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On Tue, 31 Jan 2012 15:32:50 -0500, "Michael A. Terrell"
wrote:

Are you really that stupid, or do you just play a fool on Usenet?
The US National Electrical Code is online. It goes into great detail
about what can and can not be done. Read it, and see if you can learn
anything.


Ahem... the posting to which you reply to deals with UK ring
circuits.
Frankly, anyone who recommmends the practice of wiring as employed in
the US, is having a laugh.
American wiring plus wooden houses... jeez.
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Terry Casey wrote:

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


No, it was a "stealth" airplane.

According to the show, the troops found an experimental stealth airplane
in a hangar in France in the spring of 1945. It had crashed durng a test
flight in February, killing the pilot, but had been restored.

The airplane and parts (possibly for others) were broght back to the US and
stored in a warehouse. Airplane technicains were allowed to
come in and take measurments for a short time.

They then went back to their factory and built a model of it which was used
to test it for it's ability to be detected by 1945 vintage radar. It was
good enough that had it flown, it would not have been detected until
20 miles off the coast of England or the US.

The film also re-enacted a meeting between the head of the Luftwaffe and
the designers of the airplane (which was reliably documented) that they were
told to produce a stealth bomber which could reach New York from (occupied)
France.

At the time of the meeting, it was expected that Germany would have an
atomic bomb in time for a 1946 flight.

http://news.nationalgeographic.com/news/2009/06/090625-hitlers-stealth-fighter-plane.html


Geoff.


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


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

Obviously water boiled with AC is far superior to water boiled with DC.
Alternating current jiggles the molecules up more.


Nothing beats the taste of tea made from water boiled over an old
fashioned
wood fire.


I'm not that much into water that smells of smoke.

Perhaps you are talking about a new fashioned wood fire that is built in a
stove, and thus the smoke is separated from the water.


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"J G Miller" wrote in message
...

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


While most of this pollution happened during the cold war, the place was
originally built to deal with Japan and Germany. In that was, the perceived
need was to build weapons of asymmetrical annihilation before the other guys
did.

In the judgment of history, Einstein vastly underestimated the morality of
the atomic scientists that remained in Germany or at least their ability to
resist Hitler. I don't think that anybody in the west had much of a clue
about what the atomic scientists of Japan could do.


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"Mike Tomlinson" wrote in message
...
In article , David Looser
writes


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.


Wouldn't surprise me, seeing the average American's knowledge of
geography. A very insular country.


The average American's knowledge of geography is not that bad.

IME Europeans vastly underestimate the size of the US. Merely keeping track
of it is equivalent to keeping track of Europe and a big chunk of Asia.

I remember working with a French guy who flew from France to San Diego. His
reaction to the experience was that the flight from Europe to New York was
about the same as his flight from New York to Texas (Dallas), and then he
was only about half way to San Diego. The distances don't quite support his
perceptions, but the flight times including waiting for flights, baggage and
the like, do.




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

snip

Looking back in hindsight, it would have been very likely that if Europe
was
not invaded in 1994, by 1946 the Luftwaffe would of had a jet engine
bomber that was undetectable until 20 miles of the coast, able to
fly to New York and an atomic bomb to drop from it.


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


No, there was also a super bomber based on conventional technology:

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

"The most promising proposals were based on conventional principles of
aircraft design and would have yielded aircraft very similar in
configuration and capability to the Allied heavy bombers of the day..."

IOW, all they had to do is build something between the B17 and the B29.



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

Arny Krueger wrote:

"Peter Larsen" wrote in message
k...
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.



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"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.


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

"Geoffrey S. Mendelson" wrote:

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.


Those '60s TVs worked fine on CATV, with no open channels.


CATV in those days often involved "Cable Converter Boxes" which used the TV
as an IF strip.

Even sets from the '50s work well that way.


IME, the early 50s TVs were better made than their sequels in the late 50s
and 60s. The picture tubes and sweep circuits got larger but the RF, IF and
video circuits were "simplified".

Early CATV was simply 12 VHF channels
deilivered to the TV at 0 dBm to +5 dBm.


Some super cheap sets with a
single IF stage and no RF stage didn't work well, but they were the
floor sweepings of the industry and intended for markets where there was
only one or two stations.


I don't know of any TVs with only 1 IF stage for video.

'Madman' Earl Muntz made some real crap.


Even his stripped-back products had 3 (6AU6) video IF stages. If memory
serves, they may have had only 1 IF stage for sound, but with intercarrier
sound, that's not a fair comparison.

By the late 60s a number of mainstream manufacturers were building sets that
were influenced by Muntz.


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"Mike Tomlinson" wrote in message
...
In article , Andy
Burns writes

No, the phases are *NOT* brown, black & black, they are brown, black and
grey - with blue as neutral.


I refer you to the photo I posted a link to elsewhere.

You seem to think that your photos prove something, they do not beyond what
colours were used in one Spanish installation. If you want to know what the
harmonised colours actually are go and read the documents!

David.




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In article , David Looser
writes

You seem to think that your photos prove something,


Yes, they prove that the installation was done with brown/black/black.
You seemed to have difficulty believing me, which is why I posted a
photo.

You said in an earlier post "I guess the installers simply didn't have
any grey cable" which means you thought the cables were single,
individual cables. I merely pointed out that they were not, but were in
in an armoured outer jacket.

I'm fine that the harmonised colours are brown/black/grey, just saying
that I know of installations - note the plural - where they are not.

Take a chill pill, ffs.

--
(\__/)
(='.'=)
(")_(")
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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?

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

[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

--

Terry
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In article ,
says...

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

says...

snip

Looking back in hindsight, it would have been very likely that if Europe
was
not invaded in 1994, by 1946 the Luftwaffe would of had a jet engine
bomber that was undetectable until 20 miles of the coast, able to
fly to New York and an atomic bomb to drop from it.


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


No, there was also a super bomber based on conventional technology:

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

"The most promising proposals were based on conventional principles of
aircraft design and would have yielded aircraft very similar in
configuration and capability to the Allied heavy bombers of the day..."


Which conflicts with the idea of a stealth bomber ...

--

Terry


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"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.

It was rather a pathetic attempt which should be filed in the "it would
have been better if they hadn't bothered" category.

I don't know what the viewers (if there were any left!) made of it at
the time but, when I saw the film it generated some laughter - possibly
out of pity - from some of the audience.

I entirely agree. Its the most appallingly amateurish thing imaginable. I
particularly like the fact that there is total silence for the first minute
or so and then, at the end of the bulletin, the newsreader says that the
bulletin will be repeated in one minute's time as "I gather nobody could
hear me". So the loss of sound was at the transmitting end. I guess the BBC
were too embarrassed to admit that this news bulletin was actually broadcast
and were quite happy to have the myth that BBC2 only started the next day
gain currency!

David.


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"Mike Tomlinson" wrote in message
...
In article , David Looser
writes

You seem to think that your photos prove something,


Yes, they prove that the installation was done with brown/black/black.
You seemed to have difficulty believing me, which is why I posted a
photo.

I never for one second doubted that you had seen installations done in
brown, black, black. So there was no need to post photos to prove that you
had.

All I said was that the harmonised colours are, and always have been, brown,
black, grey. A fact which you have seemed reluctant to accept.

I'm fine that the harmonised colours are brown/black/grey, just saying
that I know of installations - note the plural - where they are not.

Its entirely possible that brown, black, black was in use in parts of Europe
before the EU-wide harmonised colours were introduced. But they've never
been used here.

Take a chill pill, ffs.

You too :-)

David.


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"Geoffrey S. Mendelson" wrote in message
...
Terry Casey wrote:

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


No, it was a "stealth" airplane.

According to the show, the troops found an experimental stealth airplane
in a hangar in France in the spring of 1945. It had crashed durng a test
flight in February, killing the pilot, but had been restored.

The airplane and parts (possibly for others) were broght back to the US
and
stored in a warehouse. Airplane technicains were allowed to
come in and take measurments for a short time.

They then went back to their factory and built a model of it which was
used
to test it for it's ability to be detected by 1945 vintage radar. It was
good enough that had it flown, it would not have been detected until
20 miles off the coast of England or the US.

The film also re-enacted a meeting between the head of the Luftwaffe and
the designers of the airplane (which was reliably documented) that they
were
told to produce a stealth bomber which could reach New York from
(occupied)
France.

At the time of the meeting, it was expected that Germany would have an
atomic bomb in time for a 1946 flight.

http://news.nationalgeographic.com/news/2009/06/090625-hitlers-stealth-fighter-plane.html


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.


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

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

says...

snip

Looking back in hindsight, it would have been very likely that if
Europe
was
not invaded in 1994, by 1946 the Luftwaffe would of had a jet engine
bomber that was undetectable until 20 miles of the coast, able to
fly to New York and an atomic bomb to drop from it.


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


No, there was also a super bomber based on conventional technology:

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

"The most promising proposals were based on conventional principles of
aircraft design and would have yielded aircraft very similar in
configuration and capability to the Allied heavy bombers of the day..."


Which conflicts with the idea of a stealth bomber ...



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.


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"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.




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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. :-(


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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. :-(


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


All this is pure speculation. The "flying wing" jet fighter flew test
flights, but crashed killing it's pilot. It was a second copy (that never
flew) that was "liberated" to the USA after the war. None of the other
designs for an "Amerika Bomber" made it off the drawing board. How long
would it have taken to develop any design to the point that it could make
the trans-Atlantic flight? How long would it have taken the Nazis to develop
an atomic bomb, bearing in mind that Germany had ceased all work leading to
one back in '42?


David.






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David Looser wrote:

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

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?


--
You can't have a sense of humor, if you have no sense.
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On Thu, 09 Feb 2012 16:30:25 -0500, "Michael A. Terrell"
wrote:


David Looser wrote:

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

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.

d
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Arny Krueger wrote:

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

Arny Krueger wrote:

"Peter Larsen" wrote in message
k...
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'.


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Arny Krueger wrote:

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

"Geoffrey S. Mendelson" wrote:

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.


Those '60s TVs worked fine on CATV, with no open channels.


CATV in those days often involved "Cable Converter Boxes" which used the TV
as an IF strip.

Even sets from the '50s work well that way.


IME, the early 50s TVs were better made than their sequels in the late 50s
and 60s. The picture tubes and sweep circuits got larger but the RF, IF and
video circuits were "simplified".

Early CATV was simply 12 VHF channels
deilivered to the TV at 0 dBm to +5 dBm.


Some super cheap sets with a
single IF stage and no RF stage didn't work well, but they were the
floor sweepings of the industry and intended for markets where there was
only one or two stations.


I don't know of any TVs with only 1 IF stage for video.

'Madman' Earl Muntz made some real crap.


Even his stripped-back products had 3 (6AU6) video IF stages. If memory
serves, they may have had only 1 IF stage for sound, but with intercarrier
sound, that's not a fair comparison.

By the late 60s a number of mainstream manufacturers were building sets that
were influenced by Muntz.


He loved 'Reflex circuits' where a single tube was used at multiple
frqurncies. He was stingy as hell about bypass capacitors and
shielding, as well.


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Arny Krueger wrote:

"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.



Yes, but they would move the local channel to another frequency, if
direct pickup was expected to be a problem. United Video Cablevision in
Cincinnati moved the local channels up one channel,, and numbered the
channels from '1' instead of '2'. Then the original channels were used
for things like the program guide and community bulletin board channels
so that if there was ingression or direct pickup, it was less
noticeable. 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?


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Ian Jackson wrote:

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.



HRC = Harmonically Related Channels. That means that of the carriers
are all multiples of an integer to reduce IMD. I designed and built
some headends in the early '80s.


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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.


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Mike Tomlinson wrote:

Andy writes

No, the phases are *NOT* brown, black& black, they are brown, black and
grey - with blue as neutral.


I refer you to the photo I posted a link to elsewhere.


As others have noted, that installation might be wired in those colours,
but they are not the proper ones, and have not been forced on the UK as
you seem to insist ...

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David Looser wrote:

"Michael A. Terrell" wrote

They had UK outlets, and the 'voltmeter was about 1/2" * 3/4" like the
tiny VU meters that were popular 30 years ago in battery powered tape
recorders.


Now that I *would* like to see a photo of, because I cannot imagine what
they look like from that description. Wherabouts on the socket faceplate is
the meter fitted? You say they have UK outlets, so why are they not
available here? Why would the Chinese make UK sockets and only sell them in
Florida? it makes no sense.

I'm also still puzzled by the claim that "tourists" are buying socket
outlets in flea markets in the US to bring home with them. Socket outlets
are simply far too cheap here to make it worth the bother and expense of
purchasing with foreign currency and then having to pack in one's
weight-limited luggage.



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.


"Look what I've brought you as a souvenir of my holiday in Florida, its a
cheaply made Chinese copy of a BS1363 outlet",

I can't see it somehow!

David.



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"Don Pearce" wrote in message
...
On Thu, 09 Feb 2012 16:30:25 -0500, "Michael A. Terrell"
wrote:


David Looser wrote:

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

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?


Lend-lease was hardly decisive in the 1939-1941 period. The planes that
denied Goering air-superiority over Britain were all British designed and
built and flown overwhelmingly by British pilots (with some from
Czechoslovakia and Poland).

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

And its worth pointing out that the country that did far more than any other
to defeat Nazi Germany was the Soviet Union. Once Hitler made the fatal
mistake of invading the USSR he sealed the fate of his regime. The most
probable outcome had the US not entered the European [1] war would have been
Soviet hegemony over most of Europe, rather than just the Eastern part. The
implications of that for the post-war balance of power are obvious.

[1] The US didn't have the luxury of deciding whether or not to enter the
Pacific war, unless, of course, it chose to cease to have any presence in
the Pacific region.

David.


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"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:
The fact there are multiple grades says much. Better to use an entirely
different connector for arduous duty. Then there is no danger of mixing
them up.


How do you confuse the bright orange medical grade with the ivory
white or brown consumer hardware?


You expect a cleaner or whatever to know the difference? If the plug fits
someone will manage to get it wrong.



You think so? That will get them fired in a hospital. They are
strictly used for medical equipment, and there are plenty of industrial
grade outlets that are installed for other uses. Why would a lazy
janitor pull a heavy machine away from a wall to plug in something, when
there are empty outlets in plain sight, and spaced 10' or less apart?
The vacuums & floor scrubbers have 25 foot cords.

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


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.

David.


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In message , Michael A.
Terrell 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.



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