Hobbies and Interests

As already described in the section "about me", the short profile and the biography, I have several hobbies and interests, which I will present more detailed in the following:


Mobile Communication


When I was a teenager, initially my interest for radio technologies, particularly for FM transmission developed from my interest in all technical and especially all electronical things. At about the age of 13, I was not only interested in the fact how analog radio broadcasting on electromagnetic waves works exactly, but I also looked for all transmitter sites in South-East Bavaria and neighboring Austria, informed myself which channels are broadcasted there at what frequency and explored how far each of them can be received. Also, at home I tried successfully with special antenna designs to receive stations, e.g. from Tyrol, whose signal were normally too weak to be found there.
An even more fascinating world of wireless technology opened up to me when I was 18 years with my first cell phone, a Nokia 6310, that I bought with a Vodafone contract. In the same year I bought SIM cards from the three other German networks and other GSM cell phones, on which I also partially succeeded in activating the network monitor, which is really not intended for private use, or could install such a network monitor on some phones. With this equipment I began to search the base stations of the networks. Just three months later, I had at least found most base stations of Vodafone in my area and had a good overview of how the Vodafone GSM network in my area, the Berchtesgadener Land, is built and how big the respective radio cells are. After I explored also the other three German mobile networks in this way, the Austrian networks in the northern province of Salzburg followed, and even in New Zealand, I was already looking for base stations... In addition to the structural design of the networks I also occupied myself with the functionality of the mobile communication standards GSM, UMTS and LTE. Moreover, I have been following since about 2002, the company policy and also particularly the network expansion policy of mobile network operators. Since I know the weaknesses of each mobile network in South-East Bavaria, and since I know that there is no best network, which provides coverage or even HSPA everywhere, I carry multiple smartphones with SIM cards of all German network operators with me. I think we can rightly say that I am a mobile communication freak ;-) Even until today I have kept my interest for the structural design, the functionality and capabilities of mobile networks and network standards, because even today I still collect data on the radio cells of the networks, I look at the network expansion and have even dedicated my diploma thesis to the question of how (good) car to car and car to infrastructure communication is realizable with LTE. I think I can rightly say that I have acquired much knowledge about mobile communication in the last years and possess great skills in this area. Thus I do not only know the technical details of the mobile phone standards GSM with EDGE, UMTS with HSPA and LTE or the structural design of cellular networks, but also the development of the German network operators, their outwardly visible or determinable strategies as well as the German, European and even New Zealand's mobile market in total. I think the future in mobile communication is very exciting, especially in view of the LTE development and the expiry of GSM licenses as well as the probably technologically neutral reallocation of these frequencies, which will presumably take place on the German market even in the year 2013...


Networks and Webserver


Besides my passion for radio technologies, such as mobile networks, in 2004 I discovered my interest in the Internet and also especially in the fact to constitute a more active role in the Internet - namely, as an operator of his own web servers. After I had started already in February 2002 to operate my own websites, in February 2004 I rented my first v-server. This v-server should henceforth be used as a web server for my websites, which had been hosted by webspace providers until then. I even installed my own mail server on this v-server, which henceforth accepted all my emails from the other major mail servers of large providers and saved them for me. At that time the operating system I used was the then-current version of Debian "Woody" (3.0). My first mail server I was running at that time with "sendmail". Just one year later, I hired my first dedicated server in a data center in Karlsruhe. Thereafter other dedicated servers and v-servers followed and I started in 2005 to operate my own domain name servers, so that I became with my mail system and my web servers completely independent of the services of external providers. Meanwhile I operate under the domains and Enexas.net Net83.net several dedicated servers and v-servers in data centers in Germany (Nuremberg, Falkenstein and Frankfurt / Main), New Zealand (Auckland) and France (Paris and Roubaix), which provide my websites, my name servers and my mail systems. A small overview about this can be found in the section "SK-Network" in the subsection "Server".
But I am not only interested in distant or large networks such as the Internet, mobile radio or other access networks. I am even interested in the local networking at home. So I had even a first small home network consisting of a modem, a wireless router, two computers and a notebook when most people were still using a simple DSL modem or even ISDN and had to dial in before every online session with the - in the majority of the cases - only PC. But my interest in networks was really activated by the lecture "Computer Networks" in my media informatics studies. I had passed the corresponding exam, which some other students enjoyed as much as many people enjoy mathematics in school, with the mark 1.0, while some others even didn't get the admittance to the exam due to poor results in the corresponding midterm exams... Even during the semester in which I had the computer networks lecture, I started to build a proper home network. The result is a network of gigabit cables that supplies the rooms on three floors. Via these physical lines nine virtual networks are transported, divided by nine different VLAN tags. Four of these virtual networks are terminal VLANs for network components and servers in the home network, my own PCs and mobile computers, other computers in the house and finally another one for untrustworthy guest computers. Between these VLANs mediation is only possible via the central router and its firewall. This core router is located in the computer room on the first floor together with three multi-WAN routers, three VLAN switches, four PCs and a wireless access point, which radiates a own Wi-Fi network for each of the four terminal VLANs. From there, a cable leads to a VLAN switch at the attic, which connects the network outlets of the rooms of the first floor, and from there into the basement to another VLAN switch in this basement room, that connects the network outlets the garden, as well as in two rooms of the ground floor and a second wireless access point, which radiates the same networks as the first one to gain the wireless signal. But the Internet access was still a bottleneck: Because the phone line from the telephone switching center to the house is 2.4 km long, the German Telekom did not want to provide more data-speed than DSL3000 with 3000 kbit/s in the downlink and 384 kbit/s in the uplink. Other DSL providers also could not provide more data speed as the don't have own technology in the telephone switching center in the city of Laufen, and even "Kabel Deutschland" didn't offer internet access, because the TV-cable-network in Laufen does not have back channel capability (until summer 2012). After endless vainly attempts to encourage the German Telekom to move away from their very cautious approach in switching DSL connections, I had the idea to order several DSL connections and to spread the burden of all Internet connections from my rather complex home network using multi-WAN routers across these multiple connections. Quite quickly I had to recognize when I ordered the third DSL connection that the German Telekom refused all requests of alternative providers for a free line and I learned that usually only two of the usually six phone-line-pairs that lead into a single-family house are really connected to the cable fanout. The remaining wires lead in neighboring houses where they can be applied via jumpers on free trunks. In addition, I also learned what should be ordered in such a situation at the German Telekom in order to finaly receive via a neighboring property another multiplexer-free line, which I transferred directly to their competitor Arcor for a DSL connection. But after the fourth order of a line, they sent an excavator which opened the road and uncovered two sleeves (see photos), so that I got five direct trunks to the switching center that I all occupied for DSL connections. Two of the DSL-routers are in the basement, the other three are in the computer room on the first floor. They all share the data of the respective DSL upstreams with the multi-WAN routers via a separate VLAN and also provide even a private wireless network in which only the respective DSL connection is available. So, my small home network with five DSL lines, ten routers, five VLAN switches, a normal switch and nine wireless networks that are broadcasted from seven different access points is finished. The DSL routers are mostly of the brand AVM, a multi-WAN router is from Lancom and the rest is from Cisco... A nice hobby, right? Well, I really like building such networks... I also use my network knowledge and everything I've learned about broadband technology and the telephone network of the last mile willingly again and again, when I help others to build their home networks or their telephone wiring.



Long before I was running my own webservers, I put my first website online in February 2002. At that time I got to my DSL connection a little bit of webspace and a de-domain. Therefore, I registered the domain starlight-studio.de and created a first small basic website about me and my little studio. A year later, I put my personal website under the domain stefan-karl.net online. At that time everything was designed just in a very simple way. The websites were written in pure HTML with small custom Flash animations. Only when I started to run my own webserver, I relied more on PHP with the connection to a MySQL database. Pretty soon I decided to install and use the content management system (CMS) Typo3, which I use even today for many sites. For the first time the content was completely separated from the design that was henceforward only included as a self-made design template and its content tags were replaced with the real content. Even today I still rely mostly on Typo3, but in addition also partly on WordPress, whichever is the most appropriate thing for the intended use. The design I integrate mostly as a template with markers which the CMS replaces with the content. I considered automatic replacement methods without markers for my private websites as less suitable, because I am the Template Designer as well as the administrator of the CMS and I have a more intuitive control with markers. In addition to the operation of web servers, designing websites is still a lot of fun to me and I still like publishing new websites on the internet or to renew existing ones. But my designs are generally rather simple. Intricated animations which cannot be shown on all devices meet my tastes less... A small overview about my current websites can be found in the section "about me" in the subsection "Websites".


Hiking and Nature

If you look at my interests for mobile communication, networks and webservers, the impression that I was a cellar-child whose life consists only of technical things may easily arise. Actually technology, electronics, IT and especially networks take a significant part in my life, but not my whole life! I like - quite atypical for this cliché - being outside in the nature, especially in the mountains, such as Southern Berchtesgaden area or southern Chiemgau, which is indeed situated almost on my doorstep. And I like hiking in the mountains or anywhere else in the nature, preferably near small streams or lakes. However, there is one fundamental difference to "normal" nature-loving people: I carry always various Smartphones and mobile phones with SIM cards from all German mobile networks with me when I am in the mountains or anywhere else in the countryside and usually I'm even thinking about where the next base stations are and consequently where I have network reception with these networks! Apart from this small peculiarity to always want to be connected to the digital world, I enjoy there the peace and tranquility of our otherwise stressful world like everyone else. One of my favorite places is especially the valley behind the mountain Falkenstein at Inzell, Germany with the two lakes Falkensee and Krottensee and the castle ruin at Karlstein or the Malerwinkel at the Königssee, which is at certain times even untroubled by tourists. In addition to the hiking, I also like doing tours with my bike, e.g. in the lowland forests of the river Salzach or since the summer of 2010 also in the mountains. Some photos of these places can be found in the photo gallery under "Hikes and Outdoor".



Shortly after I made my driving license for cars in 2002, I also began riding a small scooter. Then I liked riding on two wheels so much that I, as previously planned, also got my motorcycle license in the summer of 2003. Even at that time I planned to buy a decent bike some day and I already planned that it should of course not be a sports machine, but one of the now rather rare choppers. After I had moved to Munich at the end of 2004, because of my studies and invested much time for my studies in the following years, I thought only in spring 2010 again about the purchase of a motorcycle. At the end of May 2010 it was done: I bought a used but little driven chopper that I drove home at the same day from the Allgäu-area in south-west Bavaria: It has become a Yamaha XV 535 Virago! The previous owner had imported the motorcycle from the United States, which means that my Virago has a special feature: A mile speedometer! It also has brought-forward footpegs from Falcon and many parts are made of chrome, so that it shines beautifully! On the adjacent photos you can marvel at it :-)
With this beautiful chopper I like driving in the mountains and other beautiful landscapes. Also tours throughout Bavaria, such as the Franconian Switzerland or to the festival "Summer Breeze" I have already done with the Virago. Photos of some motorcycle tours can be found in the photo gallery. But I don't like driving particularly fast with the chopper or to rush through tight corners, I rather enjoy comfortably sliding on a beautiful machine on the streets and preferably in beautiful landscapes. This gives me a sense of freedom and it is a part of me, as many songs, that are closely related to my feelings, also do!


New Zealand

Nature and freedom? The absolute maximum of it I find in my favorite country New Zealand! But one by one: How did I begin to think of New Zealand? After high school I had the idea to take a trip through the USA. With a rented car I wanted at first to drive around Florida and then do a tour into the middle of the country up to Arkansas and beyond. A foundation stone for this idea seemed to be that my uncle did a similar U.S.-tour some years ago. A little note: I, a mobile communication fan for years, already planned to buy an analog mobile phone from AT&T in order to be optimally reachable. Yes, I know... but communications networks are important to me... Unfortunately at that time there was no one who wanted to join me at such a trip on our own and I didn't want to travel completely alone, so that this plan fell through. Since I rarely get to go to the cinema, I had not seen the Lord of the Rings movies there. A little later, in the winter 2004/2005 I borrowed the DVDs from a friend (in the meantime I own them all by myself) and was immediately inspired by the landscapes in the films. After a short search I found out that everything was filmed in New Zealand and most of the landscapes there even really exist. I informed myself more about New Zealand and was very quickly very excited about this country. A little later, in the summer of 2005, I also badly needed recreation and vacation after the fiasco with the electrical engineering studies. So I decided to take the opportunity and travel alone to the other side of the world to New Zealand. For someone like me, who had previously never flown with the exception of a small round-trip flight, the 27-hour flight was already a certain challenge. After having arrived in New Zealand, more precisely in Christchurch, I made a nearly three-week tour through New Zealand from Christchurch to Auckland. On my route were, besides the cities Christchurch, Queenstown, Wellington, Rotorua and Auckland, also the vast plains of Central Otago, the misty Fjordland, the forests and glaciers along the rugged West Coast of the South Island, the geysers in Rotorua, the Bay of Islands and Cape Reinga. Unfortunately, less than three weeks were a too short time to explore this diverse country in sufficient detail. A day before leaving I made in Auckland the decision, to definitely return in the next few years. I did this in August 2007 after I had completed my undergraduate studies in media informatics in just three semesters and stayed this time for a month in my favorite country. Again, I travelled first to Christchurch to do a tour through the South Island from there at first. Of course I travelled to the Fjordland again where I visited besides the world famous fjord "Milford Sound" also the misty "Doubtful Sound" this time. From Queenstown I went once again to Glenorchy in order to drive up the Dart River by a beautiful pristine valley with a Jet Boat. This time I didn't fly to the Fox Glacier, as I was at the west coast but made a detour to Lake Matheson. In Punakaiki I hiked to the Pancake Rocks and contrary to the last time I drove this time also twice by train: The Tranz-Alpine from Christchurch across the Southern Alps to Greymouth and the Tranz-Costal down the east coast from Picton to Christchurch. A special highlight was the hike in Abel Tasman National Park from the Bark Bay by virgin forest and many small bays to Anchorage. On the North Island, I did this time in addition to a trip to the geysers in Rotorua, to the Bay of Islands and to cape Reinga also a two-day trip to the Coromandel Peninsula as well as from Auckland a day out in Waitakere Ranges to the volcanic-sand beach at Piha. A few photos of my New Zealand travels in the years 2005 and 2007 are in the photo gallery!
New Zealand is simply my favorite country! It offers with beautiful bays, sandy beaches, jungles, high mountains with glaciers, partly misty fjords, vast plains, deserts, sand dunes and big cities pretty much all types of landscapes on earth! Even the people living there, the Kiwis, are quite friendly, funny and relaxed. The country is western-oriented and also all the infrastructure such as roads and telecommunications networks are at good western level. Since the cost of living is lower than in Germany and a computer scientist has good job prospects there, for me New Zealand would be quite ideal for living. And indeed, I have already thought about emigrating to New Zealand. These plans, however, are off the table for now, because even though I like New Zealand very much, I still hang too much on my home in south-east Bavaria. But I surely will make more holidays in this beautiful country at the other end of the world!


Castle Ruins, mystical Places and mystical Things

Something that my favorite country New Zealand has unfortunately not in comparison to Germany, is a centuries-old history. In contrast to New Zealand in Germany and in other European countries beautiful castles and castle ruins from the Middle Ages or even earlier times can be found. But precisely these contemporary witnesses of bygone times fascinate me! I'm thinking sometimes how the daily life was a few centuries ago. Maybe it was far more uncertain but probably somewhat more intense than in today's rational time. While nowadays even changing a light bulb for many average people is a huge problem that these people have to report immediately on Facebook, in those days it was at many times almost every day a matter of life and death. Even the few news mostly distributed by travelers were more important than in our information-flooded modern world. Despite all the achievements of our modern times, which I do not want to miss, I attribute more intensity and passion to those old days. But not much remained of these earlier centuries. Nowadays only a few buildings such as castles, palaces and castle ruins testify to that. I am particularly interested in castle ruins. On the one hand, you can especially see from the ruins that they do not belong to our time but to the past. On the other hand, these in the past often fiercely contested places where many people lived, were glad and suffered, are today often situated quietly, lonely and deserted on mountains or in the woods apart from our today's civilization. But even these often overgrown stone buildings still testify silently to the past. That is also a reason why I like staying there. Another reason is the silence on these once troubled places. Apropos my favorite place is the castle ruin Karlstein near Bad Reichenhall (Germany), of which you can find photos in the photo gallery under "mystic places and ruins" as well as of other ruins and mystical places. Such stone witnesses of the past are for me - as well as some natural places (e.g. lakes or valleys) - places with a certain charisma that are fascinating me and make me like being there. Some people call this magical places or places of power etc., but I think it's inappropriate and would rather speak of mystical places. By saying that I mean mostly quiet places where you feel or think of something that you otherwise mostly don't feel or think, e.g. the past, peace and relaxation, or something else... Anyway, I like being at such peaceful places far away from the hecticness - it's a good compensation from everyday life!

But besides the silence and the atmosphere of the past, I am interested in some of those places in particular because of some other reason namely those places to which legends and myths have grown up! I am especially interested in allegedly inexplicable things, myths and legends because I want to make my own picture of it and uncover such eventually existing inexplicable things. So I am for example interested in the discoveries and the theories of Erich von Däniken or in the whereabouts of the Amber Room. However, I don't fully believe in any theory, but I rather seek critically for the underlying truth! This is even visible in all areas of my life: Hidden, mystical or inexplicable things and enigmas interest me or make one thing really interesting to me. I like dealing with these things critically and want to get to the bottom of them!


Music and Movies

Music is a very important way to express feelings and moods or to get us into a certain mood. The music that a person listens to is therefore a reflection of his feelings. It is the same with movies. You can get carried away by movies and they evoke certain moods or you watch certain movies, because you are just in a right mood or want to be in a certain mood. Therefore, for a person like me, who certainly has lively emotions, music and films are very important - they constitute a significant part of life for me! So I hear often and deliberately music. Much of it is rock (including gothic rock and metal), some of it is rather electronic music (including synth-pop) or New Age, another kind is even classical music. All kinds of music that I listen to have one thing in common: It conveys feelings and moods, sometimes it is even melancholy or even epic. A small selection of music that I like listening to is found in the section "Taste in Music". In 2001, I started building myself a small recording studio for electronic music, the Starlight Studio, consisting of a few synthesizers, a mixer and a music computer with Logic Audio Platinum. But in the last few years I didn't do much anymore here, mostly due to reasons of time. All of my favorite movies have an exciting story, they ideally involve secrets and some, such as "The Mists of Avalon" have even a mystical touch. I like watching movies - but mostly on DVD. For that I built myself already in 2002 a small home theater system. But until now I go to the cinema quite rarely, because there are usually not many opportunities. My favorite films include the Lord of the Rings trilogy, the drama "In My Father's Den" which is also originating from New Zealand, "The Mists of Avalon", "Midsummer", "Into the Wild" and approximately the first half of "The Gathering".



Another contradiction to the stereotype of the purely rational computer scientist is that I don't dismiss astrology as rational (with our today's knowledge) not explainable or provable. Although I have to say quite clearly here that I'm a pretty rational person that likes to prove issues, but there are exceptions as well, because I also believe that the mankind is far away from knowing everything and from being able to prove everything that is true. But I don't give every unprovable hypothesis the chance that I assume it could be true, but only those where I have an indication for that. And especially in astrology this is given by the fact that I am again and again surprised to learn that a person's character can actually be determined by his birth chart. But I'll start now at the beginning of my interest in astrology: At high school there were always project days for the smaller classes at the end of the school year. In fifth grade, I was divided in an astrology project which actually was for me only the second or third choice. The project was conducted by a teacher of mathematics and physics by the way... Firstly, all participants should indicate their exact dates of birth (date of birth, time of birth and place of birth) and then everyone got printed a graphic representing his birth chart. A birth chart shows the positions of the planets in the twelve signs of the zodiac at the time of birth. The planets represent certain aspects of the character or life like the Sun ("Zodiac Sign") for the basic character, Mars for enforcement/force/drive, Mercury for thinking/communication, Moon for feelings and Venus for love/partnership. The Ascendant indicates how one acts outwards or deals with his environment. The MC (Midheaven) is the goal of life. The twelve zodiac signs, however, indicate the characteristics and tendencies. In the astrology project we were told about all this and everyone could interpret his own birth chart, using a piece of paper on which was written what every zodiac sign means. I was very surprised how well even this interpretation done by way of "construction kit"-method fitted to me and was a little bit more interested in astrology from then on. So I learned later to interpret also the aspects between the constellations and I bought in 1999 with Astro-Star-2000 my first astrology program in order to create also the birth charts, which I interpreted, by myself. From then on I started to create and interpret birth charts for more people and was always amazed how well these described the persons in question. Thereby I was critically about all this, like about many things, but I could rule out, however, that general statements were made with which many persons could have identified. But I really take no stock in future analyzes and the houses system! Astrology means to me only to analyze a person's character with the help of the constellations and the aspects of the birth chart. And especially that has been working remarkably well for 17 years now, so that I can't laugh at astrology in this case, though I haven't found a coherent rational explanation for it.