Philips 819 line TV receiver.

[peter_scott]

Apparently France starting transmissions on 455 lines in 1937 but when the Germans invaded they converted the Eiffel Tour to their 441 standard that I assume was the same as the picture in post #14.

I think the Germans only started using that 441 standard in 1939 so just when the extra board pulses came in I really don't know.

Peter

[FERNSEH]

I believe the reason why the 819 line system had only one broad frame sync pulse is because the multi-pulse frame sync train is an RCA patent. The Marconi-EMI 405 line system has the long serrated frame pulse because EMI was an RCA affiliate.
That's why the Baird 240/25 system had only one long frame sync pulse. BTL didn't have access to certain patents.

DFWB.

DFWB.

[FERNSEH]

Originally Posted by peter_scott

I think the Germans only started using that 441 standard in 1939 so just when the extra board pulses came in I really don't know.

I did read somewhere that by 1939 the German 441 line system had the long serrated frame pulse and equalising pulses.

DFWB.

[Synchrodyne]

Originally Posted by Jac

I agree with Peter that there could just be the wrong sync signals from the Aurora. Or the standard changed.

For tracking the changes in the analogue TV transmission standards over the years, the pertinent reports from the CCIR Plenary meetings from 1951 onwards may be useful. They are available on line, with a good starting point for a search being here: https://www.itu.int/en/history/Pages...ssemblies.aspx. One has to figure out which document contains the desired report, sometimes simply by looking through long .pdf documents.

I have found and extracted quite a few of the pertinent reports. This spreadsheet gives an overview as to what is available year-by-year:

TV Systems - CCIR Reports.xlsx

From a quick glance, it looks as if the positioning of the system E field pulse could have been changed between 1953 and 1956, so I have attached those two reports.

CCIR 1953 London Report 35 TV Systems.pdf CCIR 1956 Warssaw Report 83 TV Systems.pdf


Cheers,

[Synchrodyne]

Originally Posted by FERNSEH

The 441 line system transmitted from the Eiffel Tower has like the 405 line system eight broad frame sync pulses. Like the 405 line system 385 lines carry the picture information. According to the service documentation for the Philips TF390A TV receiver the "d'effacement des signaux de vision" is 28 lines per picture field, approximately 25mS. (The 405 field blanking period is 1.4mS. =14 lines per picture field.)

That Philips documentation for the TF390A seems to be the best available for the French 441-line system details. At least I haven't found anything better, and information on it is generally scarce.


Cheers,

[Synchrodyne]

Originally Posted by FERNSEH

Attachments show the Philips valve position chart and the RF and IF amplifiers in an earlier 819 line receiver, a 17" HMV single channel model made about 1954.

The EBF89 in the Philips appears to be an unusual type in a TV receiver. My guess is that it could be the final sound (AM) IF, demodulator and AGC rectifier. If so, then evidently that valve, designed primarily for HF work, performed well enough at the standard system E SIF of 39.2 MHz, which is likely what was used.

In the Ekco, the use of an ECC81 pair in the front end looks to have been straight out of Philips Book IIIC. Do you know what the IF is? That would have been before the standard VIF of 28.05 MHz came about.


Cheers,

[German Dalek]

Originally Posted by peter_scott

Apparently France starting transmissions on 455 lines in 1937 but when the Germans invaded they converted the Eiffel Tour to their 441 standard that I assume was the same as the picture in post #14.

I think the Germans only started using that 441 standard in 1939 so just when the extra board pulses came in I really don't know.

Morning Peter,
No, 441 lines was since March 1935 or before in operation, during the Olympic games 1936 Television became popular.
Germany had the first regular TV service in the world:
https://www.youtube.com/watch?v=VLDcA51lKqA

The first really good working TV sets were made in 1934.

Regards,
SIXMILLION DOLLARMAN

[Jac]

The German 441 line standard found in a German 1939 book.

Jac

[FERNSEH]

German Dalek wrote: "No, 441 lines was since March 1935 or before in operation, during the Olympic games 1936 Television became popular."

Surely the 1935 TV transmission standard in Germany was the 180line 25 FPS system which was similar in some respects to the Baird 240/25 system?

DFWB.

[FERNSEH]

Jac wrote: The German 441 line standard found in a German 1939 book.
Note the single broad frame pulse and the picture blanking period of only eleven lines, approximately 1millisecond.
DFWB.

[Jac]

Originally Posted by FERNSEH

Surely the 1935 TV transmission standard in Germany was the 180line 25 FPS which was system similar in some respects to the Baird 240/25 system?
DFWB.

That's correct David.
It was 180 line 25 FPS.
See attached photo of a part of an original Telefunken publication.

Jac

[peter_scott]

Originally Posted by German Dalek

No, 441 lines was since March 1935 or before in operation, during the Olympic games 1936 Television became popular.

Good Morning GD,

As David and Jac have suggested I believe the cameras used at the 1936 Olympics were the massive electronic camera that used a technology similar to the Farnsworth camera (hence the need for the massive lens) and the intermediate film camera and both operated 180 line 25 Hz non-interlaced (i.e. flickering like Baird's 240 line system.)

http://www.earlytelevision.org/olympics_1936.html

In fairness to German technology I believe Dieckmann & Hell patented a camera in 1925 that prevented Farnsworth from getting patent rights in Europe for his design.

Peter

[FERNSEH]

"See attached photo of a part of an original Telefunken publication." Jac.


The second attachment describes exactly a photo cell mosaic of a Farnsworth camera.
"uber dieser kuenstliche Netzhaut und reizt jedem Sehnerv, __die winzig kleinen Fotozellen"
Seems to translate that each activated tiny photo cell acts like a capacitor and discharges into a load resistor.

Not the storage principle of the Iconoscope.

DFWB.

[peter_scott]

Originally Posted by peter_scott

As David and Jac have suggested I believe the cameras used at the 1936 Olympics were the massive electronic camera that used a technology similar to the Farnsworth camera (hence the need for the massive lens) and the intermediate

Sorry, my mistake the massive Fernsehkanone were iconoscope cameras. The Farnsworth type that was used was much smaller but I would still suggest that only one line standard was used throughout and that was 180/25 non-interlaced.

https://de.wikipedia.org/wiki/Ikonoskop

https://youtu.be/We5zJVo-5XA

Ignore the Youtube inappropriate content warning.

Peter

[Jac]

From Archiv für das Post- und Fernmeldewesen, 37. Jahrgang Nr. 3: see attachment.

Jac

[Pieter H]

Apologies for entering so late into the discussion, but want to go back to the orginal question: this is almost certainly the Philips TF1786, one of the very last sets of what I call the bigger TX1410 generation. See here.
Attached a valve diagram of the TF1786, which shows both the correct picture tube and tuner valves, so seems to confirm. This was clearly a cost down version of the "regular" TF1757 from 1956, with 24 valves in total, whereas this version only has 18. As suggested this was mainly achieved at the expense of video bandwidth, although there were also three valves saved in the power supply. You can still find a lot about this set on French forums.

The tuner must then have been the FD 090 78 (PCC84 & PCF80, square box, 28.05MHz VIF, 39,2MHz SIF, 12 channels F2-F12), can you confirm that? (a close-up picture of the tuner label would be nice).

Last question from Synchrodyne: the EBF80 was used as IF amplifier and sound AM demodulator. From 1953 to 1958 this was a standard valve in all Philips sets, often used twice, mainly in the sound IF.

Cheers, Pieter

[FERNSEH]

Good evening Pieter,
There is only one label on the Philips tuner and it shows the serial number of the unit.
In fact one of the reasons why the owner brought the set to the workshop was to have the tuner repaired.
Later on I'll determine the sound and vision intermediate frequencies and report my findings.

DFWB.

[FERNSEH]

Pieter H wrote: "The tuner must then have been the FD 090 78 (PCC84 & PCF80, square box, 28.05MHz VIF, 39,2MHz SIF, 12 channels F2-F12), can you confirm that? (a close-up picture of the tuner label would be nice)."


The sound IF is indeed 39.2Mhz and the vision IF 28.5Mhz.

The channel F2 coils are present and I assume for F8 and F8A the same coils are employed.

DFWB.

[rogerdup]

Hello Everybody,
I enter the discussion to put some infos about the 1935 TV era in France. It is interesting to notice that, meanwhile Barthelemy and La Compagnie des Compteurs in Paris began to broadcast 180 lines with a mechanical marvelous
nipkow disc machine in december parallel with the 60 lines cam, the german had the iconoscope ready for broadcast 180 lines and then 441 lines. This was ok for the 1936 olympic games..

Have a good week all of you !
Roger

[peter_scott]

The German 441 line stuff doesn't appear until late 1937. There was some dabbling with 375 line after Telefunken bought the rights to RCA iconoscope technology but I think it's true to say that all the 1936 Olympic television was 180 line as the public viewing rooms were not equipped for any higher standard.

Peter