Learning Morse Code in 2025

What’s Morse Code?

Morse Code, also known as Continuous Wave (CW), is one of the oldest ways of electronic communication. You might also know the term from movies, when in emergency situations someone encodes Morse Code in hitting a pipe with a hammer, and someone else picks this up in listening to the sound transmitted by the pipe.

~40 characters get encoded into sequences of

  • short dots, also called “dits”
  • and longer dashes, also called “dahs”

For sending out morse code, one has to translate sequences of words/numbers into the matching sequences of dits and dahs. The length of the dahs is defined as “three times the length of a dit”. Also the spaces between the characters and between the words are defined, allowing the other side to pick up the transmission.

2025-05-11    
Bike trip to Tochigi and rice planting

How it started

A friend owns rice paddies in Tochigi-ken, the district north of Tokyo where I live. Around the beginning of May, the rice planting is done. Since some years I attend the rice planting: initially going by train, and now for the third year by bike.

I can not go by bike right at the day of planting, it’s just to far. So I go to Utsunomiya, stay over night, and then at the day of planting go another 30km. My friend can just pin down the day of the event one week in advance, as weather should be good and a neighbor with special equipment needs to have time. As soon as I heard about May 3rd (a Saturday) would be this years rice planting, I started to lookup hotels.

2025-05-05    
Living in Japan: How does it compare to Germany?

With the right wing parties in Germany getting stronger, my Mastodon timeline gets posts from people considering to move to other countries, temporarily or forever. Japan is known for being peaceful, rich of culture, and is often called out as potential destination - so as a German living in Japan since 8 years, I will try to look at the relevant aspects. Maybe this sparks also others living in foreign countries to report?

2025-02-22    
Emulating architectures with qemu: which performs best?

Virtualization? Emulation?

What are these, after all?

  • Virtualization in our context here means that when a guest operating system does computations, these get directly offloaded to the hypervisors cpus. One of the benefits is performance, one of the downsides is that the guests cpus need to exactly match the hypervisors cpus, or a subset.
  • Emulation means that the computations are done in software. With this, host/guest architectures can be different. As a downside, this is slower than virtualization.

Using emulation, we can for example start a x86 based system, and then emulate completely different architectures like ARM or sparc64. How much performance does that cost us, how much power does this consume?

2025-02-07    
The health systems in Japan and Germany

I’ve been living in Germany and Japan, let’s look at some aspects of the health systems.

Rundown of a typical doctor visit

I’m entering the doctors office at 10:30 on a weekday. The naming is already interesting: in Japan, the normal places where doctors investigate and treat patients are called clinic (クリニック), which sounds like the German “Klinik” - but in Germany these are big complexes to treat patients, so in English “hospitals”.

2025-01-19    
Holiday season side quests

Capturing some projects of this holiday season. Partly to get a feeling of having accomplished something, and partly as reminder to continue the unfinished projects.

German HAM radio exam

Right at the start I was sitting down in the German HAM radio exam in Munich. There are 3 levels of HAM radio certificates in Germany. You can apply for the highest one, work through various exam sheets, and if you only pass one of the lower levels then you can walk home with that lower level certificate. I had started quite late to look into the material, with website 50ohm. I felt quite comfortable in the material of the lowest level, and had then started to look at the material for the higher ranks. The exam was multiple choice, I was directly informed that I passed the lowest of the 3 levels, and can now within 2 years try the higher level exams again without having to do the law exam a second time.

2024-12-29    
A simple LED setup, controllable via wlan with WLED

What’s this about?

Since a while I was wondering how to setup a chain of LEDs, where each LEDs colour and brightness could be assigned by me. In Germany I got 2 LED chains which turned out to just allow pre-programmed colours and blink patterns. I’m looking for full flexibility, so I could also for example deploy them behind the monitor and have them shine in the dominant colours of the current movie scene.

2024-10-20    
Bringing IPv6 into the LAN Blues

What the ISP offers

I’m using NTT flets as physical provider (fiber), and Biglobe for the packets ontop. Regarding IPv6, Biglobe allows on a webfrontent to request v6, which I did. Then they offer 2 options:

  • IPv6オプション (“option”)
  • IPv6オプションライト(“option light”)

I was first on the former, then switched to the latter. Their site on this. With both of these options, I get IPv4 via PPPoE tunnel, and IPv6 plainly onto my ethernet interface facing towards the ONU/modem.

2024-10-06    
Debianizing the Star64 board

Note: I’ve taken out the IPv6 pieces here and moved them to a dedicated blog article.

Since the beginning of 2024, I run my own router. I’m using NTT flets GBit fiber as physical provider, and Biglobe as ISP ontop - other ISP’s do the IPv6 things differently. I started with 2 OpenWRT routers, after both of them went defective, I run the Star64 RISC-V board as router, with this functionality:

2024-09-29    
Searching the best resolution for a monitor

So.. I got a new monitor, the INNOCN 32M2V.

Which resultion can I drive it with, from my Thinkpad T590?

Investing the Thinkpad T590 capabilities

My daily driver at home is a Thinkpad T590, with Intel i7-8665U CPU.

  • First limitation is the GPU, the Thinkpad has a Intel UHD Graphics 620, which is imbedded in the processor. Intel lists for this cpu a maximum of 4096x2304@24Hz for HDMI output, and 4096x2304@60Hz via DisplayPort.
  • The T590 has a builtin HDMI1.4b port, that allows 4096x2160@24Hz, 3840x2160@30Hz, 2560x1440@60Hz and 1920x1080@120Hz. Via HDMI connection to the monitor, I get these listed as available in the output of ‘wlr-randr’.
  • Sadly, the T590 does not have a DisplayPort. DisplayPort1.4 would be capable of: 3440x1440@240Hz/144Hz/360Hz, 4096x2160240Hz with DSC, 3840x2160@120Hz / 10 Bit Chroma / HDR

The Thinkpad has 2 USB-C ports, with different capabilities:

2024-09-02    
Monitor refresh in 2024

Choosing a monitor is hard! When you buy shoes, you try them out.. but you just know for real after wearing them for some weeks. We might see monitors at stores, or try to get advice from others - but everybody has different use styles, so it’s hard to decide for a model.

What I use the monitor for:

  • working with multiple terminals, but not more than 3 or 4 on one screen. I heavily switch between virtual screens.
  • I use webbrowsers, when these are in Japanese, I often have to increase the font size
  • more rarely: watching a movie or a drama, or playing

The previous monitor

In 2016, when I came to Japan, I got a 27" monitor at Bic Camera, one of the huge electronic stores in Tokyo. This was an I-O DATA LCD-MF276XDB, introduced 2014, with ADS panel. Maximum resolution 1920x1080, refresh rate 60Hz, builtin speakers. I use the monitor heavily, but was looking for something new. At work, I got a Lenovo one, liked the 2560x1440 resolution, and more vivid colours.

2024-08-10    
Playing with Software Defined Radio (SDR)

While last years summer in Germany became the Retro summer, this time I took the RTL-SDR software defined radio with me for playing. RTL-SDR is a usb2 stick which you can plug into a computer, attach an antenna, and then have a look what’s “in the air”.

Software

I’m using the antennas which I got with the RTL-SDR device: 2 teleskope sticks with length of up to 1m each. Main issue: for good reception, I place the antenna directly on the attic. But I want to be on the lower floors for sitting down and using the SDR. So I setup an older Thinkpad x200 with Debian Bookworm, and did setup that with the RTL-SDR device and the antenna on the attic.

2024-07-28