Tag Archives: Alexander von Obert

Alexander’s report from Ham Radio Friedrichshafen


The Friedrichshafen exhibition grounds. (Photo: Ham Radio Friedrichshafen)

Many thanks to SWLing Post contributor, Alexander (DL4NO), who shared a few notes with me from his visit at the Friedrichshafen Ham Radio convention. Alexander has kindly allowed me to post his notes here on the SWLing Post. Alexander writes:

The first booth I visited was of Dokufunk (http://www.dokufunk.org/). They collect QSLs and other information about wireless history for scientific evaluation. Its head Wolf, OE1WHC, was a moderator for the Austrian shortwave service which does not exist anymore. But ORF still supports Dokufunk. They have a large archive and even the equipment to digitize large quantities if information. I brought them a package of ham radio periodicals, mostly issues of DL-QTC, the predecessor of cqDL, and got some QSPs (magazine of OEVSV) back. I collect those periodicals to gain and provide access. Seehttp://www.dl4no.de/thema/amateurfunk-zeitschriftenarchiv.htm, catalog at the bottom.

The flea market filled three exhibit halls. If you needed a tube heating for your shack you had a wide choice, from radios to ham equipment to scopes. On the newer side you could get Windows XP packages with the appropriate hardware.

Flea Market Photos Courtesy of Ham Radio Friedrichshafen

A3: Stand mit historischem Radiogeräten (Photo: Ham Radio Friedrichshafen)

A3: Stand mit historischem Radiogeräten

A3: Stand mit Empfängern und Messgeräten

A3: Stand mit Empfängern und Messgeräten (Photo: Ham Radio Friedrichshafen)

A3: Stand mit Empfängern und Messgeräten, hier zwei Schweizer an einer historischen Feld-Telefonzentrale

A3: Stand mit Empfängern und Messgeräten, hier zwei Schweizer an einer historischen Feld-Telefonzentrale (Photo: Ham Radio Friedrichshafen)

A3: Koffer mit Ham-Radio-Aufklebern aus mehreren Jahrzehnten

A3: Koffer mit Ham-Radio-Aufklebern aus mehreren Jahrzehnten (Photo: Ham Radio Friedrichshafen)

A3: Alte Radiogeräte

A3: Alte Radiogeräte (Photo: Ham Radio Friedrichshafen)

A3: Alte Empfänger und Radios

A3: Alte Empfänger und Radios (Photo: Ham Radio Friedrichshafen)

A3: Stand mit Empfängern und Messgeräten

A3: Stand mit Empfängern und Messgeräten (Photo: Ham Radio Friedrichshafen)

Yaesu, Icom & Co where there, of course. A large part of Hall 1 had booths for most of the European ham radio societies and other entities. Several attractions for the youths were there: A fox hunt around the hall, possibilities to solder simple circuits and more. The exhibit center even provides a kindergarden.

A1: Hilberling PT 8000A

A1: Hilberling PT 8000A (Photo: Ham Radio Friedrichshafen)


A1: ICOM (Photo: Ham Radio Friedrichshafen)

A1: Wimo, BABY Loop

A1: Wimo, BABY Loop (Photo: Ham Radio Friedrichshafen)

A1: YAESU Funkgeräte

A1: YAESU Funkgeräte (Photo: Ham Radio Friedrichshafen)

Hamradio had lots of presentations. The “SDR Academy” run all over Saturday – completely in English. See http://www.sdra-2016.de. Last year’s presentations are on Youtube. Search for “SDRA-2015”.

My presentation was titled “HAMNET On 70 cm – Possibilities and Limitations”. I should explain that HAMNET is our way to use the TCP address space reserved for Ham Radio use. Starting in Germany and especially Austria we use more or less standard WLAN equipment to build a ham radio intranet. User access is mostly on 2.3 GHz and links on 5 GHz. Where we have gaps in the wireless coverage we use Internet wormholes. This way you can access for example packet radio sites in Canada. See http://hamnetdb.net.

2,3 GHz and up means exclusively line-of sight connections. Quite some OMs cannot reach access points this way. The only alternative up to now has been VPN connections through the Internet. I think we could provide relatively fast access on 70 cm. Here in Germany we have two 200-kHz channels for such uses. They were defined in the 1980s for packet radio access up to 76 kbps. This technology is next to dead.

Theoretical calculations show that we could provide up to 1 Mbps and cover up to 50 km if we use modern modulation schemes. You could even improve throughput by making TCP/IP less gossipy. I proposed to use SDR blocks like HackRF or LimeSDR and combine them with a RF frontend (filter, preamp, PA, fast switching). The hardware is more or less readily available, but this is mostly a software topic. While HAMNET relies on standard WLAN equipment with all its limitations for ham radio usage, this system could be completely open. We could it adapt to all our needs and ideas. In the end we could port it back to the microwave bands.

Even if we only work on the lowest protocol levels this will pose quite some challenges. We would need programmers with quite varied expertise from TCP/IP protocols to SDR technology. My presentation was to attract such people. Personally I will not program anything. As a technical writer with a quite wide expertise I might be a bracket for the project and write documentation for it.


A “Peltier Lamp”: The candle heats one side of the Peltier element while the other is cooled by the heat sink. This produces enough electricity to light a LED. (Photo: Alexander DL4NO)

At the opposite end of the exhibit center another fair went on, called Maker Faire. In former times you would have called it “make it yourself”. The exhibits there went from computer modding to 3D printing, knitting and also ham radio. For this I modified my presentation a bit: “WLAN Below 1 GHz – Do You Want To Program For It?” The technology I talked about is near hot topics like Internet of Things or traffic telematics.

Booth of a high school showing the robots they built. (Photo: Alexander DL4NO)

Booth of a high school showing the robots they built. (Photo: Alexander DL4NO)


Booth of a high school showing the robots they built. (Photo: Alexander DL4NO)

vy 73

Thanks so much for sharing your notes from Friedrichshafen, Alexander. I look forward to attending one year myself!  I’m fascinated with the fact that the bulk of the event is indoors–what an incredible venue.

Any other Post readers attend Ham Radio Friedrichshafen? Please comment!

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Listener Post: Alexander von Obert

Analog Radio DialShortly after posting my plea for your radio stories, I received several replies, including this excellent story from SWLing Post reader, Alexander von Obert, who lives in Germany.

I have created a new series called Listener Posts, where I will place all of your personal radio histories. If you would like to add your story to the mix, simply send your story by email!

In the meantime, many thanks to Alexander for sharing his personal radio history:

Alexander von Obert (DL4NO)

My fate was sealed on my 12th birthday: As a present I got a redio experimenting kit (Kosmos Radiomann for the Germans among the readers). I could build a diode receiver (AKA detector receiver with a Germanium diode) from it. Adding an EF98 pentode (anode voltage 12 V) I could even build a tube audion, a 0V1 for the hams among the readers.

rbfjWithin a few months I outgrew it. My father, an engineer himself but completely absorbed by his job, showed me where a soldering iron gets hot. I managed to get hold of old radio and TV sets including Audions from the 3rd Reich area (“Volksempfänger”). First I simply dismantled them out of curiosity. Then I discovered the public library of my home town. The author of the time was Heinz Richter with titles like “Radiobasteln für Jungen”(radio building for boys).

Naturally I even tried to use these radios – especially those I managed to repair. I even listened to shortwave stations. In these times you found quite some German transmissions, notably from the BBC and Radio Sweden. Later, when my English knowledge blossomed, I discovered an even wider universe out there.

Then came the time where I wished to transmit myself. I never considered to do a radio program, I enjoyed experimenting with my equipment to much. Here in Germany transmitting without proper license was a criminal offence so my tests were few. CB had not been introduced here in Germany at that time, but I learned about ham radio. Somehow I found out about my local club and their license course. So I got the proud owner of the call DB1NO, a VHF/UHF license without Morse code test.

A short time later started my military service. I had to do quite some night shifts, a good opportunity to train Morse code hearing. When my comrades saw my cassette recorder they disappeared knowing about the “music” I would be listening to over the next half hour. After two years I did the code test. I have been DL4NO ever since.

No question about it: After my military service I got an electronics engineer. What I learned at the university I quite often considered as the theoretical background of things that I had known before. In that time I discovered microprocessors. You had to build your machines by yourself. My first computer used a regular cassette tape recorder as “mass storage”. Only the fourth homemade machine had a floppy disk drive – of the 8″ form factor variety, with about 1 MB of capacity per medium. I could only laugh about the first IBM PC with its 320 kB floppies.

During that time ham radio was mostly a social activity for me. I held contact with the OMs around on 2m FM and had no shortwave station at all. Microprocessors, studies, and later my first job, occupied most of my time. OK, I even had discovered girls 🙂

Now, as my job slowly settles down, I have upgraded my ham radio activities. I have built a mobile station that can operate from 7 to 440 MHz. My most important objective is to reduce the effort as far as possible and to stay within the traffic regulatory. For example I have proven that you can operate a 100W SSB station from a standard 12V outlet. Down to 14 MHz you can even use magmounts without really bad effects.

vy 73

Alexander also adds this note:

How I operate my station from a standard 12 V outlet in my car is described at http://www.dl4no.de/thema/mobil-st.htm. The picture and the circuit diagram  at the bottom of the page should be clear enough even if you don’t understand German. At http://www.dl4no.de/thema/mobilbe0.htm you see how a magmount antenna works on 20 m. The magmount has 200-300 pF to the roof of the car. This is an impedance of about 50 Ohms, that can be compensated. The magmount moves the resonance frequency a bit higher as you can see in the SWR diagram.

Many thanks, Alexander, for sharing your story! Readers, be sure to check out Alexander’s ham radio website at http://www.dl4no.de.

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