Is NTSC analogue or digital?

ckrys1

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#1
I occasionally watch feeds from 43W and 45W which, despite a good signal on the signal bar, produce a jumpy, coming and going picture, and am told that this is because the transmission is in NTSC, and my box(Humax 5300), can`t deal with this properly. An NTSC-PAL converter(analogue) simply made the picture worse.
I`m confused because I thought all digital signals (in Europe anyway) were MPEG2, and my receiver would convert them to PAL, so that I can watch them on a PAL TV. So how can a digital signal be NTSC, which I thought was an analogue format used (mainly) in the USA? And more importantly, does anyone know how I can resolve the problem?.
Humax tell me there is software to make my box NTSC compatible, but this may upset the PAL output. I wonder if I bought a cheap receiver from USA, to use only for those feeds, would that work?
Thanks in advance

Ckrys1
 

rolfw

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#2
I must confess Ckrys1, that I don't know too much about this, but like you thought that MPEG2 was a universal video compression standard and so would work on any receiver capable of decompressing that standard. Therefor it should be irrelevent whether the final output is NTSC, Secam or PAL.

There could of course be other reasons why you are having problems with the video, could be the Symbol rate, viterbi rate or insufficient signal quality.

Rolf
 

ckrys1

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#3
Makes me feel better that you`re confused too!
Symbol rate is fairly standard, I think 5632, and signal quality is 70-80%. Have asked a few friends with receivers other than Humax, and they have the same problem. Anyone else cast any light?

Ckrys1
 

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#4
The other thing I would add is that when I used to use old NTSC Video Discs for Karaoke they were always in NTSC and showed in monochrome, but the picture as far as I can remember was stable.

Rolf
 

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#5
Could be a number of problems, as you say the compatibility of the receiver would be the first to check by substitution

The feeds from the States could be converted from NTSC to PAL before they are uplinked, the conversion may be done to the video signal before change to digital, or they could be on their second hop (possibly a relay feed) and are being converted to suit the tranfer equipment.

The conversion could be to the colour, the vertical height, the screen format, the frame rate (50 to 60 Hz or vice versa) or a combination of all.

If you find the signal strength changes and the picture drops out, first try conecting the receiver to the TV via a SCART using RGB signals, then alter the receiver TV output to either NTSC or AUTO if there is one.

If the picture fall over or stops every one and a half seconds then you have a PAL set of chips in the receiver which cannot cope with converting the signal to the right output for viewing.
 

ckrys1

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#6
Thanks CH.
Tried the scart with RGB output - no differnce.
Unfortunately, no NTSC or AUTO output on receiver.
So looks like I`m stuck, unless funds can accumulate to buy an American receiver. If I did this, do you know if it would show the Powervu channels on 45W (ESPN amongst others) or is that too much to hope for?
In case you`re wondering why I want the feeds from 43W, they show Brazilian league football live on Sunday nights.

Ckrys1
 

rolfw

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#7
Just as a matter of interest, does your receiver handle Single Channel per Carrier, if not that may be part of your problem, as most of the feeds are exactly that. It also may be that with regard to the RGB output, if your TV does not handle RGB signals merely switching to RGB on the sat receiver will not be enough.

The Powervu I believe is not merely a different encryption but also a different compression method, so you may have problems.

rolf
 

ckrys1

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Yes - the Humax handles SCPC ok.
Take the point about RGB, although I think my TV is ok with that, on the basis that a friend with the same receiver but older tv has to have receiver output set to something called CVBS (whatever that is!) to get a picture, while I can set to CVBS or RGB.
With regard to powervu, I think 2old4thishas previously posted that it is not an encryption, but a compression standard akin to, but different from,
MPEG2. In which case, somebody somewhere must have receivers to handle this, otherwise why transmit? And it`s not feeds I`m thinking of, but ordinary channels particularly ESPN on 45W. With the Humax I get perfect audio, but a blank screen. A search on the web for an American sat receiver for powervu and NTSC compatibility has so far led to nothing at all, but I`ll keep searching.
Always think there must be an answer somewhere!!

Ckrys1
 

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#9
CBVS - Composite Baseband Video source (or supply)

A single output (usually from a phono plug on the receiver), or pin 19 of the SCART socket on the TV output

This signal is the standard way of all receivers delivering video down one cable, RGB as an alternative requires at least five wires (three for the colours, one for sync and a common ground.

Most modern TVs would have the option of setting up either (though there has been some discussion about Philips and non compatibilty with switching from normal to widescreen), using most types of receiver on the market.

The way of determining what part of the signal prevents the viewing of these signals on 43W would be to look at a true NTSC signal on an MCPC, some of these are sometimes found on 21 West, though a quicker solution would be to look at 43 W with another receiver.

By the way the Techsan 4000 CI unit I use here has selections within the TV set up menu for NTSC and PAL, RGB and CBVS, and the transmissions come through clearly on the NTSC, though I need to set up the multi system TV to NTSC then to view them. I do not htink most TVs have an independent path for non European derived signals so the picture will either roll, or be of the wrong height.
 

w hole

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#10
[updated:LAST EDITED ON 06-Dec-01 AT 07:17 PM (GMT)]Hello All

I use a Humax F1-CI which does give me a decent picture on these transmissions, but as you say they are not of the correct height, it displays a black band at the bottom.

I rememeber a recent discussion on this topic somewhere recently and it seems that some Humax Models will resolve these signals and some won't.

I would have thought that it would be worth trying the updated software for you STB, but only if you can be sure to restore the original if it doesn't work.

Hope the Moderator won't mind me telling you about another group:

http://groups.yahoo.com/group/humax-users

which is very active, and may be worth posting to.

Good luck

W Hole


PS. Chrys - For some reason my Humax-users mailings have not been comming through since 01DEC - I have just checked the backlog, and can see that you have already been there - Oohps...

But there was some detailed discussion apart from this thread or the current Humax-users one somewhere recently, but I can't rememebr where it was now...I think it even contained a list of all the receivers and their compatability or otherwise with these NTSCT feeds.
 
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#11
could it be that your receiver is trying to display ATSC (the american standard for digital TV) as a DVB transmission?

i aint too good on this but this might be thae cause. if you check on www.lyngsat.com you can look up your satellites and see if they are using the DVB standard.

Scabby
 
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#12
If your TV handles NTSC through the SCART (not R.F) and the receiver handles NTSC there should be no problem.
I have an Echostar AD3000 and Toshiba 36" TV and am able to watch, in colour and at the right size, the MSNBC transmissions on Telstar12 which are in true NTSC
 
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#13
Hello ckrys1.
What was the frequency you tried to receive ?
Did you get good audio ?
Are you sure the feed wasn't in 4.2.2 ?
Have you tried NTSC on other satellites ?
Regards.
amdaley28 :)
 
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