Yes indeed, but oblique lighting can make otherwise flat and uniform
surfaces look like a hilly terrain.
I can well remember the problems also with certain home computers like the
Early Spectrums which had less than clean colour outputs where the yellow
looked dirty green with yellow stripes or little crawling bright bits moved
gently around captions and small letters. Mor attention to clean power
supplies would have helpted no end!

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Graham." wrote in message
...
On 27/12/2011 14:11, Brian Gaff wrote:
The correct answer is, no, maybe this tv has a larger than usual
attriction
for dirt.
Not being able to see the picture mentioned, if its a flat screen then
I
have no idedea, but I do recall some sets having a kind of less than
uniform
antoi reflective coating which could eventually become detatched but
usually
in blobs,, but I suppose if someone rubbed it in one place it could have
that sort of effect.
The set I had was made by Sharp I seem to recall.
I bet there are lots of interesting things in store over the years for
plasma and lcd screens....
Brian


It's certainly true that when plasma screens are used to display content
with a high degree of static content the burn-in is not always
recognisable as text or graphics and just looks like dirty streaks.
I often see such screens in motorway service stations.

The picture Bill posted is just of a small Sony wide-screen LCD with
diagonal stripes protected from a window with a nearly closed Venetian
Blind. I suppose he took the picture because it is slightly reminiscent of
herringbone CCI.

Of course, the Venetian Blind analogy is a common one for technicians and
engineers involved with the Phase Alternating Line encoding system.

--

Graham.

%Profound_observation%

Bill Wright wrote:

http://dl.dropbox.com/u/11023364/DSC00549.JPG

Jammy git, there's your summer already, right there!

--
Paul - xxx
"You know, all I wanna do is race .. and all I wanna do is win"
Mark Cavendish, World Champion 2011
BBC Sports Personality of the Year 2011

In message , Wolfgang Schwanke
writes
charles wrote in
:

In article ,
Graham. wrote:
On 27/12/2011 15:20, Graham. wrote:
On 27/12/2011 14:11, Brian Gaff wrote:
The correct answer is, no, maybe this tv has a larger than usual
attriction
for dirt.
Not being able to see the picture mentioned, if its a flat screen
then I have no idedea, but I do recall some sets having a kind of
less than uniform
antoi reflective coating which could eventually become detatched
but usually
in blobs,, but I suppose if someone rubbed it in one place it
could have that sort of effect.
The set I had was made by Sharp I seem to recall.
I bet there are lots of interesting things in store over the years
for plasma and lcd screens....
Brian


It's certainly true that when plasma screens are used to display
content with a high degree of static content the burn-in is not
always recognisable as text or graphics and just looks like dirty
streaks. I often see such screens in motorway service stations.

The picture Bill posted is just of a small Sony wide-screen LCD
with diagonal stripes protected from a window with a nearly closed
Venetian Blind. I suppose he took the picture because it is
slightly reminiscent of herringbone CCI.

Of course, the Venetian Blind analogy is a common one for
technicians and engineers involved with the Phase Alternating Line
encoding system.


Stop the presses, wrong city.
It's Hanover bars isn't? I must be getting old.
Anyone know where the expression comes from? Google just gives me
nightclubs in Germany, New Hampshire and Pennsylvania.


guessing that's where the Telefunken* research labs were based.

* they were the ones who develped PAL, weren't they?

Yes, but legend has it that it was originally pretty much a one man
show of engineer Walter Bruch, at first against the will of his
employer who would have preferred him to do other research instead.

Anyway, I think "Hanover bars" referred to an artefact that only exists
with "Simple PAL" implementations, thus never with any mainstream
consumer sets.

I think that Sonys, because of their non-standard PAL decoder, used to
be prone to Hanover bars. On my 1810UB, if you looked close up, because
alternate lines were slightly different, you sudden became aware that
the line structure was slowly crawling up or down the picture.
--
Ian

On 27/12/2011 21:17, Wolfgang Schwanke wrote:
wrote in
:

In ,
wrote:
On 27/12/2011 15:20, Graham. wrote:
On 27/12/2011 14:11, Brian Gaff wrote:
The correct answer is, no, maybe this tv has a larger than usual
attriction
for dirt.
Not being able to see the picture mentioned, if its a flat screen
then I have no idedea, but I do recall some sets having a kind of
less than uniform
antoi reflective coating which could eventually become detatched
but usually
in blobs,, but I suppose if someone rubbed it in one place it
could have that sort of effect.
The set I had was made by Sharp I seem to recall.
I bet there are lots of interesting things in store over the years
for plasma and lcd screens....
Brian


It's certainly true that when plasma screens are used to display
content with a high degree of static content the burn-in is not
always recognisable as text or graphics and just looks like dirty
streaks. I often see such screens in motorway service stations.

The picture Bill posted is just of a small Sony wide-screen LCD
with diagonal stripes protected from a window with a nearly closed
Venetian Blind. I suppose he took the picture because it is
slightly reminiscent of herringbone CCI.

Of course, the Venetian Blind analogy is a common one for
technicians and engineers involved with the Phase Alternating Line
encoding system.


Stop the presses, wrong city.
It's Hanover bars isn't? I must be getting old.
Anyone know where the expression comes from? Google just gives me
nightclubs in Germany, New Hampshire and Pennsylvania.


guessing that's where the Telefunken* research labs were based.

* they were the ones who develped PAL, weren't they?

Yes, but legend has it that it was originally pretty much a one man
show of engineer Walter Bruch, at first against the will of his
employer who would have preferred him to do other research instead.

Anyway, I think "Hanover bars" referred to an artefact that only exists
with "Simple PAL" implementations, thus never with any mainstream
consumer sets.

You wouldn't see them if the circuitry around the 1H delay line was set
up correctly, but the service manual might well refer to them in the
adjustment procedure.


As for "simple PAL"
http://www.radiomuseum.org/forum/45_... levision.html

Quote
Notable modifications of PAL include:

The simple PAL (“Volks-PAL”) system, which operated without a delay line
and relied on the human eye to average out the phase errors. Flickering
caused by large phase errors was called “Hannover bars” or “Hannover
blinds.” Only one commercial set was built using this system – the Kuba
Porta Color CK211P.

Now I knew that set quite well, my firm used to market it under the
guise of the Granada Colourette I was well aware it was a Simple PAL
chassis (and a heap of crap for several other reasons), but I did not
know it was unique as a production receiver in that respect.

In fact my college text book
Hutson, Geffery H. Colour Television Theory. McGraw-Hill. 1971
does not refer to PAL without appending a -D or -S suffix.
http://www.flickr.com/photos/g3zvt/6...ream/lightbox/


--

Graham.

%Profound_observation%

On Tue, 27 Dec 2011 23:54:00 +0000, Graham. wrote:

The simple PAL (?Volks-PAL?) system, which operated without a delay line
and relied on the human eye to average out the phase errors. Flickering
caused by large phase errors was called ?Hannover bars? or ?Hannover
blinds.? Only one commercial set was built using this system ? the Kuba
Porta Color CK211P.

All decent professional monitors for studio use were PAL-S (and lots had
PAL-D available on a switch).
You *wanted* to see the Hanover bars if there was a phase error, so you
could do something about it before it got transmitted...

On Wed, 28 Dec 2011 17:44:25 GMT, Paul Ratcliffe
wrote:

On Tue, 27 Dec 2011 23:54:00 +0000, Graham. wrote:

The simple PAL (?Volks-PAL?) system, which operated without a delay line
and relied on the human eye to average out the phase errors. Flickering
caused by large phase errors was called ?Hannover bars? or ?Hannover
blinds.? Only one commercial set was built using this system ? the Kuba
Porta Color CK211P.

All decent professional monitors for studio use were PAL-S (and lots had
PAL-D available on a switch).
You *wanted* to see the Hanover bars if there was a phase error, so you
could do something about it before it got transmitted...

That's logical. I suppose you also wouldn't want burst referenced ACC
as it would mask dodgy line equalization.

Of course you would also have vector and waveform scopes.


--
%Profound_observation%