Fernsehen in Holland - Niederlande
Sendungen im Band I gemäß CCIR 625 Norm B aus Lopik und Eindhoven. (FT Mai 10/1951)
Eine Gerätebeschreibung und noch viel mehr:
Der Philips 17TX 170A ein Zeitzeuge für das fernsehtechnisch geteilte Westeuropa der 1950er Jahre.
Die Niederlande - Der Philips 567 Zeilen Standard (1948)
The Netherlands with their Philips 567 line project
Philips-Niederlande – Die 567 Zeilen PragmatikerAls bisher weitgehend unbekannter, jedoch interessanter Lösungsansatz hinsichtlich einer besseren Fernsehnorm erweist sich der auch praktisch vorgeführte Vorschlag des international tätigen Unternehmens Philips in Holland: 1948 war deren Ansatz, das amerikanische 6 MHz Kanalraster als Maß der Dinge zu nennen, was Angesichts der noch bevorstehenden Frequenzknappheit in Europa auch einen sehr sinnvollen Lösungsweg dargestellt hätte: Die Rechnung lautet: Die rund 4,2 MHz mögliche Videobandbreite der 525/60 Norm innerhalb des 6 MHz Kanalrasters sind auf die 50 Halbbilder umzurechnen: 4,2MHz bei 30 Vollbildern ergeben ~280.000 Bildelemente/Pixel pro Vollbild. Bei rund 485 aktiven Zeilen und einem 4:3 Bildseitenverhältnis des amerikanischen Systems ergibt die Umrechnung eine vertikale brutto Zeilenzahl von 567 die sich aus der Einsparung der Übermittlung von 5 Vollbildern pro Sekunde im europäischen 50 Hz System ergibt. Dazu der Pressetext aus dem österreichischen Magazin „Funktechnik“ Heft 2 1948: http://www.scheida.at/scheida/TV_SEITE/philips_48_I.jpg http://www.scheida.at/scheida/TV_SEITE/philips_48_II.jpg 2 Jahre später, im Sommer 1950 war auch dieses Thema bereits Geschichte, wobei nachvollziehbare Begründungen für die Ablehnung (bis jetzt) im Verborgenen blieben. Pressebericht
vom 11.08.1950: (Öst.
Zeitschrift Praktiker) "Fernsehbastlern in Holland wurde kürzlich bekannt gegeben, dass der holländische Fernsehsender für seine Versuchssendungen von 567 auf 625 Zeilen übergegangen ist. Ein solcher Wechsel der Zeilenzahl bedingt natürlich auch eine Änderung der etwa 400 in Betrieb stehenden Fernsehempfänger. Diese Anpassung an die neue Zeilenzahl bereitet keine großen Schwierigkeiten und kann in Holland fast durchwegs von den Besitzern der Geräte selbst durchgeführt werden, da es sich herausgestellt hat, dass 90 Prozent aller in Verwendung stehenden Geräte von Amateuren konstruiert und hergestellt wurden." Für die gerätetechnische Vereinfachung der Empfänger wäre dieser Weg für Philips, einem weltweit agierenden Großkonzern sicher entgegenkommend gewesen. (weltweit baugleiche Tuner u. ZF Kreise etc.) Hier finden Sie eines der damals ca. 148 im Feldtest verwendeten Empfänger: http://www.radiomuseum.org/r/philips_tx594utx_594.html Wie es mit der Fernsehstandardnormierung weiterging lesen Sie hier:
Ein Leser schrieb: Hallo Herr Scheida, |
Dear Dutch Collectors Did you have entrance to detailed informations about the Philips idea of introducing a competitive 567 line system in 1948 to 1950 ? Why was this system canceled and not winning part at the CCIR discussions? Please send me links or informations if you could do that. Thanks Scheida Present informations see: One + Two (This text was in German only)
Jan J. wrotes me:
Hello Wolfgang,
Official reliable information on the
567-line standard is somewhat limited.
Fact is that Philips wanted to propose this
standard seriously within Europe.
From a theoretical (and also practical)
point of view, it looked like the ideal standard at the time. It gave a
good compromise between picture quality and costs. It already contained FM
sound, negative vision modulation, good sync pulses, 3x4 aspect ratio, etc.
And most of all: it looked immediately technically feasible without
excessive product costs.
But in the beginning Philips did very little
to promote it extensively outside NL (we speak of 1947 and early
1948).
In the meantime most countries in Europe
more or less proposed a 625 line standard. The UK had little choice than
to keep the 405 line standard for some time to come, so they did not
really participate actively in the discussions. (France has always
preferred a unique choice for their own purposes and reasons.)
When eventually there was some more effort
from Philips to advertise and promote the 567 line standard, the
other countries unofficially had agreed upon 625 lines.
So for the CCIR committee Philips tried to
use the 567 standard, but very soon saw that other countries would adapt
625 lines.
This would mean a very restricted sales
market for Philips (NL and possibly the Dutch speaking part of B).
Realising the consequences of using 567 lines in isolation and thus not
be able to export television equipment and parts (who would buy from a
baker who does not eat his own (625-line) bread?), Philips rapidly
changed over to 625 lines (1950). And that was, prematurely, the end of
567 lines.
No mass production or regular tv
transmissions (apart from the Eindhoven experimental transmissions in
567 lines) had yet started in NL, so there was no compatiblity problem.
In the mean time Philips was working hard on
the engineering of their first mass produced (625 line) sets: the TX400U
(22 cm CRT) and TX500U (identical chassis, but 31 cm CRT). Only a few
hundred (TX400Us) were ready at the start of the "official" tv
service, broadcasted with Philips equipment and Philips personnel
from the centre of NL. The day of the opening was 2 Oct 1951.
The TX400/500 sets were completely different
from the 567 line experimental ones. Special TV-valves had been
developed in the mean time and all transformers (including the EHT/horizontal
output) were also different.
Of the 567-line sets (already limited
in numbers by it self) probably only a few have been adapted
to the "new" standard. The complete VHF-part should be a
bit different (wider bandwidth) as well as the line output stage. These
567 line sets have been exclusively used by Philips and Philips
engineers for all kind of tests. Some of them were taken home and, after
making reception reports, were again taken back to the labs for further
tests and modifications.
Only experimental broadcasts have taken
place in 567 lines.
The number of different tv sets for this
standard consequently is also limited.
Philips themselves have made 2 different
sets:
* projection TV (6 cm projection tube) with
radio. This was used for tests as well as promotional purposes. You see
the same picture(s) everywhere (405 line version). There is
supposed to have been a 567 as well as a 405 and a 441/445
line version. The aspect ratio of the 405 line version would of course
be different (still 4x5 at that time), but otherwise the external
appearance of all versions was identical.
The 405 line receiver had a completely
different vision chassis than the 567 line version.
* 22 cm direct vision, single channel
(no tuning), table model
In order to give tv some
popularity and allow the (engineering) public to become acquainted with
television, a (Philips) booklet was issued by J. Jager in 1949
("Een experimentele televisieontvanger"). This booklet
described a tv set which could be built from basic parts. Almost all
parts could be bought from Philips dealers and the design used ready
made transformers from Philips. The booklet gave a proposal for the
chassis and building of the tv.
Not many have been built, but it makes
interesting reading material. Most amateurs who actually built a working
tv set chose to use oscilloscope CRTs and make their own designs. Guided
by publications in various magazines.
I am certain I have a (magazine?) article
somewhere, explaining briefly the situation concerning the rapid
changover from the 567 to the 625 line standard (under pressure
from other countries). I'll see if I can find it and then make a
scan for you.
I hope the above helps a bit and sheds some
light over the oscure 567 line period.
Best regards from Eindhoven,
Jac J.
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Updated: 16.06.08