Below I’ve experimented with gnuplot, in few examples:
Reading and displaying data from a file Reading and displaying data from a GPIB-connected device (measurements from a voltmeter with open input connection) Reading and displaying data from a GPIB-connected device (measurements from a voltmeter connected to a 10 volts voltage reference) gnuplot is a nice tool for plotting data. Start gnuplot to enter plot commands. I tried this tool when analyzing a strange behaviour of a Zener diode.
5 1/2 DMM from the 80ies. It has a hidden 6 1/2 digit mode. My meter does not have the True RMS module for AC. But it has a connector that emits the measurements via RS232 (not tested).
While all date codes from the digital board are from 1984, I found also some chips from 1988. So the meter is from 1988 or later.
It looks like the meter was in “official” use until 2023, because there is a safety sticker from this year.
ITT teddy 4 came as not working together with another radio I bought from an ebay seller. This radio is from early seventies, I estimate.
The radio is medium-sized, not a small one, but also not a large one. Sound is quite impressive, it has more bass than I expected. Sound, compared to e.g. ITT Junior automatic, is much better.
This picture was done after repair and cleaning all caging parts.
I wanted to replace a 4x1,5 volts baby cells power arrangement in an old radio ITT teddy 4.
New battery should be the ubiquitous 18650 cell. It offers about 4.2 volts, so I looked for a solution that does up conversion to about 6 volts, and that offers a USB connector to load the cell.
Best would be to have also some battery protection (undervoltage protection, current overload protection).
I found two interesting modules for further analysis.
This is a great DMM from the around 1979.
It is called “Microvolt Digital Multimeter” because it has a resolution down to 1 microvolt. Even more interesting is the current range, going down to 1nA (nanoampere) resolution.
This is due to the DC range 20 mV (20.000mV) and DC current range 20 µA (20.000µA). Finally, it has a 1mOhms resolution on 20.000 Ohms range.
This multimeter is great to measure small currents, e.
Some tweaks to make OpenSuse work as expected. This was done with version 15.4 but usually these topics are to be done for every new version. I list them here to not forget how to fix the issues.
Make dmesg work dmesg does not work for non-root users, it needs a tweak to do this.
sysctl -w kernel.dmesg_restrict=0 bash -c 'echo "kernel.dmesg_restrict = 0" >> /etc/sysctl.d/10-dmesg-non-root.conf' See https://forum.ubuntuusers.de/topic/schikane-mit-dmesg/
Make external soundbox work via bluetooth This is another ugly story.
Some remarks to set up an existing empty OpenSuse Leap notebook (HP Elitebook) for FT8.
I started with HamPI on a Raspberry for the same task, but I did not like the many parts flying around on my desk (Raspi, small monitor, mouse+keyboard, powers supplies for all, active USB switch). So I decided to replace this solution with an older HP Elitebook 840 G3.
To not rely on available/non-available packages, I usually build all the tools from source.
Trapider TE-15 Grid-Dipper.
Frontplatte mit Frequenzeinstellscheibe, Anzeigeinstrument sowie Frequenzeinstellknopf und Ein/Aus- / Empfindlichkeitsregler: Originalverpackung nur in Teilen vorhanden. Man sieht das Gerät, Spulen für die unterschiedlichen Frequenzbereiche sowie Ohrhörer und Anleitung. Zwei der Spulen, hier für 40-140 Mhz und 120-280 Mhz: Das überschaubare Innere: Transistoren 2SB422: Hier eine Germaniumdiode: Ein Scan der Anleitung: Das Gridmeter in Nutzung. Es ist eine Frequenz von 700 Khz eingestellt. Die Meßspule liegt direkt über einer Spule eines Testaufbaus (Meissner Oszillator).
Morsetasten HI-MOUND Manipulator MK-706 Japanisches Double Paddle für Squeeze Keying. 950 Gramm Gewicht
Junker M.T. Patent von 1931. Seit 1934 in Bad Honnef gefertigt.
Meine Taste ist “Ausführung Bund”, also für die Bundeswehr gefertigt. Im Vergleich mit anderen Tasten würde ich die Taste als nach 1960 einordnen (aber wissen tu ich nix).
Siehe auch https://de.wikipedia.org/wiki/Junker_Morsetaste_M.T.
Math formulas and symbols Use MathJax for this.
How to add to Hugo See https://stackoverflow.com/questions/64050359/how-to-use-markdown-syntax-to-write-math-in-hugo or here : https://bwaycer.github.io/hugo_tutorial.hugo/tutorials/mathjax/
Add these lines:
<script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script> <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
See: https://www.morch.com/posts/2021-07-24-mathjax-in-hugo/
<script type="text/javascript" async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?..."> </script> See: https://bwaycer.github.io/hugo_tutorial.hugo/tutorials/mathjax/ and https://www.mathjax.org/cdn-shutting-down/.
To the layout file of your hugo template. I use theme mainroad, and added the lines in themes/mainroad/layouts/_default/baseof.html, in head-section of html.
Tests $$f_{res} = \frac{1}{2\pi\sqrt{LC}}$$
This shows as Mathjax \(a \ne b\), but this doesn’t (a \ne b)
