OT Trying to copy a VHS tape in NTSC format (UK)
Graz
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?
William Sommerwerck
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.
Dave Plowman (News)
Graz <gr...@gmail.com> 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 da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Graz
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.
Graz
<da...@davenoise.co.uk> wrote:
>In article <494e1e13....@news.motzarella.org>,
> Graz <gr...@gmail.com> 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.
b
> On Sun, 21 Dec 2008 12:53:56 +0000 (GMT), "Dave Plowman (News)"
>
> >In article <494e1e13.267499...@news.motzarella.org>,
> > Graz <g...@gmail.com> 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
Allodoxaphobia
> On Sun, 21 Dec 2008 "Dave Plowman (News)" wrote:
>
> Cludge? Is that a technical term? :-)
Yes. Spelled wrong. "Kludge", IIANM
Dave Plowman (News)
> 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?
Ian Jackson
<da...@davenoise.co.uk> writes
>In article <494e62d0....@news.motzarella.org>,
> Graz <gr...@gmail.com> 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
Franc Zabkar
put finger to keyboard and composed:
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.
Graz
<fza...@iinternode.on.net> wrote:
>On 21 Dec 2008 17:48:43 GMT, Allodoxaphobia <bit-b...@config.com>
>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.
Graz
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.
Unknown
If you want to do one tape I sugest to go to a store that does that
type of conversion.
Dave Plowman (News)
"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.
Ian Jackson
<da...@davenoise.co.uk> writes
>In article <nri0l4lqc0cjgj5cs...@4ax.com>,
> "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.
>
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
Dave Plowman (News)
Ian Jackson <ianREMOVET...@g3ohx.demon.co.uk> 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.
Geoffrey S. Mendelson
> 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 g...@mendelson.com N3OWJ/4X1GM
Michael A. Terrell
"Dave Plowman (News)" wrote:
>
> In article <nri0l4lqc0cjgj5cs...@4ax.com>,
> "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 da...@davenoise.co.uk 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.
Dave Plowman (News)
Michael A. Terrell <mike.t...@earthlink.net> wrote:
> "Dave Plowman (News)" wrote:
> >
> > In article <nri0l4lqc0cjgj5cs...@4ax.com>,
> > "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 (News)
Geoffrey S. Mendelson <g...@mendelson.com> 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*
Geoffrey S. Mendelson
> 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.
William Sommerwerck
> 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?
Dave Plowman (News)
> > 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*
William Sommerwerck
> 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.
Dave Plowman (News)
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?
Geoffrey S. Mendelson
> 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/menc-feat-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.
William Sommerwerck
> > > 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.
Dave Plowman (News)
William Sommerwerck <grizzle...@comcast.net> 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 *
William Sommerwerck
Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.
Michael A. Terrell
"Dave Plowman (News)" wrote:
>
> In article <rpadnfZ38aRrVc3U...@earthlink.com>,
> Michael A. Terrell <mike.t...@earthlink.net> wrote:
>
> > "Dave Plowman (News)" wrote:
> > >
> > > In article <nri0l4lqc0cjgj5cs...@4ax.com>,
> > > "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.
Dave Plowman (News)
Right. And just where would you get this?
--
*If one synchronized swimmer drowns, do the rest have to drown too?
William Sommerwerck
news:50126f1...@davenoise.co.uk...
> In article <girdk3$ht7$1...@news.motzarella.org>,
> William Sommerwerck <grizzle...@comcast.net> wrote:
>>> But I'm still not sure what you mean by 'non linear group delay'.
>> Phase shift in which the shift is not linearly proportional to the
>> frequency, along a straight line that passes through the origin.
> Right. And just where would you get this?
From less-than-well-designed transmission systems.
The US had microwave systems which generally had low group-delay errors. In
the late '50s, Europe had coax systems which generally did not. Which was
one of the reasons PAL was selected. According to the books, anyhow.
Michael A. Terrell
I knew an old ATT guy who worked in both cross country coaxial &
microwave video feeds. He told me how much of a pain it was to equalize
a section of cross county coax used for network TV feeds, and keep it
that way as the temperature changed.
The emergency lashup to cover the JFK assignation was via coax that
wasn't properly equalized, and you could tell from the muddy video.
There was barely enough extra capacity to do it without notice, but all
of the three networks were able to get the live feed at all of their
stations. Some sections of failing coax had to be used, since it was all
that was available without dumping other customers.
That was at a time they were working to eliminate the last of the
cross country coaxial trunklines. They still used coaxial feeds from
the nearest microwave tower to the TV station. Now most of the
microwave sites are gone, having been replaced with fiber optic cable.
Dave Plowman (News)
William Sommerwerck <grizzle...@comcast.net> wrote:
> "Dave Plowman (News)" <da...@davenoise.co.uk> wrote in message
> news:50126f1...@davenoise.co.uk...
> > In article <girdk3$ht7$1...@news.motzarella.org>,
> > William Sommerwerck <grizzle...@comcast.net> 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? *
William Sommerwerck
> & 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.
Ian Jackson
<grizzle...@comcast.net> writes
--
Ian
Dave Plowman (News)
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.*
Michael A. Terrell
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.
Michael A. Terrell
At what distance? At what frequency?
Ian Jackson
Terrell <mike.t...@earthlink.net> writes
>
>Ian Jackson wrote:
>>
>> In message <git910$7df$1...@news.motzarella.org>, William Sommerwerck
>> <grizzle...@comcast.net> 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?
>
Think about it.
--
Ian
Ian Jackson
Terrell <mike.t...@earthlink.net> writes
>
>
> 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.
>
messenger wire stretched between the utility poles, the coax can indeed
undergo horrendous changes of temperature (both on a daily and a
seasonal basis). To allow for the physical expansion and contraction
which occurs, it is pretty well mandatory to have an expansion loop near
each pole. This prevents the cable being wrenched out of the connectors
at low temperatures. While the line guys may call this a 'suckout', a
suckout normally refers to an unexpected notch in the frequency
spectrum. Of course, this might be a direct result of the jacket having
been partially or completely pulled out, leaving the inner as the only
connection.
--
Ian
Michael A. Terrell
Ian Jackson wrote:
>
> In message <JvydnUs4ceBJ28_U...@earthlink.com>, Michael A.
> Terrell <mike.t...@earthlink.net> writes
> >
> >Ian Jackson wrote:
> >>
> >> In message <git910$7df$1...@news.motzarella.org>, William Sommerwerck
> >> <grizzle...@comcast.net> 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.
I have. Let's say I have a 5000 foot piece of coax and a 5 foot
piece. One is used to 450 MHZ, and the other at 11 GHz. The change is
not the same.
You need a change per distance, and frequency, because each type of
cable has different loss characteristics.
Michael A. Terrell
It happens to buried cable, as well. I've had crews out on Christmas
day, after a 70 degree drop in under 12 hours. My workers had to use
propane torches to thaw their hands while digging through frozen dirt &
rock to make repairs.
Ian Jackson
>
>Ian Jackson wrote:
>>
>> In message <JvydnUs4ceBJ28_U...@earthlink.com>, Michael A.
>> Terrell <mike.t...@earthlink.net> writes
>> >
>> >Ian Jackson wrote:
>> >>
>> >> In message <git910$7df$1...@news.motzarella.org>, William Sommerwerck
>> >> <grizzle...@comcast.net> 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.
>
>
> I have. Let's say I have a 5000 foot piece of coax and a 5 foot
>piece. One is used to 450 MHZ, and the other at 11 GHz. The change is
>not the same.
>
> You need a change per distance, and frequency, because each type of
>cable has different loss characteristics.
>
>
At 450MHz and temperature T1 centigrade, your 5000 foot of coax will
have an attenuation of A1 dB.
[The value of A1 obviously depends on the characteristics of that
particular type of coax, and on its length. For a different frequency /
temperature / length / type of coax, the value of A1 will be different.]
At temperature T2, the change of attenuation will be approximately
(T2-T1) x 0.02 x A1 dB.
At 11GHz and temperature T1, your 5 foot of coax will have an
attenuation of A2 dB.
[Again, for a different frequency / temperature / length / type of coax,
different value of A1.]
At temperature T2, the change of attenuation will be approximately
(T2-T1) x 0.02 x A2 dB.
Essentially, you don't have to know anything about the frequency /
length / type of coax. Although these do determine the amount of initial
attenuation, all you need to know is the actual value of the initial
attenuation, and the change of temperature. The higher the initial
attenuation (for whatever reason), the greater will be the change of
attenuation.
--
Ian
Leo Tick
> 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?
>
this can be done fairly easily but one need a tv card in a PC like
Hauppague. The card and software will produce an AVI file and you can go
from there to a dvd or vcd is quite easy
Michael A. Terrell
Ian Jackson wrote:
>
> OK.
>
> At 450MHz and temperature T1 centigrade, your 5000 foot of coax will
> have an attenuation of A1 dB.
>
> [The value of A1 obviously depends on the characteristics of that
> particular type of coax, and on its length. For a different frequency /
> temperature / length / type of coax, the value of A1 will be different.]
>
> At temperature T2, the change of attenuation will be approximately
> (T2-T1) x 0.02 x A1 dB.
>
> At 11GHz and temperature T1, your 5 foot of coax will have an
> attenuation of A2 dB.
>
> [Again, for a different frequency / temperature / length / type of coax,
> different value of A1.]
>
> At temperature T2, the change of attenuation will be approximately
> (T2-T1) x 0.02 x A2 dB.
>
> Essentially, you don't have to know anything about the frequency /
> length / type of coax. Although these do determine the amount of initial
> attenuation, all you need to know is the actual value of the initial
> attenuation, and the change of temperature. The higher the initial
> attenuation (for whatever reason), the greater will be the change of
> attenuation.
You still need to know the length. I used to have to do the
calculations for CATV system design on a four banger calculator, before
PCs were common. Levels at the highest & lowest temperature was one
limiting factor of the amplifier spacings. Some cables that were almost
identical at first glance in the catalogs could be 100 feet difference
in maximum length. At that time, pressurized, fused disk was the best
.750 cable available, but it was so fragile we wouldn't use it. Then you
had to wade through all the various foam types, the DC resistance per
100 feet, maximum certified frequency and a dozen other numbers.
A 5000 foot cable will have twice the change of a 2500 foot cable
forthe same temperature change. You still haven't stated if your .02 dB
change/degree is per fook, per 100 feet, or per mile.
Jeroni Paul
> 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?
I've done that with a PC (you don't need latest technology, a PC from
2000 onwards may do). You need a TV capture card compatible with the
standard you have in your VHS tape. I have an Easy TV that can capture
both PAL and NTSC color video. Then a video card with TV output that
can output the standard you want to record. I have an ATI Radeon card
that can output both PAL and NTSC.
Plug the video to the capture card composite video input and view the
signal full screen. Then on the TV card video output you have the
signal converted Of course you need a VCR capable to record NTSC in
colour (which may be the hard part to get). It may be easier to
capture the video in an AVI file and burn it in a DVD.
bz
dnf1Hb6v9fs_Un...@earthlink.com:
Look at the examples he worked for you.
Those units are especially convenient because you do NOT need to go through
complex calculations.
The complex calculations have already been done and you are given the final
results. All you need to know is the starting temp, the final temp and the
loss at the starting temperature. Everything else has already been taken
into account.
The 5000 foot cable will start with twice the number of dB loss as the 2500
foot cable.
Therefore the change per degree will be twice as much, automatically.
As he said, you do NOT need to know the length or the frequency, all you
need to know is the dB loss and the temperature change.
The units are (dB change in loss per degree change in temperature) / (dB
loss at T1)
So, if you are given the current dB loss at T1 and multiply that by
(dB change per degree change in temperature) / (dB loss at T1)
You get dB change per degree change in temperature. You then multiply that
by degrees change and get dB change.
--
bz 73 de N5BZ k
please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.
bz+...@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
Geoffrey S. Mendelson
> The 5000 foot cable will start with twice the number of dB loss as the 2500
> foot cable.
> Therefore the change per degree will be twice as much, automatically.
One would hope, but it is not true. Everyone so far has assumed that
coax is a pipe with smooth sides. Put something in and it slows down
because it rubs against the sides, but it comes out basicly unchanged
with a linear degradation.
The problem is that coax is more like a set of one wavelength pipes with
an incomplete one at the end. How this effects the signal is dependent
upon the frequency.
If the coax is used for close to one frequency, such as a single channel
carrier, the effect will be the same. As the length approaches 1/2 wavelength
there will be more antenuation, but since it effects the single carrier
nearly the same amount, there will be minmal phase and linerarity distortion.
If the signal were on the other hand a baseband video signal, or a group
of channels such as an analog cable tv system with 200 channels ranging
from low band VHF to high band UHF and anywhere in between, it becomes
more complex.
These days, it's not as much of a problem as digital video is carried over
a few analog channels, and they are close in frequency.
It was also far more critical in the early days of color TV since there
were no such things as phase locked loops and other methods of decoding
a phase modulated signal without compensating for distortion.
Ian Jackson
Terrell <mike.t...@earthlink.net> writes
>
I have! It's 'per dB'.
I'm sure you must have used a similar rule-of-thumb formula yourself
(but maybe in Fahrenheit). Maybe you use one which requires you to know
the length and attenuation per unit length (which will give you the
actual attenuation). It all amounts to the same thing in the end.
Somewhere, you need to input numbers for (or which give you) the cable
attenuation.
Please read carefully:
The formula states that the cable attenuation changes by appx .02dB per
dB per degree C. Note the 'PER dB'. That 'dB' the actual cable
attenuation. A 5000 foot cable will have twice the attenuation of a 2500
foot cable so, as you rightly say, a 5000 foot cable will have twice the
change of a 2500 foot cable for the same temperature change.
To use that formula, the important thing is to know the ATTENUATION of
the cable. If you don't know this, you have to find out. You may know
this from actual measurement, or by calculation from the spec figures
for the loss per unit length at the frequency of interest, and the
actual length.
All I can say is "Thank heavens for optical fibre!"
--
Ian
Michael A. Terrell
You did pages of calculations to verify the data, because the
construction costs were over $18,000 US per mile. You also had to be
careful that an amp didn't get placed too close to an intersection, as
well as minimize the number of power supplies. The power company assumed
that they were all loaded at 95%, and didn't meter them. A rule of thumb
design would have to be cleaned up & modified to almost work, where a
properly designed coaxial plant simply worked the first time. Finally,
I bought a Commodore 64 and wrote my own software that not only did the
standard calculations, it did backfeeds. That is, lines run backwards
from a bridging amp or line extender's normal physical layout. We were
providing +10 dB on every channel to over 10,000 active ports. A well
designed system needed little maintenance. A poorly designed system
needed five to ten times the crew. Considering the then target lifetime
was a 20 year life, most systems weren't paid of for over ten years. If
it took much longer, you may never make a profit.
> Please read carefully:
> The formula states that the cable attenuation changes by appx .02dB per
> dB per degree C. Note the 'PER dB'. That 'dB' the actual cable
> attenuation. A 5000 foot cable will have twice the attenuation of a 2500
> foot cable so, as you rightly say, a 5000 foot cable will have twice the
> change of a 2500 foot cable for the same temperature change.
>
> To use that formula, the important thing is to know the ATTENUATION of
> the cable. If you don't know this, you have to find out. You may know
> this from actual measurement, or by calculation from the spec figures
> for the loss per unit length at the frequency of interest, and the
> actual length.
>
> All I can say is "Thank heavens for optical fibre!"
Until some idiot tries to steal copper wire and cuts thousands of
fibers, looking for drug or beer money.
BTW, Cable TV around here is 'Fiber Enhanced' which means that the
regular services are still on coax, and the internet, telephone and
other services are on fiber. Unless you have FIOS, it is still a piece
of coax between the CATV plant and your house, apartment, or
refrigerator box.
William Sommerwerck
> That "dB" the actual cable attenuation.
I did read that carefully, and wondered. It looked like a typo, as if you'd
accidentally added "per degree".
I've never seen this before, and I suspect most other readers didn't.
Geoffrey S. Mendelson
> Until some idiot tries to steal copper wire and cuts thousands of
> fibers, looking for drug or beer money.
Or even worse, cuts the fiber cables under the sea because they happen
to drop anchor in a forbidden zone. It has happened twice in 2008 to
an Arab owned consortium with cables to Egypt from Europe.
Since here in Israel we are not welcomed by the consortium, we had our own
cables routed elsewhere. :-)
bz
news:givqvq$3n1$1...@news.motzarella.org:
Actually, for things like temperature coefficient of resistivity(TCR),
such things as 'ohms per ohm per degree' are pretty common.
To be completely clear, TCR should be stated explicitly in units like.
ohms of change in value per ohm of initial resistance at T1 per degree
change.
When I used to design and build resistors and capacitors for Sprague in
the late 60's and early 70's, the components had spec'd TCR and TCC in
such terms.
Dave Garland
> Could you easily find a store in the US that does NTSC to PAL conversion?
I think so. If you are in a metro area with a lot of immigrants.
Out in the boondocks, no.
Dave
Peter Hucker
> On 21 dic, 16:38, g...@gmail.com (Graz) wrote:
>> On Sun, 21 Dec 2008 12:53:56 +0000 (GMT), "Dave Plowman (News)"
>>
>> <d...@davenoise.co.uk> wrote:
>> >In article <494e1e13.267499...@news.motzarella.org>,
>> > Graz <g...@gmail.com> 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!)
http://www.brainsystems.com/capsunlock/
--
http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com
While taxiing at London's Gatwick Airport, the crew of a U.S. Air flight departing for Ft. Lauderdale made a wrong turn and came nose to nose with a United 727.
An irate female ground controller lashed out at the U.S. Air crew, screaming:
"U.S. Air 2771, where the hell are you going? I told you to turn right onto Charlie taxiway! You turned right on Delta!
Stop right there. I know it's difficult for you to tell the difference between C and D, but get it right!"
Continuing her rage to the embarrassed crew, she was now shouting hysterically:
"god! Now you've screwed everything up! It'll take forever to sort this out! You stay right there and don't move till I tell you to!
You can expect progressive taxi instructions in about half an hour and I want you to go exactly where I tell you, when I tell you, and how I tell you! You got that, U.S. Air 2771?"
"Yes, ma'am," the humbled crew responded.
Naturally, the ground control communications frequency fell terribly silent after the verbal bashing of U.S. Air 2771.
Nobody wanted to chance engaging the irate ground controller in her current state of mind. Tension in every cockpit around Gatwick was definitely running high.
Just then an unknown pilot broke the silence and keyed his microphone, asking: "Wasn't I married to you once?"
Peter Hucker
> On 21 Dec 2008 17:48:43 GMT, Allodoxaphobia <bit-b...@config.com>
> 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
That looks more like the pronounciation of the big slidy downhill ice track.
You know you're a redneck when......
1. You take your dog for a walk and you both use the same tree.
2. You can entertain yourself for more than 15 minutes with a fly swatter.
3. Your boat has not left the driveway in 15 years.
4. You burn your yard rather than mow it.
5. You think "The Nutcracker" is something you do off the high dive.
6. The Salvation Army declines your furniture.
7.You offer to give someon! e the shirt off your back and they don't want it
8. You have the local taxidermist on speed dial.
9. You come back from the dump with more than you took.
10. You keep a can of Raid on the kitchen table.
11. Your wife can climb a tree faster than your cat.
12. Your grandmother has "ammo" on her Christmas list.
13. You keep flea and tick soap in the shower.
14. You've been involved in a custody fight over a hunting dog.
15. You go to the stock car races and don't need a program.
16. You know how many bales of hay your car will hold.
17. You have a rag for a gas cap.
18. Your house doesn't have curtains, but your truck does.
19. You wonder how service stations keep their rest-room's so clean.
20. You can spit without opening your mouth.
21. You consider your license plate personalized because your father made it.
22. Your lifetime goal is to own a fireworks stand.
23. You have a complete set of salad bowls and they all say "Cool Whip" on the side.
24. The biggest city you've ever been to is Wal-Mart.
25. Your working TV sits on top of your non-working TV.
26. You've used your ironing board as a buffet table.
27. A tornado hits your neighborhood and does $100,000 worth of improvements.
28. You've used a toilet brush to scratch your back.
29. You missed your 5th grade graduation because you were on jury duty.
30. You think fast food is hitting a deer at 65.