Audio Precision System One Dual Domani Measuirement Systems

[Ian Jackson]

In message <h8udnVQ0wLP9o6nSnZ2dnUVZ_rqdnZ2d@earthlink.com>, Michael A.
Terrell <mike.terrell@earthlink.net> writes

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?

It might have depended on whose combiners you were using.

I hadn't heard about this so, one day (it must have been back in the
80s), I decided to do a quick test to see if it was true. To be honest,
I don't think I saw much difference whichever way I grouped the
channels. From what I remember, with the modulators putting each out
60dBmV, all the intermod products were at least 85dB down, and were
rather difficult to measure quickly. Such low levels of intermod would
have had a negligible impact on the overall system performance.

--
Ian

 

[Terry Casey]

In article <XfCdnRNOVqNkm6nSnZ2dnUVZ_gSdnZ2d@giganews.com>,
arnyk@cocmast.net says...

"Terry Casey" <k.type@example.invalid> wrote in message
news:MPG.299df151e5b042a698971c@news.eternal-september.org...
In article <MPG.299df03b2699ac4898971b@news.eternal-september.org>,
k.type@example.invalid 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.

They are used on the continental cable systems but never have been in
the UK. Possibly because there is much more encrypted subscription
content?

--

Terry

 

[Terry Casey]

In article <gGhWARB4BCNPFwr$@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...

In message <gfmdnaB33LNam6nSnZ2dnUVZ_rGdnZ2d@giganews.com>, Arny Krueger
arnyk@cocmast.net> writes

"Terry Casey" <k.type@example.invalid> wrote in message
news:MPG.299df03b2699ac4898971b@news.eternal-september.org...


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.

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.

--

Terry

 

[Terry Casey]

In article <h8udnVY0wLPRoqnSnZ2dnUVZ_rqdnZ2d@earthlink.com>,
mike.terrell@earthlink.net says...

David Looser wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:ac2dnQvyq4BzZ6_SnZ2dnUVZ_sednZ2d@earthlink.com...

"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.

--

Terry

 

[Dave Plowman (News)]

In article <UaidnQQIJpA-3anSnZ2dnUVZ_hSdnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> 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.

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.

--
*Experience is something you don't get until just after you need it *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Michael A. Terrell]

Don Pearce wrote:

On Thu, 09 Feb 2012 16:30:25 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


David Looser wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:ac2dnQ7yq4B-Za_SnZ2dnUVZ_sednZ2d@earthlink.com...

J G Miller wrote:

All because of the perceived need to produce weapons of mutual
annihilation.


We wouldn't need to do it, if you Europeans would stop starting World
Wars.


According to the history books the US entered WW2 because it was attacked by
the Japanese. It seems that Michael A. Terrell thinks that Japan is in
Europe.


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?

I hope you are not imagining that America did that from anything other
than good, solid self-interst.

Sigh. No, they did it because they know that you Europeans never
could play together without starting stupid fight. What better reason
did we have to stop the production of civilian goods in the US and build
weapons for you losers to kill each other?


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

 

[Michael A. Terrell]

David Looser wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:UaidnQQIJpA-3anSnZ2dnUVZ_hSdnZ2d@earthlink.com...


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.

Right. You started all this by refering to European sockets which had to be
installed in equipment racks. So I naturally assumed that you were talking
about UK specific installation sockets being sold in flea markets in the US.

But now I realise that you are talking about plug-in extention sockets, and
I notice from the photo that that one has "universal" sockets that will
accept US and a variety of European plugs as well as UK ones. Personally I
wouldn't touch one of those with a barge-pole. Those sort of "universal"
sockets rarely make good contact whilst the meter is clearly for show, it
would tell you nothing useful. I'm sure it would not be legal to sell those
here as the sockets appear not to have shutters, which probably explains why
I've not seen one.

I wouldn't touch one, even if I needed the voltmeter.

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

 

[Michael A. Terrell]

Ian Jackson wrote:

In message <h8udnVQ0wLP9o6nSnZ2dnUVZ_rqdnZ2d@earthlink.com>, Michael A.
Terrell <mike.terrell@earthlink.net> writes



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?

It might have depended on whose combiners you were using.

I hadn't heard about this so, one day (it must have been back in the
80s), I decided to do a quick test to see if it was true. To be honest,
I don't think I saw much difference whichever way I grouped the
channels. From what I remember, with the modulators putting each out
60dBmV, all the intermod products were at least 85dB down, and were
rather difficult to measure quickly. Such low levels of intermod would
have had a negligible impact on the overall system performance.

How many channels and at what signal levels did you try it on? We
had seven six port combiners in two groups of eight for a 36 channel
headend. The six outputs were combined in the seventh unit and
amplified before leaving the building. It did help in some
installations, where HSP were used for off air processing and for
stations who would push their character generators to over 100%
modulation from affecting other channels.


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

 

[Michael A. Terrell]

Terry Casey wrote:

In article <h8udnVY0wLPRoqnSnZ2dnUVZ_rqdnZ2d@earthlink.com>,
mike.terrell@earthlink.net says...

David Looser wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:ac2dnQvyq4BzZ6_SnZ2dnUVZ_sednZ2d@earthlink.com...

"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.

 

[Michael A. Terrell]

"Dave Plowman (News)" wrote:

In article <UaidnQQIJpA-3anSnZ2dnUVZ_hSdnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> 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.

 

[Ian Jackson]

In message <MPG.299e71ff4f33530c989721@news.eternal-september.org>,
Terry Casey <k.type@example.invalid> writes

In article <gGhWARB4BCNPFwr$@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...

In message <gfmdnaB33LNam6nSnZ2dnUVZ_rGdnZ2d@giganews.com>, Arny Krueger
arnyk@cocmast.net> writes

"Terry Casey" <k.type@example.invalid> wrote in message
news:MPG.299df03b2699ac4898971b@news.eternal-september.org...


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

 

[Ian Jackson]

In message <dbadnR-QhNwICanSnZ2dnUVZ_vednZ2d@earthlink.com>, Michael A.
Terrell <mike.terrell@earthlink.net> writes

Terry Casey wrote:

In article <h8udnVY0wLPRoqnSnZ2dnUVZ_rqdnZ2d@earthlink.com>,
mike.terrell@earthlink.net says...

David Looser wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:ac2dnQvyq4BzZ6_SnZ2dnUVZ_sednZ2d@earthlink.com...

"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

 

[Terry Casey]

In article <EIl$DMEoyNNPFw$D@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...

In message <MPG.299e71ff4f33530c989721@news.eternal-september.org>,
Terry Casey <k.type@example.invalid> writes
In article <gGhWARB4BCNPFwr$@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...

In message <gfmdnaB33LNam6nSnZ2dnUVZ_rGdnZ2d@giganews.com>, Arny Krueger
arnyk@cocmast.net> writes

"Terry Casey" <k.type@example.invalid> wrote in message
news:MPG.299df03b2699ac4898971b@news.eternal-september.org...


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.

--

Terry

 

[Ian Jackson]

In message <MPG.299f0b2cfc86815c989723@news.eternal-september.org>,
Terry Casey <k.type@example.invalid> writes

In article <EIl$DMEoyNNPFw$D@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...

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!

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!

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.

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!).

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.

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.
--
Ian

 

[Arny Krueger]

<grimly4@gmail.com> wrote in message
news:q5f7j7hb8b019n290u0osd7ilepephrmrc@4ax.com...

American wiring plus wooden houses... jeez.

All things considered it works very well, at a cost in copper.

My estimated death rate in the UK due to all fires was about 0.8 per
100,000 in the last year for which I have reports, and was (2006) and 0.96
in the US (2007)

I have not yet been able to get an exact comparison of death rate due to
structure fires in the same year but US homes are not the death traps that
seems to be suggested above.

US's death rate due to structure fires continues to be declining rapidly for
new buildings every year, of which we are still building quite a few. The UK
is also enjoying improvements in this area, but with slower rates of
improvement and probably lower rates of new construction. Both the UK and
the US show disappointing results for structures built in the 1950s and
1960s.

 

[Arny Krueger]

"Geoffrey S. Mendelson" <gsm@mendelson.com> wrote in message
news:slrnjj8625.n6o.gsm@cable.mendelson.com...

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?

Given the lack of effectiveness of bomb sighting and delivery in those days,
you needed a lot of big bombers to do any strategic damage at all.

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.

I thought we were talking about Germany bombing the US.

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.

I now of no evidence that care taken during construction the shielding of
the bomb while being delivered was making the bombs that big and heavy. I'm
under the impression that most of the gains that were made in minaturizing
atomic bombs had to do with the design of the mechanism.

After all how much size or weight in shielding do you have on an A-Bomb that
you can fire with a mortar or a bazooka?

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

"Other potential delivery methods include artillery shells, mines such as
the Medium Atomic Demolition Munition and the (very odd) Blue Peacock, and
nuclear depth charges, and nuclear torpedoes. An atomic mortar was also
tested. Even an 'Atomic Bazooka' was designed to be used against large
formations of tanks."

More may be known about comparable Russian weapons because of the break down
of the Soviet military:

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

"These devices, "identified as RA-115s (or RA-115-01s for submersible
weapons)" weigh from fifty to sixty pounds."

While the active materials in an A-bomb are radioactive, they aren't all
that radioactive until they become a critical mass.

 

[Arny Krueger]

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:3f-dnSXGvO8VoanSnZ2dnUVZ_qCdnZ2d@earthlink.com...

Arny Krueger wrote:

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:ac2dnQjyq4C-Z6_SnZ2dnUVZ_sednZ2d@earthlink.com...

Arny Krueger wrote:

"Peter Larsen" <digilyd@hotmail.com> wrote in message
news:4f2eedb7$0$56792$edfadb0f@dtext02.news.tele.dk...
Ron wrote:

Surely you remember analogue TV Arny, it's when we had five
channels
of rubbish, now we have 900 channels and it's still rubbish

What's TV?

Something that can actually be enjoyable, useful and even a bit
educational,
managed well.

A capacious 2 channel DVR is a big help.

An internet ready BluRay is better. A lot of free TV via the
internet including classic movies, comedy and Sci-Fi.

We have the hardware for both. After experiencing a hands-on unfettered
comparison of the two for about a year, we kept the DVR and terminated
the
Internet service for the BluRay, but kept the stream of rental BD discs.


The BluRay was a one time investment of $80. Since I already have
broadband, there is no monthly fee. No need for a credit card, or trips
to one of the few remaining video stores, or to try to find something
worth watching in a 'Redbox'.

If you are obtaining current movies for just the cost of broadband, then you
are not paying the usual fees for viewing copyrighted materials. The
morality of that is up to you, but its not a fair comparison.

In the US the usual fee for obtaining a fairly current movie over broadband
is about $5 each. Netflix over broadband is more like $9 per month, but the
catalog is severely limited, both in terms of movies and also TV shows.

Redbox is the price/performance winner around here, and their nearest
machine is within easy driving or biking distance.

 

[Arny Krueger]

"Terry Casey" <k.type@example.invalid> wrote in message
news:MPG.299e6aa2ffcbdf9989720@news.eternal-september.org...

In article <XfCdnRNOVqNkm6nSnZ2dnUVZ_gSdnZ2d@giganews.com>,
arnyk@cocmast.net says...

"Terry Casey" <k.type@example.invalid> wrote in message
news:MPG.299df151e5b042a698971c@news.eternal-september.org...
In article <MPG.299df03b2699ac4898971b@news.eternal-september.org>,
k.type@example.invalid 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.

They are used on the continental cable systems but never have been in
the UK. Possibly because there is much more encrypted subscription
content?

We have TVs that will show encrypted content. They have a slot for a
"Cablecard" which is a decrypter that is supplied by the content provider
(cable company). AFAIK cable company DVRs have two Cablecards inside the
box, and they are available for installation in PCs.

 

[Terry Casey]

In article <oBlkBQUpZQNPFwKg@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...

In message <MPG.299f0b2cfc86815c989723@news.eternal-september.org>,
Terry Casey <k.type@example.invalid> writes
In article <EIl$DMEoyNNPFw$D@g3ohx.demon.co.uk>,
ianREMOVETHISjackson@g3ohx.demon.co.uk says...



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!

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 ...

--

Terry

 

[J. P. Gilliver (John)]

In message <MPG.299dc4ab8a5fc2bb989717@news.eternal-september.org>,
Terry Casey <k.type@example.invalid> writes:
[]

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.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

All I ask is to _prove_ that money can't make me happy.