Using "Z" Mod on a scope.

[ppppenguin]

That wiki artcicle looks as if it's suffered in translation

Since July 1952 the 441 lines transmitter was no longer broadcasting separate programs, but simply picked up the national network's picture through an 819-441 lines "optical converter" (a 441 lines camera, slightly out of focus, pointed at an 819 lines monitor equipped with an oval spotlight cathode ray tube).

My italics. What on earth do they mean? Do they mean an astigmatic spot (or possible spotwobble) to minimise moire. This is presumably why the 441 camera was out of focus.

[Terry]

If you change spotlight to spot and rearrange the words slightly to read 'an 819 lines monitor equipped with a cathode ray tube with an oval spot'  it makes perfect sense. Well, to me it does, anyway!

You could, of course, change spot to electron beam but that wouldn't then be a direct translation.

[ppppenguin]

Yes, that makes sense. Not sure why they'd use an oval spot and still have to defocus. The other trick is simply to reduce the vertical scan on the monitor until the lines just merge. Then tweak the camera to suit.

On the Northern Line announcements: "The next station is Oval". It's not: https://upload.wikimedia.org/wikipedia/c...ilding.JPG

[Alistair D]

Hi.
The German 180/25p line system has 169 active lines.
The full specs are here: https://en.wikipedia.org/wiki/180-line_t...ion_system

Next thing to do is to construct a larger screened monitor and something not using a green display. Would like to stick with an electrostatic tube about 5-6 inch, any suggestions?

Finding something with anything other than a P31 phosphor will be a bit more difficult. To give you a better idea of what phosphors are available have a look at this site. http://www.bunkerofdoom.com/tubes/crt/cr...search.pdf

One scope with a larger screen is the Telequipment D83. They are very common, inexpensive and quite easy to fix when they go wrong.

One, probably silly, idea I had was to use something along the lines of a Tek 7000 series scope. A very cursory glance implies that one of the Y plugins could be replaced with another timebase module. 

Although the TQ D83 is a modular scope I know for a fact the the timebase module will not connect to the motherboard when pushed into the Y amp bay.

Al 

[Murphyv310]

                               
Thread Revival!!!!
Spurred on by my "Winter Project" I have tried the Sync output on the old Aurora for mechanical systems onto the scope with some success.
The output of the Aurora for mechanical sync is a sine wave to basically lock up the motor, with just a simple clipping circuit reasonable lock can be obtained, even the frame can be held steady, the 1881 chip giving out some rather weak pulses.
The Photos are off screen and from 30 lines to 120 lines, all mechanical, two can be seen rotated due to vertical scanning which as yet I have not tried an XY as yet.

[Murphyv310]

Hi.
The next thing to try is 96 and 90/25p on the modified Bush.
I can get the line TB to run at 2Khz with EHT dropping to 4.5Kv so I'd imagine I would get some results once I've got it to sync up.
I'll post all that on the Winter Project thread though.

[Murphyv310]

More madness in my shed!!!!!
https://youtu.be/PyPzCRatq8I

[peter scott]

That's remarkably good but my goodness I think Test Card F is a rather severe test for Baird 30 line format. You should be giving it something like this (on its side??):



Peter

[Murphyv310]

Good call Peter.
A simpler test pattern would be the idea and I think your attachment will feature on the scope next.
I'm really getting the bug for this, it's really good fun. Having the old aurora is great for these old standards.

[pwdrive]

Nah Trev...what's needed is Z Cars...

Lawrence.