Re: Audio Precision System One Dual Domani Measuirement Systems

[Terry Casey]

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.

 

[Dave Plowman (News)]

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

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.

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.

 

[Ian Jackson]

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 Jackson]

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.

 

[Terry Casey]

In message <[email protected]>, Arny Krueger



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.

They would have to be very unusual TV sets!

It was more likely to be, in the case of Westminster, that, when CATV
systems rarely went above 600MHz, there was nowhere else to put them,
coupled with the fact that the off-air channels were left clear, so it
was convenient utilise to this for the n + 2 arrangement by straddling
the otherwise blank off-air allocation.

A comb of 7.988636364MHz would allow E25, E27, E29 and E31 to be used
with +/-34kHz error (off-airs being 23, 26, 30 & 33)

Of course, this was all long before the Channel 5 debacle - I can't see
a way of interleaving 5 channels around Crystal Palace without involving
the allegedly taboo n + 5 scenario - although I've never seen a problem
with any set I used directly connected to a CATV network

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?

Well, dividing E26 by 64 or E30 by 68 would do the trick. I based my
comb frequency on E28, being the centre channel but an off-air lock
would certainly produce a very stable result, and the offsets would
still be reasonable - +58/-11kHz or +11/-58kHz, depending on choice of
off air channel.

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.

My involvement with the Westminster system was at the time of the DTV
roll-out (or possibly Broadband Internet, I can't remember which) which
coincided with the transfer of the system from BT to ntl, so I never saw
the BT headend but I did see the documentation related to it, complete
with frequency details.

 

[Ian Jackson]

They would have to be very unusual TV sets!

I don't know about 'unusual', but they were a problem. I think there
were only couple of budget brands which only tuned 'spot-on' to the UHF
channels (xxx.25MHz, in 8MHz steps). One might ask indeed "Why would you
need them to do otherwise?" Of course, even our cable set-top boxes
could normally only tune in 125kHz steps, but at least that got you to
within +/-63kHz of the correct frequency - and that was more than close
enough.

It was more likely to be, in the case of Westminster, that, when CATV
systems rarely went above 600MHz, there was nowhere else to put them,
coupled with the fact that the off-air channels were left clear, so it
was convenient utilise to this for the n + 2 arrangement by straddling
the otherwise blank off-air allocation.

A comb of 7.988636364MHz would allow E25, E27, E29 and E31 to be used
with +/-34kHz error (off-airs being 23, 26, 30 & 33)

Of course, this was all long before the Channel 5 debacle - I can't see
a way of interleaving 5 channels around Crystal Palace without involving
the allegedly taboo n + 5 scenario - although I've never seen a problem
with any set I used directly connected to a CATV network

Sets generally seemed to improve a lot in later years. I think that the
change of IF from 39.5MHz to the European 38.9MHz made quite a
difference to N+/- problems. What surprises me is how well some sets
could tolerate having direct inputs of 48+ channels (without them going
through the converter UHF bypass filtering). Certainly, in the olden
days, when faced with more than half a dozen channels, some sets tended
to sag a bit at the knees.

But, as you have said, there used to be so many embargoed channels on a
cable TV system - no adjacent, no N+/-5, no N+/-9, no sums or
differences (with single-ended amplifiers) etc. It's a wonder anyone was
able to get more than two or three channels!

Well, dividing E26 by 64 or E30 by 68 would do the trick. I based my
comb frequency on E28, being the centre channel but an off-air lock
would certainly produce a very stable result, and the offsets would
still be reasonable - +58/-11kHz or +11/-58kHz, depending on choice of
off air channel.

If this is what they did, they could have used either of those channels
from Crystal Palace. Next time I see him, I'll ask the man who will
almost certainly know (if I remember!).

My involvement with the Westminster system was at the time of the DTV
roll-out (or possibly Broadband Internet, I can't remember which) which
coincided with the transfer of the system from BT to ntl, so I never saw
the BT headend but I did see the documentation related to it, complete
with frequency details.

I had little to do with the system in London (I think I only went there
once - underground, near Shepherds Bush IIRC). As I said, my involvement
was among the concrete cows and the roundabouts.

 

[Terry Casey]

I don't know about 'unusual', but they were a problem. I think there
were only couple of budget brands which only tuned 'spot-on' to the UHF
channels (xxx.25MHz, in 8MHz steps). One might ask indeed "Why would you
need them to do otherwise?" Of course, even our cable set-top boxes
could normally only tune in 125kHz steps, but at least that got you to
within +/-63kHz of the correct frequency - and that was more than close
enough.

Apologies - I misread what you wrote!

I thought you wrote "the four set-top bypass channels had to be close to
the LOCAL off-air broadcast channels ..."

I had little to do with the system in London (I think I only went there
once - underground, near Shepherds Bush IIRC).

As I said, I didn't actually visit the headend. All of our equipment was
in a room in the basement of a large block not far from Marble Arch
IIRC. Obviously, the headend couldn't have been far away ...

 

[J. P. Gilliver (John)]

In message <[email protected]>,

Not a bomber - it would have been the A10 rocket.

The A10 was a prosed development of the A4 rocket that was the basis
for the V2 bombs that fell on London (as opposed to the jet engined V1
flying bomb known colloquially as the 'doodlebug' - I think the US term
is buzz-bomb).

To bring this back 'on course' - at least, for uk.tech.broadcast readers
- the A10 rocket is mentioned in this historic article:

http://lakdiva.org/clarke/1945ww/1945ww_oct_305-308.html

And there was a film - 1970s I think - very loosely based on it. If I
saw it now, I'd probably cringe at all sorts of errors in it, but I
remember enjoying it _as a film_, then. I think it might have been
"Operation Crossbow" - CBA to check.

 

[Terry Casey]

In message <[email protected]>,

And there was a film - 1970s I think - very loosely based on it. If I
saw it now, I'd probably cringe at all sorts of errors in it, but I
remember enjoying it _as a film_, then. I think it might have been
"Operation Crossbow" - CBA to check.

1965, I think you'll find. The rocket in the film was supposed to be a
successor to the V2 and I'm sure that it is referred to as the V3 in the
film although, as I later found out, the V3 was a multi-barrelled high
velocity cannon, the site of which I've since visited.

http://en.wikipedia.org/wiki/Fortress_of_Mimoyecques

 

[Ian Jackson]

Or an attempt to raise the moral of the citizens after VE day?

The word, of course, should have been 'morale'. I'm sure that, even
during the war, British morals remained impeccable!

TV broadcasting didn't resume until 1946 - a year after VE Day.

After the war, it took a long time for life in Britain to get back
normal. We were constantly being reminded of austerity and deprivation.
For example, lots of things were rationed, and de-rationing didn't begin
until 1948. I believe that certain things which has escaped rationing
during the war were actually rationed after it ended. I remember sweets
coming 'off the ration' in 1953. Meat was the last, in 1954. In 1951, we
had the Festival of Britain, which was intended to boost both morale and
the economy, and a lavish coronation in 1953.

I expect that the resumption of the TV service with a Mickey Mouse
cartoon also helped to cheer us up - even though, at the time, it would
only be seen by a handful of people in the London area. It could be that
the urban legend which followed was actually more effective than the
broadcast itself.

 

[William Sommerwerck]

"Morality" refers to correct behavior -- not just sexual behavior.

 

[J G Miller]

I'm sure that, even during the war, British morals remained impeccable!

Actually, and not surprisingly, you will find that morals in the
UKofGB&NI deteroriated badly during the war.

In Ipswich in 1943, an increasing number of complaints were received
about air raid shelters being used for “immoral purposes".

 

[Don Pearce]

Actually, and not surprisingly, you will find that morals in the
UKofGB&NI deteroriated badly during the war.

In Ipswich in 1943, an increasing number of complaints were received
about air raid shelters being used for “immoral purposes".

I don't suppose they were any good for much else. And since when was
sex immoral?

d

 

[David Looser]

I don't suppose they were any good for much else. And since when was
sex immoral?

Indeed, I was going to ask J G Miller what he meant by "morals". Its
certainly the case that both World Wars created significant social change
including liberating women from many of the social restrictions that they
had previously suffered from. If J G Miller thinks that giving women more
independence equates to "morals deteriorating badly" then maybe he has a
point!

David.
..

 

[Ian Jackson]

Actually, and not surprisingly, you will find that morals in the
UKofGB&NI deteroriated badly during the war.

In Ipswich in 1943, an increasing number of complaints were received
about air raid shelters being used for “immoral purposes".

And, where still accessible, they probably also continued to be used for
immoral purposes for a long time after the war. And pillboxes.

 

[Terry Casey]

Actually, and not surprisingly, you will find that morals in the
UKofGB&NI deteroriated badly during the war.

In Ipswich in 1943, an increasing number of complaints were received
about air raid shelters being used for ?immoral purposes".

Perhaps Ian forgot the smiley when he wrote that? ;-)

 

[J G Miller]

"Morality" refers to correct behavior -- not just sexual behavior.

Indeed so, and there was a marked increase in behavior which was not
correct during WW2, eg the black market.

 

[J G Miller]

If J G Miller thinks that giving women more independence equates
to "morals deteriorating badly" then maybe he has a point!

Have you stopped beating your wife?

Your attempt at linking two totally unrelated issues is nothing
less than disingenuous and ill-considered.

 

[J G Miller]

Perhaps Ian forgot the smiley when he wrote that? ;-)

Or maybe he was confusing morals and morale?

 

[David Looser]

Have you stopped beating your wife?

Your attempt at linking two totally unrelated issues is nothing
less than disingenuous and ill-considered.

There are *far* from being unrelated! A sexual act takes two, and usually
one is a woman. The social effect of WW2 gave women the freedom to engage in
such sexual behaviour as well as many other freedoms.

It is your attempt to deny the link that is "disingenuous and
ill-considered".

David.