I’m currently on a business trip in Namibia, but on the way here, I had a six hour layover in Frankfurt, which is just enough time to hop the train downtown (S8 or S9 to Hauptewache, about 4.50€, which seemed a bit pricey). From there, it’s a fifteen minute walk through an historic area and then across the Main River to the museum district. Just past the world cultural museum, a few tempting antennae loom over the Museum für Kommunikation.
Those antennas are right above the ham radio station located in the museum, Funkstation DL0DPM. Unfortunately, my plane landed just about the time the station was closing for the day and I wasn’t able to visit the ham station, but I’ll put in on the itinerary for the next time I find myself in Frankfurt.
The permanent collection of the museum is on the lower level, while the upper floors are dedicated to rotating exhibits. Those exhibits were very family-friendly and were labelled in both German and English. Most concerned some aspect of media, although one explored number sequences. My main interest, though was in the permanent collection, which focuses on the PTT service (post telephone and telegraph, not push-to-talk).
One side of the collection is dedicated to the postal system and includes a number of postal wagons and cars, stamps, mailboxes, and so on. Another area focuses on the phone system and includes working demonstrations from several eras, with phones connected to switching racks. When you dial another phone, you can see the mechanical relays in the central exchange spinning and clicking to route the call.
My main interest, of course, was the radio equipment. Their collection does not focus on amateur radio equipment, but on commercial and consumer equipment. They have quite a collection of very early radios, including some developed for telegraphy. Most were commercial units from the 20s onward, including a good collection of war time radios including those in the Volksempfänger series. The radio collection includes some beautifully styled cabinets, both in wood and later materials like bakelite.
Next to the radio equipment is an exhibit of television equipment, which I found at least as interesting as the radio equipment. In particular, they had an impressive collection of very early mechanical television gear. One item that attracted my attention was a helix composed of many thin, long mirror pieces, arranged like a stair case, with the mirrored surface facing outward. It was mounted on a motor and some other control gearing. This device was descriptively labeled “Spiegelschrauben” (mirror screw). It took me a while to get through museum’s description of the device, as descriptions in this part of the museum were written only in German. The bottom line is that this device provided the raster scan for an early television receiver by the company TeKaDa (from die Süddeutsche Telefon- Apparate-, Kabel- und Drahtwerke A.G — which through a series of corporate mergers and acquisitions eventually was acquired by AT&T, now Lucent Technologies). At the time, work was also progressing on cathode ray tubes, but it was difficult to manufacture tubes with a large surface area and to produce as bright an image on a CRT. Peter Yanczer’s website has a good description. The museum has a number of other early television devices including parts from a Nipkow disc system and Vladimir Zworkin’s iconoscope.
A significant part of the display is given over to telegraphy, both cable and radio. A full high-power spark gap station set into a luxurious wooden desk with porcelain insulators, bright copper coils and brass fittings was a real work of art. However, I did note that the key was not far from some very high voltage junctions (for that matter, the contacts on the key itself probably had a few hundred volts running through them. Operator, beware). Of course, there were obligatory displays on Marconi and the Titanic. A lot of the exhibit was given over to commercial telegraphy, both for railway and general communication. Aside from keys, thumpers, and ticker tape units, there were a number of inventions that would either take telegraph key or keyboard input and transmit a message along a wire. These were not quite teletypes; the message would display letter by letter, usually with a mechanical pointer.
Extending from the telegraph exhibit were collections on radio and landline teletype as well as facsimile machines. One corner is also devoted to the enigma machines of World War II, which includes mention of the work done at Bletchley Park. I had expected to find some Feld Hellscreiber equipment, but I did not see one in the museum’s collection.
The museum is well worth the 3€ price of admission, and if I’m in town again earlier in the day, I’d like to stop in on the amateur station.
As for Namibia, this conference came up quickly. I did make an attempt to contact some hams in Namibia and their IARU affiliate, but was unsuccessful. I’m sure I’ll be back here at some point and with more lead time, so hopefully I’ll get on the air on the next trip.