Terrestrial Switchoff - sorry to labour the point but...
 

On Fri, 29 Mar 2013 17:38:05 +0000, Clive wrote:

instead of Hanover Blind all that happened was desaturation of the hue
signal presented to the CRT.

The CRT only deals with RGB. The colour difference signals and luminance
signal are presented to the YUV-RGB matrix.

Terrestrial Switchoff - sorry to labour the point but...
 

In message , Paul Ratcliffe
writes:
On Fri, 29 Mar 2013 17:38:05 +0000, Clive wrote:

instead of Hanover Blind all that happened was desaturation of the hue
signal presented to the CRT.

The CRT only deals with RGB. The colour difference signals and luminance
signal are presented to the YUV-RGB matrix.

That was my first reaction when I read that (and I think it'd be true of
hue), but remember the CRT guns are multi-electrode assemblies. I'm
pretty sure I've heard of sets where the Y signal _is_ applied to one
electrode (in each gun), with colour difference signals (of the Y-R [or
R-Y] type, not B-R or anything) applied to others.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)[email protected]+H+Sh0!:`)DNAf

Imagine what a paradise Earth would be if we'd made the same kinds of advances
in politics as we have in physics. - Andrew Marr in RT, 22-28 September 2012

Terrestrial Switchoff - sorry to labour the point but...
 

On Wed, 3 Apr 2013 01:05:02 +0100, "J. P. Gilliver (John)"
wrote:


instead of Hanover Blind all that happened was desaturation of the hue
signal presented to the CRT.

The CRT only deals with RGB. The colour difference signals and luminance
signal are presented to the YUV-RGB matrix.

That was my first reaction when I read that (and I think it'd be true of
hue), but remember the CRT guns are multi-electrode assemblies. I'm
pretty sure I've heard of sets where the Y signal _is_ applied to one
electrode (in each gun), with colour difference signals (of the Y-R [or
R-Y] type, not B-R or anything) applied to others.

Colour difference drive was used in some early TV sets to minimise the
component count, which was important in the days of thermionic valves.
I think it was luminance to the cathode and colour differences (R-Y,
G-Y and B-Y) to the grids. The G-Y signal was effectively the only one
derived by matrixing anywhere other than in the tube itself.

Matrixing in the tube wasn't quite perfect as grid drive and cathode
drive have slightly different gain & gamma characteristics, and a
contrast control that adjusted luminance gain (which was the usual
practice) would have an effect on saturation as well.

Rod.

Terrestrial Switchoff - sorry to labour the point but...
 

On 4/1/13 11:14 PM, J. P. Gilliver (John) wrote:
In message , Johny B Good
writes:
[]
I still have a 3 inch reel of triple play tape with a recording of a
late night ghost story broadcast by Radio Caroline sometime in 1967.
The tape recorder it was made with has long since been consigned to
Land Fill so I can only audition it at a standard speed where it
either sounds very flat at 1 7/8 ips or quite obviously chipmunky at 3
3/4 ips. My best guess at the original recording speed would be a
surprisingly consistent approximation to 2 1/2 ips, give or take.
[]
I was hoping that there would be a trace of 4 or 5 KHz heterodyne to
help in re-establishing the original speed but of that there was
absolutley no trace (I guess my homebrewed superhet transistor radio
was just too selective to allow such interference). It's going to be a
case of "Adjusting by Ear" when I do get hold of the Round Tuit.

There might be a trace of mains hum (or second or third or fourth
harmonic thereof) - even if your recorder was battery-powered (was it?),
there'd probably be some pickup from the house, or even on the original
signal, which might have been 60 Hz if Caroline used US generators and
equipment

The Mi Amigo (South ship) did, not sure about the North ship off Ramsey.

gr, hwh

Terrestrial Switchoff - sorry to labour the point but...
 

On 4/2/13 3:57 AM, Johny B Good wrote:
If I'm going to detect any constant background signal to use as a cue
to the original speed of the recording, it's most likely to be mains
hum sourced rather than a 9KHz heterodyne.

Probably. You could try to run the tape at double speed to detect it.

[1] I often used to listen to Caroline South in the middle of the day
from the Liverpool area just because I could (nothwithstanding the LO
sideband noise effect on such weak signals as I was picking up on the
built in ferrite rod antenna).


Not bad, must have been after mid 1966 then, when they had a more
powerful signal and better frequency (1187).

gr, hwh

Terrestrial Switchoff - sorry to labour the point but...
 

In message , Paul Ratcliffe
writes
On Fri, 29 Mar 2013 17:38:05 +0000, Clive wrote:
instead of Hanover Blind all that happened was desaturation of the hue
signal presented to the CRT.
The CRT only deals with RGB. The colour difference signals and luminance
signal are presented to the YUV-RGB matrix.
This depends on whether you're using "matrix in the tube" or external
RGB amps.
--
Clive

Terrestrial Switchoff - sorry to labour the point but...
 

In message , "J. P. Gilliver
(John)" writes
In message , Paul Ratcliffe
writes:
On Fri, 29 Mar 2013 17:38:05 +0000, Clive wrote:
instead of Hanover Blind all that happened was desaturation of the hue
signal presented to the CRT.
The CRT only deals with RGB. The colour difference signals and luminance
signal are presented to the YUV-RGB matrix.
That was my first reaction when I read that (and I think it'd be true
of hue), but remember the CRT guns are multi-electrode assemblies. I'm
pretty sure I've heard of sets where the Y signal _is_ applied to one
electrode (in each gun), with colour difference signals (of the Y-R [or
R-Y] type, not B-R or anything) applied to others.
Someone has done a bit of reading, the first sets had the luma to the
base and the colour difference applied to the grids.
--
Clive