"Terry Casey" wrote in message
...
In article ,
says...

"Geoffrey S. Mendelson" wrote in message
...

I don't know how well UK sets worked in the 1960's, but US TV sets were
not capable of receiving adjcent channels at one time, so they were not
used. For example, channel 2 was used in New York City, while the
nearest
channel 3 station was in Philadelphia, 90 miles away and too far to be
received without a large antenna.

US analog TV's improved greatly and were generally happy with adjacent
channels for maybe the last 20 years of their lives.

http://www.jneuhaus.com/fccindex/cablech.html

shows cable channels on 6-7 MHz intervals. Adjacent numbered channels
were
used all the time.

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.

Why are the IRC channels offset from broadcast channels (where they
exist) by 12.5kHz?

If memory sserves, two transmitters that are interferring just a little,
produce nasty herringbones if they are running at the same frequency, but
move them apart a tad, and the artifacts are far less objectionable.


[1] UK cable systems mostly use HRC at 8MHz spacing but this is
sometimes varied by a carefully calculated amount so that one block of
UHF channels coincides almost exactly with the broadcast frequencies.
This is done on systems with a by-pass facility to allow a few channels
- usually the local off-airs - to be fed directly to the TV giving the
subscriber direct access from the TV without needing an aerial.

Obviously this block of channels has to be chosen so as not to conflict
with local transmitters, so the offset will vary from system to system
and can't be fixed as in the US table


US cable systems ran on some of the same channels as local broadcasters.

"Terry Casey" wrote in message
...
In article ,
lid says...

[1] UK cable systems mostly use HRC at 8MHz spacing but this is
sometimes varied by a carefully calculated amount so that one block of
UHF channels coincides almost exactly with the broadcast frequencies.
This is done on systems with a by-pass facility to allow a few channels
- usually the local off-airs - to be fed directly to the TV giving the
subscriber direct access from the TV without needing an aerial.

Obviously this block of channels has to be chosen so as not to conflict
with local transmitters, so the offset will vary from system to system
and can't be fixed as in the US table


In case it isn't clear, I should have pointed out that normal cable
reception is via a set top box and, of course, I was referring to
analogue systems ...

The advent of TV sets that could tune the cable channels all by themselves
was a game changer.

In article , David Looser
wrote:
"Terry Casey" wrote

The version of events I described is the one that has been quoted for
over 40 years but I only became aware of that bulletin a couple of
months ago ...

Was it a recording you saw - or a film made at the time?

What I actually saw was a DVD, copied from a video tape. My understanding
is that someone at Kingswood Warren decided to record this "first
programme" off-air, but that the tape then lay forgotten for many years
until it was rediscovered a few years ago. I also understand that the
DVD I saw was a direct copy from the original off-air tape. It's clear
from the picture quality that this was a video-tape recording, not a
film telerecording.

I was working at TV Centre that night. Yes, the Panorama ( a BBC1
programme) team went off to AP (from Lime Grove, which also lost power),
but I was not aware of any attempt to put out BBC2 on air. Not that we'd
have seen it. I also wonder if staff at KW were on site after 5pm. It was
usual to have a general exodus at that time.

Its the most appallingly amateurish thing imaginable.

Since AP was the home of BBC News, why should this have happened. Much
more likely is that someone made "an Entertainment Tape" as a "spoof".

--
From KT24

Using a RISC OS computer running v5.16

In article ,
charles wrote:
I was working at TV Centre that night. Yes, the Panorama ( a BBC1
programme) team went off to AP (from Lime Grove, which also lost power),
but I was not aware of any attempt to put out BBC2 on air. Not that we'd
have seen it. I also wonder if staff at KW were on site after 5pm. It
was usual to have a general exodus at that time.

I was too. On a recording of Dr Findlay's Casebook. The emergency lighting
in the studio died after a few minutes. So we retired to the club for a
pint - I think it was still daylight. After it was obvious the fault
wasn't going to be sorted quickly, we made safe in the studio by torch
light and went home. Strange the way some events stick in the mind.

--
*OK, so what's the speed of dark? *

Dave Plowman London SW
To e-mail, change noise into sound.

Arny Krueger wrote:

One point - this Nazi development (never a practical tool of war) was a
fighter not a bomber. Even in more modern times developing a stealth bomber
was far more difficult and there was a delay of many years between the
first stealth fighter and the first stealth bomber.


How big a bomber and how unpractical a tool of war is a fighter sized
airplane that can't be seen until you are 20 miles off the coast and it's
carrying an atomic bomb?

The distance from the coast to London is 92 miles so it needs to go 112
miles to drop the bomb directly on London. If it was travelling 100 mph,
that would take enough time for it to be noticed and if a fighter got lucky,
it would be shot down visually.

According to the Wikipedia page its top speed was 977 kmh, so it could
go from first contact to ground zero in 11 minutes. Not a lot of time to
find and stop it.

The cargo load of the airplane was about 2000 pounds, about 1/5 of the size
of the Hiroshima and Nagasaki (fat man and little boy) bombs, but that does
not mean that someone could of built an atomic bomb that would fit the weight
critera if one did not care to survive the construction of the bomb and the
flight.

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM
My high blood pressure medicine reduces my midichlorian count. :-(

In article ,
Dave Plowman (News) wrote:
In article ,
charles wrote:
I was working at TV Centre that night. Yes, the Panorama ( a BBC1
programme) team went off to AP (from Lime Grove, which also lost power),
but I was not aware of any attempt to put out BBC2 on air. Not that we'd
have seen it. I also wonder if staff at KW were on site after 5pm. It
was usual to have a general exodus at that time.

I was too. On a recording of Dr Findlay's Casebook. The emergency lighting
in the studio died after a few minutes. So we retired to the club for a
pint - I think it was still daylight.

I possibly saw you there, but I think that by the time I got there the
staff had found candles. The loss of electricity also meant warm beer
since the chillers failed ;-(



After it was obvious the fault wasn't going to be sorted quickly, we made
safe in the studio by torch light and went home. Strange the way some
events stick in the mind.


We staued on for quite some time in case power was restored. By the time I
left power had returned to the south side of Goldhawk Road.

--
From KT24

Using a RISC OS computer running v5.16

Arny Krueger wrote:

Right. It wasn't jet powered, either. The jet engines of the day had service
lives measured in integer hours, which means that a flight from Europe to
the US would be pretty much guaranteed to fail. Fuel economy was miserable
as well.

According to the wikipedia entry (quoted in an earlier post), it had the
speed to make it from Paris to New York in about 6-7 hours.

The jet engines would not of gotten you to New York and back, but it would
of gotten an atomic bomb to New York, which is what was intended.

Geoff.


--
Geoffrey S. Mendelson, N3OWJ/4X1GM
My high blood pressure medicine reduces my midichlorian count. :-(

On Thu, 09 Feb 2012 18:17:34 +0000 (GMT), charles
wrote:

Since AP was the home of BBC News, why should this have happened. Much
more likely is that someone made "an Entertainment Tape" as a "spoof".

You can see it for yourself here. If it's a spoof then the BBC has
presented it in a rather misleading manner.

http://news.bbc.co.uk/1/hi/entertainment/3585041.stm

(The video - in nasty "RealVideo" format - purports to be a recording
exactly as broadcast, although I don't think they had work experience
juniors blindly cropping things to 14:9 back in 1964 so that
particular aspect of the presentation must be discounted.)

--

"charles" wrote in message
...
In article ,
Dave Plowman (News) wrote:
In article ,
charles wrote:
I was working at TV Centre that night. Yes, the Panorama ( a BBC1
programme) team went off to AP (from Lime Grove, which also lost
power),
but I was not aware of any attempt to put out BBC2 on air. Not that
we'd
have seen it. I also wonder if staff at KW were on site after 5pm. It
was usual to have a general exodus at that time.

I was too. On a recording of Dr Findlay's Casebook. The emergency
lighting
in the studio died after a few minutes. So we retired to the club for a
pint - I think it was still daylight.

I possibly saw you there, but I think that by the time I got there the
staff had found candles. The loss of electricity also meant warm beer
since the chillers failed ;-(



After it was obvious the fault wasn't going to be sorted quickly, we made
safe in the studio by torch light and went home. Strange the way some
events stick in the mind.


We staued on for quite some time in case power was restored. By the time
I
left power had returned to the south side of Goldhawk Road.

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?

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

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. However, I have a feeling the reason was a
bit of a red herring. I also remember tweaking another so that one of
UHF cable channels was carefully offset from a local off-air in order to
minimise the visibility of interference patterning (essentially the same
fix as discussed below).

Why are the IRC channels offset from broadcast channels (where they
exist) by 12.5kHz?

If memory sserves, two transmitters that are interferring just a little,
produce nasty herringbones if they are running at the same frequency, but
move them apart a tad, and the artifacts are far less objectionable.

That is almost certainly the reason. Running IRC channels exactly on
frequency can result in unacceptable beat patterns of 0.75 and 1.25MHz
(at least, it did on one European system I was involved with). Moving
all 65 channels HF by 25kHz worked wonders. [This is close to the 5/3 x
15.625kHz offset broadcasters use for off-air 625-line TV.] 12.5kHz will
probably also be a good offset.

[1] UK cable systems mostly use HRC at 8MHz spacing but this is
sometimes varied by a carefully calculated amount so that one block of
UHF channels coincides almost exactly with the broadcast frequencies.
This is done on systems with a by-pass facility to allow a few channels
- usually the local off-airs - to be fed directly to the TV giving the
subscriber direct access from the TV without needing an aerial.

Obviously this block of channels has to be chosen so as not to conflict
with local transmitters, so the offset will vary from system to system

US cable systems ran on some of the same channels as local broadcasters.

These days, UK cable TV systems don't seem to avoid clashing with (or,
at least, partially overlapping) the off-air TV channels (which are all
UHF). Obviously, to prevent interference problems caused by
ingress/egress, sufficient attention has to be paid to the RF-tightness
of the network.
--
Ian