205-Lines?

[Steve Anderson]

Chaps,

In recent times someone here made passing reference to a 205-line format. Up until that point I had not heard of it before. Does anyone have more information regarding this?

A few stabs at the calculator reveals a required bandwidth at 25fps of around 700kHz, not what I would call 'narrow-bandwidth', more 'medium bandwidth'.

I wouldn't mind having a play around with this in the future.

If anyone has info on a format between 100 and 200 lines I would be interested in that too.

Steve A.

[DrZarkov]

Why 205? I would understand Baird's 240 line system or the German 180 line system (with (1937) or without interlace (1935)). But 205?

[Steve Anderson]

Why 205?

I don't know. I'm sure someone made reference to 205 lines recently, but perhaps it was in a dream.

Steve A.

[KG6KGG]

Hey Gents:

Perhaps your source of information was confused between 405 and 240 line formats.

If no you may want to see what 205 lines would get you. I read that Baird used 240 lines to maintain the image proportions for cinema film used in his intermediate film transfer technology. If you Google that perhaps something will come up. though I have tried and nothing shows up for 205 lines.

Interestingly, if you Google 205 line television one link I saw saw lead to a digital video encoding standard. Sorry I lost the link since I didn't think that it related being from 1993.

Ideas:

1.) If there was a 205 line format it may be the next step down from the Baird 240 line standard that maintains the image proportions for film transfer.

2.) Perhaps 205 lines was a "kludge" between 180 line German standard and 240 line Baird standard? (I also read that Baird had a German subsidiary, for intermediate film transfer technique) Perhaps 205 was an early search for a common format? They were promoting intermediate film transfer in both countries at the time; perhaps for the '36 Berlin Olympics?

[Steve Anderson]

...the German 180 line system with (1937) or without interlace (1935).

So we'll assume that 205 lines was a figment of my (rather boring) imagination. However, the German 180 line system does interest me, any links/sites/data on this? The sites or data can be in German, no problem.

Steve A.

[DrZarkov]

The best I found in the internet is the German Wikipedia about the television transmitter "Paul Nipkow":

http://de.wikipedia.org/wiki/Fernsehsender_Paul_Nipkow

I have to look up more details in books, it will follow soon...

[Steve Anderson]

The best I found in the internet is the German Wikipedia about the television transmitter "Paul Nipkow":

Thanks for that Volker. My German isn't what it used to be but I was able to decode most of it. I haven't used German in thirty years, as it is said...Us it or lose it. Very true.

Anyway, a very interesting read, what I would like is more technical data like sync and blanking, aspect ratio and so on...it must be out there somewhere!

Thanks again.

Steve A.

[DrZarkov]

I found in my collection the book "Das Fernsehen" by Kurt Lipfert from 1938. In that time the transmitter "Paul Nipkow" was transmitting in 441 lines, the transmitter Witzleben still in 180 lines. Information about the 180 line system are spreaded over the whole book, but not in a useful form. I try to collect here everything:

Lines: 180
aspect-ratio: 5:4
frames/sec: 25 non-interlaced
picture-carrier: 1,3 MHz

Transmitter Witzleben: Picture at 6,72 meter
Sound at 7,06 meter
Power: 16 kW
Tower: 135 meter high, enough for a 50 km radius around "Groß-Berlin".

If you like, I can scan in some pictures and scematic drawings of German prewar TV-designs. They are very comparable to Baird's designs, the Fernseh A.G., Farnsworth and Baird were working close together.

Other information: At the studio in Witzleben the Nipkow-disc was stil in use, in a "scanning-room" like Baird used tham or for scanning movies, including the intermediate film system.

The book "Fernsehen - wie es begann" by Dieter Holtschmidt has slightly different information:

The 180 line system started in 1934: picture at 44,3 MHz, sound at 42,5 MHz, bandwidth 500 kHz from a Reichspost test-transmitter. Screen maximum 24x30 cm.
1935: First public TVs.
23. December 1935: start of the transmitter "Paul Nipkow"
15. January 1936: start of official public television service (180 lines). Tvs were available between 1000 and 3000 RM. (A worker earned about 80 Pfennig per hour in that time...)
1936 introduction of interlace, start of test-transmissions with 375 lines.

summer of the same year: XI. olympic games in Berlin were transmitted ini 180 lines, no interlace from the transmitter Witzleben ("Funkturm" at the IFA-area. Still existing.)

1937 15. July: new system with 441 lines officialy introduced.


Very interesting in that book the technical information about the several available TVs: I saw none with 180 lines *and* interlace, but the Loewe FE B from 1935/1936 was switchable from 180 lines/no interlace to 240 lines with interlace, which was the Baird-norm. As I said: the "jewish" Loewe AG worked closely together with Baird. (I think sporadic-E reception of the BBC programme in Berlin would have been possible in the summer, at Youtube there are some interesting films about the reception of London and Berlin in New York in 1938. )

So I think that there never was a regular television service in 180 lines/interlace, it had been used only experimental for a very short time, if it really had been used.

[KG6KGG]

Recently I rented a DVD documentary on pre-war German TV from our Netflix video rental service. Very interesting stuff, I think it was called "Television under the Reich" or something linke that.

Unlike the British, they kept transmitting though '39 to late '44. In later years the broadcasting fare waqs mostly propganda and entertainment for the troops laid-up in holpital.

The regime in power much perfered radio, since even at 180 lines none of them looked good on TV! Radio was much better for speeches and the imagery of the mind.

[DrZarkov]

It's "Television under the Swastika", it was at Youtube, but I'm afraid it has been deleted. I have a copy, but it is 478 Mb. Too much for an upload, not to mention the copyright...
If anybody is interested, I can bring my laptop with me to the convention in Loughborough...

[KG6KGG]

Yes, that was the name of the documentary. It was very interesting.

In comparison you will note that in countries like the USA that did not have a central broadcasting arm of the government (like the BBC) There were many mechanical TV standards. Why, I think here in the USA they had dozens of stations with dozens of incompatible formats. That's why in North American mechanical TV there were Nipkov diskes with several spiral patterns on them for use with eith of 24, 48 or 60 line standards. (See Daven "Tri-Standard)

As an aside the British and Dutch stopped transmitting since they considered the low VHF signals as nice navigational beams for the Luftwafe.

Much of British TV research in the mid 30's was a cover for the development of radar... they wouldn't need those Klystron tubes for microwave ovens. (Also as an aside it was an American navy radio technican in the Pacific war theatre who noticed that the chocolate bar in his pocket melted faster when he was near the radar dish. Later he would invent the microwave oven)

[KG6KGG]

Steve:

I seem to recall the admonition from my mother, and I guess from all mothers in NTSC countries since 1941 of “don’t sit too close to the TV, you will ruin your eyes!”. If you Google the term “Kell Factor” I think it may give you an explanation of effective resolution of a raster scan, at least as far as the television engineers of RCA saw it.

One reads that the first NTSC sets allowed the viewer to make many more adjustments than those produced just a few years later. Usually, they would mess with the picture until they couldn’t see anything. So RCA and the other manufacturers (who all used RCA designed circuits) just preset line width at the factory instead…. I have often heard that Europeans complain of the NTSC picture as being too coarse, then again PAL was standardized in the early 50’s, so give good old NTSC a break. She was to be put to death by government decree tomorrow in favor all HDTV broadcasts, but the new Obama administration extended the death sentence till this summer due to the economy and availability of standards converters for older (non HDTV capable) sets and low income viewers.

In effect, if you can see the line structure of the picture, you are sitting too close to the TV!

[Steve Anderson]

...then again PAL was standardized in the early 50’s, so give good old NTSC a break. In effect, if you can see the line structure of the picture, you are sitting too close to the TV!

Volker thanks for all the data, I assume that the aspect ratio was slightly landscape, correct? I did guestimate the bandwidth required and it agreed with the 500kHz mentioned above. Thanks for the offer to scan further documents but I'll be doing my usual hybrid design using tubes that are still available, I'm not sure if there is a source of German tubes, maybe in Germany but I haven't seen many elsewhere.

Dave, as you probably are aware PAL and NTSC are very closely related, PAL could almost be called 'Son of NTSC'. What confuses a lot of people is the relationship between the number of lines, the colour encoding system used and the frame/field rate. In the studio it is very hard to tell the difference in a side-by-side comparison between 525/60 NTSC and 625/50 PAL at correct viewing distance. The problem occurs on analogue transmission where phase changes occur between the transmitter and receiver.

PAL gets around this by alternating the phase at line rate (simplification here) so a +10° error becomes a -10° error on the next line.Nothing is done about this and it is presented to the CRT (or whatever) as is. The eye and brain integrates this and we get the impression of the correct colour.

There is no technical reason why PAL couldn't be used at 525 lines and NTSC on 625 lines. There is also the choice of sub-carrier frequency, 3.58 or 4.43MHz. There is a reason for these frequencies but I'm not going into that here. Some South American countries do use some odd combinations. NTSC colour was experimented on 405 lines in the UK but was not put into service with the impending change-over to 625 lines.

I'm not even going to mention SECAM, heck I just did!...and as usual I've wandered off-topic!

Steve A.

[DrZarkov]

Yes, of course the TV here was landscape, like the electronic TV in the UK. In Germany never anything but horizontal scanning was ever used. For getting German valves, no problem. Of course you can look at ebay.de for "Röhren" and the common names like Telefunken, Loewe, TeKaDe, Valvo (actually Philips, but also made and used in Germany), AEG. A good source is http://www.jogis-roehrenbude.de/
The name means translated "jogi's valve-shack". The owner of that homepage (Jogi) wrote two books until now, he is kind of a German "valve-pope". (But nicer than Ratzinger...)

[Steve Anderson]

Thanks for that Volker...it's a huge site, I could spend hours in there!

You'll notice I've started a new thread off specifically for the German 180-line system.

Steve A.