could not be found.
**
Gtk:ERROR:../../../../gtk/gtkiconhelper.c:494:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /usr/share/icons/Mint-Y/actions/16/image-missing.svg: Unable to load image-loading module: /usr/lib/x86_64-linux-gnu/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-svg.so: /lib/x86_64-linux-gnu/librsvg-2.so.2: undefined symbol: pango_attr_overline_new (gdk-pixbuf-error-quark, 5)
Bail out! Gtk:ERROR:../../../../gtk/gtkiconhelper.c:494:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /usr/share/icons/Mint-Y/actions/16/image-missing.svg: Unable to load image-loading module: /usr/lib/x86_64-linux-gnu/gdk-pixbuf-2.0/2.10.0/loaders/libpixbufloader-svg.so: /lib/x86_64-linux-gnu/librsvg-2.so.2: undefined symbol: pango_attr_overline_new (gdk-pixbuf-error-quark, 5)
Aborted (core dumped)

[michaesc]

The crashes appear for different reasons at the end of a calabration run. Some are SIGSEGV and others are missing files. For example:

libGL error: failed to load driver: swrast
NanoVNASaver/Calibration.py:421: RuntimeWarning: invalid value encountered in divide
Traceback (most recent call last):
  File "NanoVNASaver/Charts/Square.py", line 50, in paintEvent
  File "NanoVNASaver/Charts/Square.py", line 84, in drawValues
  File "NanoVNASaver/Charts/Square.py", line 71, in draw_data
  File "NanoVNASaver/Charts/Square.py", line 146, in getXPosition
ValueError: cannot convert float NaN to integer
Abgebrochen (Speicherabzug geschrieben)

libGL error: failed to load driver: swrast

(nanovna-saver:1754876): Gtk-WARNING **: 12:15:21.706: Could not load a pixbuf from icon theme.
This may indicate that pixbuf loaders or the mime database could not be found.
**
Gtk:ERROR:../../../../gtk/gtkiconhelper.c:494:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /usr/share/icons/Yaru/16x16/status/image-missing.png: Format der Bilddatei unbekannt (gdk-pixbuf-error-quark, 3)
Bail out! Gtk:ERROR:../../../../gtk/gtkiconhelper.c:494:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /usr/share/icons/Yaru/16x16/status/image-missing.png: Format der Bilddatei unbekannt (gdk-pixbuf-error-quark, 3)
Abgebrochen (Speicherabzug geschrieben)

I'm using the NanoVNA-F V2 Sysjoint for this SIGSEGV test.