I need to copy a PAL-VHS tape in NTSC format for someone in the US. I
have a Sony VCR which can read tapes in NTSC format and I want to dub
this tape from a second VCR. My first attempt produced a tape which
can be played whether the Sony is in NTSC mode or PAL mode. Have I
succeeded or am I wasting my time?

I appreciate this is off topic here; perhaps someone could point me to
a more appropriate newsgroup if there is no simple answer?

The European and North American TV systems use different standards -- 625/50
and 525/30, respectively. You cannot copy from one to the other without
conversion at some point.

If the tape is PAL, you need a VCR that can output the image in NTSC format
(or something closely approximating it), which you would then copy to a VCR
that records in NTSC format.

If you would tell us more about the VCRs you have (make and model, specific
features), it would be easier to help you.

In article ,
Graz wrote:
I need to copy a PAL-VHS tape in NTSC format for someone in the US. I
have a Sony VCR which can read tapes in NTSC format and I want to dub
this tape from a second VCR. My first attempt produced a tape which
can be played whether the Sony is in NTSC mode or PAL mode. Have I
succeeded or am I wasting my time?

NTSC tapes are usually viewed in the UK by a cludge between the VHS and TV
- the VHS doesn't actually convert them to PAL.

You might be able to do it properly via your PC.

--
*Never miss a good chance to shut up *

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

On Sun, 21 Dec 2008 04:10:47 -0800, "William Sommerwerck"
wrote:

The European and North American TV systems use different standards -- 625/50
and 525/30, respectively. You cannot copy from one to the other without
conversion at some point.

If the tape is PAL, you need a VCR that can output the image in NTSC format
(or something closely approximating it), which you would then copy to a VCR
that records in NTSC format.

If you would tell us more about the VCRs you have (make and model, specific
features), it would be easier to help you.

I think you've answered my question. The source VCR (JVC HR-J470EK)
doesn't have the capability of outputting in NTSC format. The object
VCR has the capability of reading NTSC tapes but probably not
recording them (Sony SLV-F900). So it looks like the idea is a
non-starter.

On Sun, 21 Dec 2008 12:53:56 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Graz wrote:
I need to copy a PAL-VHS tape in NTSC format for someone in the US. I
have a Sony VCR which can read tapes in NTSC format and I want to dub
this tape from a second VCR. My first attempt produced a tape which
can be played whether the Sony is in NTSC mode or PAL mode. Have I
succeeded or am I wasting my time?

NTSC tapes are usually viewed in the UK by a cludge between the VHS and TV
- the VHS doesn't actually convert them to PAL.

Cludge? Is that a technical term? :-)

You might be able to do it properly via your PC.

I'd be interested to know what's involved.

On 21 dic, 16:38, (Graz) wrote:
On Sun, 21 Dec 2008 12:53:56 +0000 (GMT), "Dave Plowman (News)"

wrote:
In article ,
Graz wrote:
I need to copy a PAL-VHS tape in NTSC format for someone in the US. I
have a Sony VCR which can read tapes in NTSC format and I want to dub
this tape from a second VCR. My first attempt produced a tape which
can be played whether the Sony is in NTSC mode or PAL mode. Have I
succeeded or am I wasting my time?

NTSC tapes are usually viewed in the UK by a cludge between the VHS and TV
- the VHS doesn't actually convert them to PAL.

Cludge? Is that a technical term? :-)

You might be able to do it properly via your PC.

I'd be interested to know what's involved.

you will need a vcr which outputs in NTSC 3.58 - not just NTSC 4.43,
WHICH IS USED TO PROVIDE COLOUR ON A PAL tv but is useless for copying
(sorry- caps lock jammed!)
I have a sony SLV-ER7UY which has a switch for both modes, but there
were a number of Uk models offering this. try ebay.

once you get such a machine you just set your pc card and capture
software to ntsc.you can them make a vcd or dvd . I have done this.
-B

On Sun, 21 Dec 2008 15:38:38 GMT, Graz wrote:
On Sun, 21 Dec 2008 "Dave Plowman (News)" wrote:

Cludge? Is that a technical term? :-)

Yes. Spelled wrong. "Kludge", IIANM

In article ,
Graz wrote:
You might be able to do it properly via your PC.

I'd be interested to know what's involved.

A PC should have the processing power required to do a pukka standards
conversion. But I dunno if the required software/hardware exists. A Google
might help there.

--
*If you try to fail, and succeed, which have you done?

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

In message , "Dave Plowman (News)"
writes
In article ,
Graz wrote:
You might be able to do it properly via your PC.

I'd be interested to know what's involved.

A PC should have the processing power required to do a pukka standards
conversion. But I dunno if the required software/hardware exists. A Google
might help there.


Using a PC, "just for fun", I've successfully converted PAL TV DVD
recordings to NTSC, and vice versa. But of course, I wasn't starting
with raw video, which is what you would have when the source is a VCR.
With a DVD, you pick the files off the DVD, and transcode them. However,
with a cheap TV video card, you should be able to feed the VCR video
into a PC, and get it into a file format suitable for transcoding. After
that, instead of transferring to tape, burn the finished product to a
DVD (if this is an acceptable alternative).

[Just a note: I have a dirt-cheap Alba DVD player which, when playing an
'NTSC' DVD, the output composite video is switchable between original
video (with the NTSC 3.58MHz subcarrier) and the PAL 4.43MHz. With NTSC
output, the PAL TV set goes to B&W, and the subcarrier is very visible.
This 'feature' is useful for determining if a NTSC-PAL conversion has
actually worked. I'm not sure if the 'feature' works the other way
around. I must check some day.]

The success of my home-made transcodings can only be described as
'fair'. Occasionally, there is a certain amount of 'juddering' because
of the 50Hz-60Hz difference of field frequency. Also, there is a
possibility of the video and audio being a bit out-of-sync.
--
Ian

On 21 Dec 2008 17:48:43 GMT, Allodoxaphobia
put finger to keyboard and composed:

On Sun, 21 Dec 2008 15:38:38 GMT, Graz wrote:
On Sun, 21 Dec 2008 "Dave Plowman (News)" wrote:

Cludge? Is that a technical term? :-)

Yes. Spelled wrong. "Kludge", IIANM

It was originally spelt "kluge":
http://dictionary.reference.com/search?q=kluge

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Mon, 22 Dec 2008 11:13:24 +1100, Franc Zabkar
wrote:

On 21 Dec 2008 17:48:43 GMT, Allodoxaphobia
put finger to keyboard and composed:

On Sun, 21 Dec 2008 15:38:38 GMT, Graz wrote:
On Sun, 21 Dec 2008 "Dave Plowman (News)" wrote:

Cludge? Is that a technical term? :-)

Yes. Spelled wrong. "Kludge", IIANM

It was originally spelt "kluge":
http://dictionary.reference.com/search?q=kluge

Ah, as I thought - related to botch/bodge.

On Sun, 21 Dec 2008 19:58:41 +0000, Ian Jackson
wrote:

In message , "Dave Plowman (News)"
writes
In article ,
Graz wrote:
You might be able to do it properly via your PC.

I'd be interested to know what's involved.

A PC should have the processing power required to do a pukka standards
conversion. But I dunno if the required software/hardware exists. A Google
might help there.


Using a PC, "just for fun", I've successfully converted PAL TV DVD
recordings to NTSC, and vice versa. But of course, I wasn't starting
with raw video, which is what you would have when the source is a VCR.
With a DVD, you pick the files off the DVD, and transcode them. However,
with a cheap TV video card, you should be able to feed the VCR video
into a PC, and get it into a file format suitable for transcoding. After
that, instead of transferring to tape, burn the finished product to a
DVD (if this is an acceptable alternative).

[Just a note: I have a dirt-cheap Alba DVD player which, when playing an
'NTSC' DVD, the output composite video is switchable between original
video (with the NTSC 3.58MHz subcarrier) and the PAL 4.43MHz. With NTSC
output, the PAL TV set goes to B&W, and the subcarrier is very visible.
This 'feature' is useful for determining if a NTSC-PAL conversion has
actually worked. I'm not sure if the 'feature' works the other way
around. I must check some day.]

The success of my home-made transcodings can only be described as
'fair'. Occasionally, there is a certain amount of 'juddering' because
of the 50Hz-60Hz difference of field frequency. Also, there is a
possibility of the video and audio being a bit out-of-sync.

Incidentally, how common are multi-region DVD players in the USA?
Over here, it seems that many of the cheap brands are multi-region
while the known brands are Region 2 (Europe) only.

On Mon, 22 Dec 2008 05:40:37 GMT, (Graz) wrote:

On Sun, 21 Dec 2008 19:58:41 +0000, Ian Jackson
wrote:

In message , "Dave Plowman (News)"
writes
In article ,
Graz wrote:
You might be able to do it properly via your PC.

I'd be interested to know what's involved.

A PC should have the processing power required to do a pukka standards
conversion. But I dunno if the required software/hardware exists. A Google
might help there.


Using a PC, "just for fun", I've successfully converted PAL TV DVD
recordings to NTSC, and vice versa. But of course, I wasn't starting
with raw video, which is what you would have when the source is a VCR.
With a DVD, you pick the files off the DVD, and transcode them. However,
with a cheap TV video card, you should be able to feed the VCR video
into a PC, and get it into a file format suitable for transcoding. After
that, instead of transferring to tape, burn the finished product to a
DVD (if this is an acceptable alternative).

[Just a note: I have a dirt-cheap Alba DVD player which, when playing an
'NTSC' DVD, the output composite video is switchable between original
video (with the NTSC 3.58MHz subcarrier) and the PAL 4.43MHz. With NTSC
output, the PAL TV set goes to B&W, and the subcarrier is very visible.
This 'feature' is useful for determining if a NTSC-PAL conversion has
actually worked. I'm not sure if the 'feature' works the other way
around. I must check some day.]

The success of my home-made transcodings can only be described as
'fair'. Occasionally, there is a certain amount of 'juddering' because
of the 50Hz-60Hz difference of field frequency. Also, there is a
possibility of the video and audio being a bit out-of-sync.

Incidentally, how common are multi-region DVD players in the USA?
Over here, it seems that many of the cheap brands are multi-region
while the known brands are Region 2 (Europe) only.

If you want to do one tape I sugest to go to a store that does that
type of conversion.

In article ,
"John,A" wrote:
If you want to do one tape I sugest to go to a store that does that
type of conversion.

Could you easily find a store in the US that does NTSC to PAL conversion?
The other way round is more likely.

Same applies in the UK.

--
*Errors have been made. Others will be blamed.

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

In message , "Dave Plowman (News)"
writes
In article ,
"John,A" wrote:
If you want to do one tape I sugest to go to a store that does that
type of conversion.

Could you easily find a store in the US that does NTSC to PAL conversion?
The other way round is more likely.

Same applies in the UK.

I agree that, for just one tape, a 'store conversion' would save a lot
of messing about. I was more interested in trying to defeat the
idiosyncrasies of Nero (and other multimedia processing software) than
actually trying to do anything useful.

I'm no real expert. Ten years ago, I had a couple of tapes (of a wedding
in the USA) 'professionally' converted (in the UK) to PAL. I recall that
the results were not too impressive. [Soon afterwards, my old PAL-only
VCR packed up. The replacement could play NTSC tapes anyway, so the
conversion was a bit of a waste of money!] I think that my own
more-recent efforts on the PC were actually better.

I'm not sure how common 'store conversion' facilities are these days.
However, ten years ago, when I was interested, I think that most used to
offer conversions either way. I don't think that there should be any
difficulty in getting a PAL-to-NTSC conversion done in the UK.
--
Ian

In article ,
Ian Jackson wrote:
I'm no real expert. Ten years ago, I had a couple of tapes (of a wedding
in the USA) 'professionally' converted (in the UK) to PAL. I recall that
the results were not too impressive.

Likely done by pointing a camera at a monitor. Proper standards convertors
were/are extremely expensive. And only really to be found within broadcast
facilities. But then copying any VHS results in very noticeable
degradation - even without standards conversion.

--
*I'm out of my mind, but feel free to leave a message.

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

Dave Plowman (News) wrote:

Likely done by pointing a camera at a monitor. Proper standards convertors
were/are extremely expensive. And only really to be found within broadcast
facilities. But then copying any VHS results in very noticeable
degradation - even without standards conversion.

I had done that in the 1980's. By 1991, I had a panasonic converting VCR
that did digital conversions. That worked until about 3 years ago when it
had a mechanical fault, and the people that repaired it tore the ribbon cable
that controlled the converter. I still have it and was able to replace enough
wires in the cable to get to work as a VCR, but for now the converter is gone.

I've since replaced it with an Aiwa that does the same thing.

BTW, the OP's problem is with Nero, PAL DVD players have no trouble playing
NTSC DVD's on PAL TV sets. Some of them automaticly adjust, some have a
setup option.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

"Dave Plowman (News)" wrote:

In article ,
"John,A" wrote:
If you want to do one tape I sugest to go to a store that does that
type of conversion.

Could you easily find a store in the US that does NTSC to PAL conversion?
The other way round is more likely.


At one time I knew of three, but I moved from that small town. One
was a professional video duplication house that only worked with VHS &
U-matic, while the others converted almost anything from 8 mm film, to
foreign tape formats.

Some TV stations have the capability to import foreign tape formats
to NTSC time base corrected video and can record in NTSC VHS format, if
yo know someone in the video engineering department.


Same applies in the UK.

--
*Errors have been made. Others will be blamed.

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


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

In article ,
Michael A. Terrell wrote:

"Dave Plowman (News)" wrote:

In article ,
"John,A" wrote:
If you want to do one tape I sugest to go to a store that does that
type of conversion.

Could you easily find a store in the US that does NTSC to PAL
conversion? The other way round is more likely.


At one time I knew of three, but I moved from that small town. One
was a professional video duplication house that only worked with VHS &
U-matic, while the others converted almost anything from 8 mm film, to
foreign tape formats.

As I said earlier it depends on what quality you want the conversion done
to - a proper one cost a lot of money. But a camera on a monitor will do
the conversion - that's how early broadcast ones worked.

Some TV stations have the capability to import foreign tape formats
to NTSC time base corrected video and can record in NTSC VHS format, if
yo know someone in the video engineering department.

Indeed - my former employer had a full blown standards convertor which
cost 100s of thousands of pounds. How else did you get to watch
Benny Hill? ;-)


Same applies in the UK.

--
*Constipated People Don't Give A Crap*

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

In article ,
Geoffrey S. Mendelson wrote:
BTW, the OP's problem is with Nero, PAL DVD players have no trouble
playing NTSC DVD's on PAL TV sets. Some of them automaticly adjust, some
have a setup option.

Thing is it's a bit of a misnomer talking about PAL or NTSC DVDs - as they
aren't actually coded to either. It's just the line and frame rates that
differ - and of course there are different ones of those on both PAL and
NTSC, IIRC, in various countries. In other words the digits on the disc
aren't PAL or NTSC encoded. And if you're feeding them to the TV in
digital, RGB or components again it doesn't matter - only if composite or
RF does PAL or NTSC really come into the equation. So I suppose it's
really just convention that they are marked PAL or NTSC - to show the
countries they're for.

--
*To steal ideas from *one* person is plagiarism; from many, research*

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

Dave Plowman (News) wrote:
Thing is it's a bit of a misnomer talking about PAL or NTSC DVDs - as they
aren't actually coded to either. It's just the line and frame rates that
differ - and of course there are different ones of those on both PAL and
NTSC, IIRC, in various countries. In other words the digits on the disc
aren't PAL or NTSC encoded. And if you're feeding them to the TV in
digital, RGB or components again it doesn't matter - only if composite or
RF does PAL or NTSC really come into the equation. So I suppose it's
really just convention that they are marked PAL or NTSC - to show the
countries they're for.

Yes, and no. DVD's are component video not RGB and they can be in one of
3 frame rates. NTSC film (24/1001), PAL (25) and NTSC video (30/1001).

Even HTDV has different frame rates, PAL/SECAM zones use 25 fps, NTSC zones
use 30/1001. AFAIK, no TV sets actually play 24/1001 video.

The first DVD player I bought, circa 2000 had a choice between multisystem
and PAL TV sets as a setup option. So have all the successive ones, except
a Sansui bought around 2001, which had a multisystem/PAL switch on the back.

The Sansui one was also the only one that was zoned, at it could be converted
by entering PI at the right time on the remote. The instructions were on
a piece of paper included in the box by the importer.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

DVDs are component video not RGB and they can be in one of
3 frame rates. NTSC film (24/1001), PAL (25) and NTSC video (30/1001).

The first DVD player I bought, circa 2000 had a choice between multisystem
and PAL TV sets as a setup option. So have all the successive ones, except
a Sansui bought around 2001, which had a multisystem/PAL switch on the
back.

The Sansui one was also the only one that was zoned, at it could be
converted
by entering PI at the right time on the remote. The instructions were on
a piece of paper included in the box by the importer.

This raises a question that I've long wanted an answer to... If disks vary
according to frame rate -- how can there be a zone-free recording?

In article ,
Geoffrey S. Mendelson wrote:
Dave Plowman (News) wrote:
Thing is it's a bit of a misnomer talking about PAL or NTSC DVDs - as
they aren't actually coded to either. It's just the line and frame
rates that differ - and of course there are different ones of those on
both PAL and NTSC, IIRC, in various countries. In other words the
digits on the disc aren't PAL or NTSC encoded. And if you're feeding
them to the TV in digital, RGB or components again it doesn't matter -
only if composite or RF does PAL or NTSC really come into the
equation. So I suppose it's really just convention that they are
marked PAL or NTSC - to show the countries they're for.

Yes, and no. DVD's are component video not RGB and they can be in one of
3 frame rates. NTSC film (24/1001), PAL (25) and NTSC video (30/1001).

Indeed - but as I said not actually PAL. That refers to phased alternate
line. And designed to overcome problems with transmission that NTSC
suffers from.

--
*Nothing is foolproof to a sufficiently talented fool*

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

Indeed - but as I said not actually PAL. That refers to phased
alternate line. And designed to overcome problems with
transmission that NTSC suffers from.

While introducing problems of its own, such as severe desaturation under
conditions of excessive group-delay error.

In article ,
William Sommerwerck wrote:
Indeed - but as I said not actually PAL. That refers to phased
alternate line. And designed to overcome problems with
transmission that NTSC suffers from.

While introducing problems of its own, such as severe desaturation under
conditions of excessive group-delay error.

Wasn't being jingoistic, BTW. There is always a downside being first like
with NTSC. But I'm not sure what you mean by group delay?

IIRC was taught that NTSC gives the best off camera pictures, PAL for
processing and recorded to tape and SECAM for transmission?

--
*Why is it called tourist season if we can't shoot at them?

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

William Sommerwerck wrote:
This raises a question that I've long wanted an answer to... If disks vary
according to frame rate -- how can there be a zone-free recording?

Because all players play all three frame rate disks. Zones refer only
to encryption. If a disk is not encrypted, then it can be played on any
DVD player. Home DVDs are not encrypted, in fact, I have never seen
DVD encryption software for home users, but it may exist.

Commerical DVDs are encrypted if the producer wants to use it. There may
be a licensing fee for involved. All licensed players are required to
check the zone bits (1-8) before decrypting a DVD to make sure the
player's zone is allowed by they DVD.

If you wish to produce a zone-free recording, you can leave it unencrypted
or encrypt it with more than one zone allowed. Israel is in zone 2, I
usually see zone 1 or 2 only disks for sale here, occasionaly I see disks
for zone 2 and 4, 2 and 6, or 2, 4 and 6.

The following web page discusses the permitted resolutions and frame rates
allowed by DVDs:

http://www.mplayerhq.hu/DOCS/HTML/en...t-vcd-dvd.html

Note that I have found you can mix some of the video and audio encoding
options in ways that are not permitted and they still work. Surprisingly
doing so produced a DVD that could be played on everything I tried including
several hard and soft players EXCEPT Windows Media Player.

Geoff.



--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Indeed - but as I said not actually PAL. That refers to phased
alternate line. And designed to overcome problems with
transmission that NTSC suffers from.

While introducing problems of its own, such as severe desaturation under
conditions of excessive group-delay error.

Wasn't being jingoistic, BTW. There is always a downside being first like
with NTSC. But I'm not sure what you mean by group delay?

IIRC was taught that NTSC gives the best off camera pictures, PAL for
processing and recorded to tape and SECAM for transmission?

NTSC and PAL are pretty much Tweedle-Dum and Tweedle-Dee. There's no
significant difference between them. PAL is essentially NTSC with phase
alternation. (Which was supposed to be part of NTSC, but the designers
couldn't see any way to build an inexpensivd TV receiver to take full
advantage of it, so it was dropped.)

At the time Europe adopted PAL, the transmission systems had a lot of
non-linear group delay (the US systems didn't), which alters the hue. The
phase alternation causes the hue shifts to be "opposite" (complementary) on
alternate lines, so there is a visual averaging of the hue. This is good, up
to a point, but as the averaging pushes the color towards white, the effect
is visible desaturation.

In article ,
William Sommerwerck wrote:
At the time Europe adopted PAL, the transmission systems had a lot of
non-linear group delay (the US systems didn't), which alters the hue.
The phase alternation causes the hue shifts to be "opposite"
(complementary) on alternate lines, so there is a visual averaging of
the hue. This is good, up to a point, but as the averaging pushes the
color towards white, the effect is visible desaturation.

Never seen this - despite having had colour TV since it started in the UK.

But I'm still not sure what you mean by 'non linear group delay'.

--
*Virtual reality is its own reward *

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

But I'm still not sure what you mean by 'non linear group delay'.

Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.

"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:

"Dave Plowman (News)" wrote:

In article ,
"John,A" wrote:
If you want to do one tape I sugest to go to a store that does that
type of conversion.

Could you easily find a store in the US that does NTSC to PAL
conversion? The other way round is more likely.

At one time I knew of three, but I moved from that small town. One
was a professional video duplication house that only worked with VHS &
U-matic, while the others converted almost anything from 8 mm film, to
foreign tape formats.

As I said earlier it depends on what quality you want the conversion done
to - a proper one cost a lot of money. But a camera on a monitor will do
the conversion - that's how early broadcast ones worked.

Some TV stations have the capability to import foreign tape formats
to NTSC time base corrected video and can record in NTSC VHS format, if
yo know someone in the video engineering department.

Indeed - my former employer had a full blown standards convertor which
cost 100s of thousands of pounds. How else did you get to watch
Benny Hill? ;-)


On BBC America.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

In article ,
William Sommerwerck wrote:
But I'm still not sure what you mean by 'non linear group delay'.

Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.

Right. And just where would you get this?

--
*If one synchronized swimmer drowns, do the rest have to drown too?

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

"Dave Plowman (News)" wrote in message
...
In article ,
William Sommerwerck wrote:

But I'm still not sure what you mean by 'non linear group delay'.

Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.

Right. And just where would you get this?

From less-than-well-designed transmission systems.

The US had microwave systems which generally had low group-delay errors. In
the late '50s, Europe had coax systems which generally did not. Which was
one of the reasons PAL was selected. According to the books, anyhow.

William Sommerwerck wrote:

"Dave Plowman (News)" wrote in message
...
In article ,
William Sommerwerck wrote:

But I'm still not sure what you mean by 'non linear group delay'.

Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.

Right. And just where would you get this?

From less-than-well-designed transmission systems.

The US had microwave systems which generally had low group-delay errors. In
the late '50s, Europe had coax systems which generally did not. Which was
one of the reasons PAL was selected. According to the books, anyhow.


I knew an old ATT guy who worked in both cross country coaxial &
microwave video feeds. He told me how much of a pain it was to equalize
a section of cross county coax used for network TV feeds, and keep it
that way as the temperature changed.

The emergency lashup to cover the JFK assignation was via coax that
wasn't properly equalized, and you could tell from the muddy video.
There was barely enough extra capacity to do it without notice, but all
of the three networks were able to get the live feed at all of their
stations. Some sections of failing coax had to be used, since it was all
that was available without dumping other customers.

That was at a time they were working to eliminate the last of the
cross country coaxial trunklines. They still used coaxial feeds from
the nearest microwave tower to the TV station. Now most of the
microwave sites are gone, having been replaced with fiber optic cable.


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The first sign of insanity is denying that you're crazy.

In article ,
William Sommerwerck wrote:
"Dave Plowman (News)" wrote in message
...
In article ,
William Sommerwerck wrote:

But I'm still not sure what you mean by 'non linear group delay'.

Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.

Right. And just where would you get this?

From less-than-well-designed transmission systems.

The US had microwave systems which generally had low group-delay errors.
In the late '50s, Europe had coax systems which generally did not. Which
was one of the reasons PAL was selected. According to the books, anyhow.

Thanks for the explanation. Could explain why I've not heard of it. In the
UK microwave links tended only to be used for linking say an outside
broadcast back to a receiving area. To transmitters is generally cable -
although one channel does use satellite. And of course satellite is
getting more common for the former task.

--
*When it rains, why don't sheep shrink? *

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

I knew an old ATT guy who worked in both cross country coaxial
& microwave video feeds. He told me how much of a pain it was to
equalize a section of cross county coax used for network TV feeds,
and keep it that way as the temperature changed.

Thanks for the confirmation. I didn't realize coax was so
temperature-sensitive.

In message , William Sommerwerck
writes
I knew an old ATT guy who worked in both cross country coaxial
& microwave video feeds. He told me how much of a pain it was to
equalize a section of cross county coax used for network TV feeds,
and keep it that way as the temperature changed.

Thanks for the confirmation. I didn't realize coax was so
temperature-sensitive.

Its attenuation changes by appx .02dB per dB per degree C.
--
Ian

In article ,
Ian Jackson wrote:
In message , William Sommerwerck
writes
I knew an old ATT guy who worked in both cross country coaxial
& microwave video feeds. He told me how much of a pain it was to
equalize a section of cross county coax used for network TV feeds,
and keep it that way as the temperature changed.

Thanks for the confirmation. I didn't realize coax was so
temperature-sensitive.

Its attenuation changes by appx .02dB per dB per degree C.

In the UK it would normally be buried underground - so kept at a fairly
constant temperature. But just shows the difference between a small
country like the UK and somewhere so vast as the US. Or perhaps that the
co-ax was installed by a state owned company with a monopoly so costs
perhaps weren't the main priority.

--
*Don't worry; it only seems kinky the first time.*

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

William Sommerwerck wrote:

I knew an old ATT guy who worked in both cross country coaxial
& microwave video feeds. He told me how much of a pain it was to
equalize a section of cross county coax used for network TV feeds,
and keep it that way as the temperature changed.

Thanks for the confirmation. I didn't realize coax was so
temperature-sensitive.


You should see what it does to solid aluminum jacketed coax during a
sudden temperature drop. The shield can shrink three inches in a 500
foot run, and either pull the jacket out of the connector, or rip the
aluminum. It is called a suckout in CATV slang.

CATV mostly solved the problems by using the video carrier of two
channels to calculate the tilt, and compensate at each amplifier. The
systems I worked on used Ch. 2 & Ch. 12. That meant that any headend
needed a minimum of those two channels to work. A replacement signal at
the same level had to be provided at the head end if those were off the
air channels. We used locally generated video for both channels.

The ATT coax was miles long segments with tube amplifiers & equalizers
at fixed distances. Without careful setup of a hundred or more of those
terminals, the equalization destroyed the signal.


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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

Ian Jackson wrote:

In message , William Sommerwerck
writes
I knew an old ATT guy who worked in both cross country coaxial
& microwave video feeds. He told me how much of a pain it was to
equalize a section of cross county coax used for network TV feeds,
and keep it that way as the temperature changed.

Thanks for the confirmation. I didn't realize coax was so
temperature-sensitive.

Its attenuation changes by appx .02dB per dB per degree C.


At what distance? At what frequency?


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There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

In message , Michael A.
Terrell writes

Ian Jackson wrote:

In message , William Sommerwerck
writes
I knew an old ATT guy who worked in both cross country coaxial
& microwave video feeds. He told me how much of a pain it was to
equalize a section of cross county coax used for network TV feeds,
and keep it that way as the temperature changed.

Thanks for the confirmation. I didn't realize coax was so
temperature-sensitive.

Its attenuation changes by appx .02dB per dB per degree C.


At what distance? At what frequency?

Any and any.
Think about it.
--
Ian