Terry Casey wrote:

In article ,
says...

David Looser wrote:

"Michael A. Terrell" wrote in message
m...

"Geoffrey S. Mendelson" wrote:

hwh wrote:
On 2/5/12 7:04 PM, J. P. Gilliver (John) wrote:
But you've got to remember that this is the country that kept 405-line
going for, I think, longer after 625 started than it had been going
before that.

Erm, 405 started before the war and was alone until 1964? Then it
continued for another 20 years?

Someone said the last two years of 405 line signals were generated by an
unusal
method, I think the word they used was "endearing". What was it?

BTW, the BBC shut down TV broadcasts in for World War II, and resumed
them at the exact point in the same broadcast after the war. :-)


That's very easy to do with film. I should know. I loaded and ran
truckloads of 16 mm film on a pair of RCA TP66 projectors in the '70s.

I'm sure it is, but as we've already established that the "exact point in
the same broadcast" bit isn't true its not relevant.

The myth that the engineers simply ceased transmission half-way through a
programme and left the station like a sort of Mary Celeste has been
widespread, but it is a myth. In fact there was an orderly shut down and the
film in the machines would have been rewound and put into storage before the
staff left. It would have been 35mm film (the BBC didn't have facilities for
transmitting from 16mm film pre-war) and thus on nitrate stock. NOT putting
it into proper storage would have constituted a fire hazard and been in
contravention of fire regulations.


It still would have been no problem to load and start it at exactly
the same frame, if they had wanted to.

All hypothetical. As David said earlier, it is a myth that transmission
was cut in the middle of the cartoon. Station logs exist that say
different.

Another myth is that the Television Service resumed in 1946 with the
same cartoon. It didn't!

The cartoon WAS repeated that day - but it wasn't the first programme.


Does it matter? Were you alive to see it, and in their service
area? I wasn't and I wasn't. I was a TV broadcast engineer at three US
TV stations from the early '70s to the late '80s. I started with
monochrome and film, and ended up with 1" Sony color VTRS & RCA TK46A
cameras feeding a 5 MW EIRP antenna 1700+ feet AAT.


--
You can't have a sense of humor, if you have no sense.

"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:

They were a dollar. This isn't the same as what I saw, but it will
give you some idea:
http://i00.i.aliimg.com/photo/v0/255041326/DZ_909A_6_way_power_outlet_with.jpg
since the meter was next to the power switch and cord.

That's what we'd call a trailing socket. To be used with an extension
lead. I thought you meant permanently installed sockets. But perhaps you
can't tell the difference.



Perhaps you just like to start fights. We wanted to use Wiremold
Plugmold type steel power strips made for relay racks, but the ESA
wanted individual outlets mounted on metal boxes inside the racks which
wasted a lot of space so we used what they shipped us.


It look like it would also accept other than the UK 13 amp plug - which is
why some tourists might buy it. It doesn't conform to UK regs.


I never said it did. That's why I thought that it was funny to see
them buy a bunch of them, and walk away like they had won a huge prize.


--
You can't have a sense of humor, if you have no sense.

In article , Michael A.
Terrell wrote:



They were a dollar. This isn't the same as what I saw, but it will
give you some idea:
http://i00.i.aliimg.com/photo/v0/255041326/DZ_909A_6_way_power_outlet_with.jpg
since the meter was next to the power switch and cord.

as someone has said, must have been designe for the Hong Kong market.

--
From KT24

Using a RISC OS computer running v5.16

In article ,
Dave Plowman (News) wrote:
In article ,
Mortimer wrote:
Don't/didn't TV studios have some form of backup generators in case of
power failure? At least enough to power VTs and sufficient lighting for
news reports etc, even if not enough to light whole studios?

TV centre had IIRC two feeds from different parts of the grid or whatever
and both failed.

Not quite. The power came in at 33kV (not 132kV gid voltage) as part of a
ring system in West London. There was alsa a reserve feed direct from a
distribution board at Battersea Generating Station. The West London Ring
was fed from the Grid two points, one at Iver in Buckinghamshire and the
other at Battersea. A fault at Iver put the whole load onto the
distribution board at Battersea, which was unable to handle that load.
Something caught fire as a result and there was a total failure, taking out
the reserve feed as well.


I suppose for a first night launch, they'd probably planned live events
that would have taken a lot of power for lighting.

It would have needed a massive generator to fully run TVC. It did have a
small standby one which could manage a continuity announcer.

Think the maximum load at TVC was 11Mw. But Charles will likely remember
better.

Not at that time; once colour came in to 8 studios, with an enormously
increased lighting load then that was quite probable; Studio 1, for
instance, had an installed lighting load of about 0.5MW..

--
From KT24

Using a RISC OS computer running v5.16

"Bill Wright" wrote in message
...
Michael A. Terrell wrote:

Sigh. America was supplying AKA: LENDING planes and other war
materials to help Europe clean up their mess, long before Japan attacked
Pearl Harbor. Is the school system really that bad where you grew up?

Don't forget that the schools in the UK have many teachers who are
socialist and deny the true
history of the 20th century.

You must remember that a lot
of people in the UK are socialists, and they hate the US because that
country has demonstrated
that capitalism works.

Which century and/or planet are you living in Bill? I suggest you wake up
and look around you, the world of the 1930s is over!

David.

In message ,
Terry Casey writes
In article ,
says...

In message , Arny Krueger
writes

"Terry Casey" wrote in message
...


A couple of questions regarding that list:

Why is the HRC channel spacing offset[1] by 300Hz - 6.0003MHz instead of
6MHz?

I don't know.

I recall once specially tweaking a UK 8MHz HRC harmonic comb generator
(to which all of the TV channels were locked). It was a little above (or
was it below?) 8MHz. There was a reason for this, but at the moment, I
can't remember what it was.


One system where this was done was the old BT Westminster system -
probably very useful in an area where I would expect a lot of off-air
reception problems.

Same lot, in the land of the concrete cows and a thousand roundabouts.
;o))

I don't know what offset they used but, as an example, if you alter the
comb to 7.990963855MHz, channel E45 is bang on (663.25MHz) so, if you
centred the five off-airs around this using E41, E43, E45, E47 and E49,
the worst case error will be +/-36kHz from the nominal frequency.

Ah yes. That's certainly one of the reasons for using a weird reference
frequency. I recall that certain systems insisted that the four set-top
bypass channels had to be close to the standard off-air broadcast
channels, because some TV sets would not tune to anything but these.
Almost certainly this is what I was involved in.

But wasn't it at the same place which ingeniously used a not-quite-8MHz
comb reference which was actually derived from one of the UHF off-air
channels? As the headend equipment was largely supplied by the 'other'
company, I doubt if I would have been involved with tinkering with it
(although I'm pretty sure that I did swap one or two of the modulator
SAW filters because of the problems which arose when NICAM started).
Maybe 'my' comb generator was a replacement.
--
Ian

In message , Michael A.
Terrell writes

Terry Casey wrote:

In article ,
says...

David Looser wrote:

"Michael A. Terrell" wrote in message
m...

"Geoffrey S. Mendelson" wrote:

hwh wrote:
On 2/5/12 7:04 PM, J. P. Gilliver (John) wrote:
But you've got to remember that this is the country that
405-line
going for, I think, longer after 625 started than it had been going
before that.

Erm, 405 started before the war and was alone until 1964? Then it
continued for another 20 years?

Someone said the last two years of 405 line signals were
generated by an
unusal
method, I think the word they used was "endearing". What was it?

BTW, the BBC shut down TV broadcasts in for World War II, and resumed
them at the exact point in the same broadcast after the war. :-)


That's very easy to do with film. I should know. I loaded and ran
truckloads of 16 mm film on a pair of RCA TP66 projectors in the '70s.

I'm sure it is, but as we've already established that the "exact point in
the same broadcast" bit isn't true its not relevant.

The myth that the engineers simply ceased transmission half-way through a
programme and left the station like a sort of Mary Celeste has been
widespread, but it is a myth. In fact there was an orderly shut
and the
film in the machines would have been rewound and put into storage
before the
staff left. It would have been 35mm film (the BBC didn't have
facilities for
transmitting from 16mm film pre-war) and thus on nitrate stock.
putting
it into proper storage would have constituted a fire hazard and been in
contravention of fire regulations.


It still would have been no problem to load and start it at exactly
the same frame, if they had wanted to.

All hypothetical. As David said earlier, it is a myth that transmission
was cut in the middle of the cartoon. Station logs exist that say
different.

Another myth is that the Television Service resumed in 1946 with the
same cartoon. It didn't!

The cartoon WAS repeated that day - but it wasn't the first programme.


Does it matter? Were you alive to see it, and in their service
area? I wasn't and I wasn't. I was a TV broadcast engineer at three US
TV stations from the early '70s to the late '80s. I started with
monochrome and film, and ended up with 1" Sony color VTRS & RCA TK46A
cameras feeding a 5 MW EIRP antenna 1700+ feet AAT.

I'm sure that that the point being made was that despite all that had
happened to Britain since 1939, we were now picking up the pieces,
continuing where we had left off, and getting back to business as usual.
Even if it didn't quite happen as reported, there is no doubt that the
popular version of the story would have been good for moral.
--
Ian

charles wrote:
In article , Michael A.
Terrell wrote:



They were a dollar. This isn't the same as what I saw, but it will
give you some idea:
http://i00.i.aliimg.com/photo/v0/255041326/DZ_909A_6_way_power_outlet_with.jpg
since the meter was next to the power switch and cord.

as someone has said, must have been designe for the Hong Kong market.

You also loads of those for sale in electronics stores in the UAE area.

Many 'wall warts' and mobile phone chargers sold in the UAE, Qatar, and
Bahrian have 'Euro' style power pins on them, not UK 13A types, so there's
always the requirement to be able to stuff them into a UK style socket.
Crap that like fits the bill perfectly.



--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

In message , Bill Wright
writes
Michael A. Terrell wrote:


Do you know that the channel combiners in a CATV head end
were wired in odd and even banks, on separate groups to prevent IMD
caused in the passive mixing?

Even now if we use passive filters to combine channels we try to
arrange the filters as follows (for example)
Filter 1: 21, 25, 29, 33 etc
Filter 2: 22, 26, 30, 34 etc
Filter 3: 23, 27, 31, 35 etc
Filter 4: 24, 28, 32, 36 etc
The filter outputs are combined using passive combiners. The idea is to
prevent interactivity between adjacent channel filters.

Ah but, unless they really have to, most large cable TV networks don't
use filter combiners. This keeps the whole of the headend combining
system wideband. Of course, you can only do this if the modulators are
themselves sufficiently clean in respect of out-of-channel unwanted
signals and noise.

Normally, the losses associated with wideband combining are not a
problem. At least one manufacturer made a purpose-made 8-port (and later
a 16-port) combiner, with insertion losses of around 20 and 24dB
respectively. They were designed specifically to provide high isolation
between input ports. A 48-channel headend could be made using four
16-port combiners followed by a standard 4-way turned-around splitter,
so the total loss was around 28dB. As the modulator outputs were around
60dBmV, the combined spectrum level was 32dB - which was more than
enough to allow splitting to provide multiple feeds for the inputs of
individual trunk-line launch amplifiers.

Of course, there are also losses in the interconnecting cables, in-line
injection points for test signals, monitor points etc, so if required, a
special low-distortion level-raising post-amplifier might be used to
ensure that plenty of signal was available. The last thing you want in
large cable TV headends is to be scraping the barrel for signal level.
--
Ian

In message , charles
writes
In article , Michael A.
Terrell wrote:



They were a dollar. This isn't the same as what I saw, but it will
give you some idea:

http://i00.i.aliimg.com/photo/v0/255..._power_outlet_
with.jpg
since the meter was next to the power switch and cord.

as someone has said, must have been designe for the Hong Kong market.

If it could be used on a variety of voltages (120V, 200V - in Hong Kong,
220) and 230/240V), that meter could be extremely useful.
--
Ian