In article , Uncle Peter wrote:
On Sun, 20 Apr 2014 08:35:31 +0100, charles
wrote:

In article , Uncle Peter wrote:
On Sat, 19 Apr 2014 23:18:20 +0100, John Williamson
wrote:

On 19/04/2014 23:01, Uncle Peter wrote:
On Sat, 19 Apr 2014 22:57:50 +0100, John Williamson
wrote:

On 19/04/2014 21:43, Uncle Peter wrote:
On Sat, 19 Apr 2014 20:58:40 +0100, John Williamson
wrote:

On 19/04/2014 20:48, Uncle Peter wrote:

The same way as they did after they got rid of the mains lock.

The video signals were locked to the mains reference in the
studio and the receiver locked its internal signals to the
broadcast reference.

I see. So the locking in the studio was so the cameras didn't
show flicker on lighting? Or couldn't they just use DC lighting?

As the DC would have been obtained by using rectifiers on the
incoming AC, the flicker would have been exactly the same.

Not if the DC was smoothed well.

Do the sums. To adequately smooth the many kilowatts of lighting
used in the average studio in those days would take Farads of
capacitance and many Henrys of inductance. A single lamp could well
be using about 5 kilowatts, and up to a dozen were in use for most
shots.

So what? The percentage cost of the capacitance would be no different
than doing it on a smaller scale.

TC Studio 1 had an installed lighting load of around a quarter of a
megawatt.

And the percentage cost of smoothing the DC for it would be the same as
if it was a quarter of a kilowatt.

Agreed, but it would be a very large sum

But it wasn't a problem, and the lack of use for the studio in
question probably had more to do with the quality of the 525 line
cameras than the lighting flicker.

It was also, IIRC, better to convert from 625 lines PAL to 525 line
NTSC than the other way round.

This has been observed when we saw USA newsfeeds on the BBC.

You weren't seeing degradation introduced by standards conversion, you
were seeing that the incoming pictures weren't very good.

They looked a lot worse than 100 missing lines.

They looked bad when we saw them in the original standard. Nothing to do
with missing lines.

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