So what's the truth about lead-free solder ?

MORE reliable? Please elaborate.

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Reply to
clifto
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artefacts,

You would perhaps (or not) be amazed how much critical stuff like editing (for feature films even- and I mean some really serious ones) is - or certinly was - done from rushes that arrive on Beta SP tapes.

Given the huge investment in such kit I'd not be surprised if it's still quite common.

Graham

Reply to
Eeyore

Actually I think you may be speaking some truth there. In the UK, the video bandwidth of the analogue PAL signal is wider than in other PAL countries, which is why they had to move the sound subcarrier further from the vision carrier, and which is why TVs couldn't be taken to/from the UK from/to other PAL countries without some re-tuning, until multi-standard chipsets were introduced. It is very likely that he has never seen a PAL signal with as much resolution as we get in the UK.

Yes, I borrowed a digital PVR from a friend and was not at all impressed. I don't like it when the numerical noise sometimes stays still and sometimes moves. If they had not tried to cram so many channels of crap into the bandwidth then they could have made it as good as the analogue system. It's not like they have enough worthwhile programmes to fill even the analogue channels, so they could have afforded the bandwidth.

Chris

Reply to
Chris Jones

Of course there is DVB-T in the UK, that's why we know from personal experience that it looks worse than the old UK PAL system, that admittedly does have a wider video bandwidth than what you would have been used to.

Perhaps they have throttled down the bitrate per channel in the UK to less than they use where you are. I would like to see the numbers.

Or just someone who has seen both pictures and then tells the truth. I suspect that many people who have just spent a couple of grand on a new TV feel that they have to say it looks better, because otherwise that would make them stupid - so it's like the emperor's new clothes.

The more recent PAL TVs have fancy FIR comb filters that fix most of that stuff. It is certainly less intrusive than the DVB-T artefacts, like noise that freezes and then jumps and then freezes again.

And then buy another one when they switch to MPEG-4, which they have already proposed doing. Well by then it will have failed from tin whiskers anyhow.

Chris

Reply to
Chris Jones

I would like one which simultaneously decodes ALL OF the four main channels (BBC1, 2, ITV, CH4) and then re-modulates ALL of them as PAL onto different UHF frequencies, to basically recreate the old analog spectrum (albeit with some MPEG artefacts...). I want one of these because I'm pretty sure that I won't find a set top box that is as easy for my grandmother to use as the four-position rotary switch that is on her present TV, and I don't want it to be harder to use when the analogue transmitter is turned off. I think a box like that would sell very well even for a high price, to the elderly or basically to anyone who can't get that excited about a new modulation method like these fanboys, but who just wants to watch TV. Perhaps when the time comes I'll just have to buy 4 digiboxes and some splitters and combiners and make one of these boxes. At least then all her elderly neighbours could use it too, at the same time, so it might work out cheaper as well.

Chris

Reply to
Chris Jones

The reason that one might speculate this is that PbF solder has a higher melting point and is harder, thus perhaps less prone to thermal damaged due to cycling. This might be the case IF done right, but there are so many variables that it is impossible to generalize this. The fact is that most in the field realize that it is much easier to get it right with leaded solder, and it is generally considered to be more reliable for most applications. In fact, there are exemptions for critical applications that allow leaded solder, even in the EU. The biggest problem that I have seen in consumer electronics with PbF is that not enough solder is deposited in the automated process of making the boards. This aften leads to an unreliable joint. It is also harder to get good results in repairs with PbF, as it requires higher temperatures and even the most freindly formulations do not wet and flow as well.

Leonard

Reply to
Leonard Caillouet

And then just when it gets to the interesting part of the programme you're watching, outside it start raining. Then you get a few splutters of choppy audio and a blue screen, then nothing at all, and you have to wait for it to be repeated on analogue tomorrow.

Chris

Reply to
Chris Jones

Well I agree that there is no theoretical reason why the fact that the signal is digital necessarily makes it look bad, for example the PAL pictures that I have been watching were probably processed in the digital domain through most of the signal chain before transmission.

What I am comparing is the end-user experience of watching a consumer grade DVB-T receiver (in my case a Pioneer decoder), when compared to a consumer-grade PAL receiver. In the end, if the picture quality is worse USING THE EQUIPMENT AVAILABLE TO CONSUMERS, then that is all that counts. I realise that a digital system with 300Mbits per second could be much better than PAL, but what is being given to us is NOT better than PAL. By all means they could build a good digital system, but that is not what this is about. It is about freeing up as much spectrum as possible for auction, whilst enabling the maximum number of channels of adverts to be transmitted with a quality that is just good enough not to cause a backlash that would result in people just turning off and watching a DVD.

But surely you don't dispute that the channel bandwidth here is wider than what you used to get?

Well you just go and sit in your studio and watch your test cards then. What actually matters is the picture quality that people (don't) get in their homes.

Whatever.

Reply to
Chris Jones

Thank you, that's helpful.

I still think it might not be for grandmothers, e.g. explaining why you can't just unplug it when you're finished watching, etc. It would take me a day of driving to go and replace a failed HDD, and whilst the local TV shop can happily repair the analogue TV set, they might not be so hot on reinstalling perl scripts. At least the start-up time would not be unfamiliar, it would a reminder of waiting for the valves to warm up in the set before the present one (which was still working when it was scrapped, but it was 405 lines and B/W).

Chris

Reply to
Chris Jones

Of COURSE I have digital, foolish person. That is how I am able to comment on this. I have had analogue satellite since it was first available as DBS, and I changed over to digital as soon as that became available. I also still take analogue from the terrestrial transmissions, and carry out repairs to digital terrestrial STBs as part of my living, so I am able to compare all standards at all times. I feed signals around my house at UHF, and have perfectly clean signals at every TV - and there are a lot of them. As far as HDTV signals go, they just about manage to get back up to the standard of a *good* analogue transmission. As far as your opinion of my being inexperienced goes, I have been directly involved with this stuff from the service angle for 37 years. If that makes me 'inexperienced' in your eyes, sobeit.

As for beat interference atrifacts from tweed jackets and loud ties, this has not been much of a problem for years, since people in studios were dressed properly for the job. Even so, I would still rather see a 'busy' tie on a newsreader, than motion artifacts - both edge pixelation and motion blur - any day of the week.

It's all very well saying that compression artifacts are a product of available bandwidth, but that bandwidth is much limited with terrestrial digital, if you want to pack in the number of channels that they seem to want to. This allows for a perfectly satisfactory picture so long as it is standing still, but does not if the bitrate needs to go up high enough to prevent motion artifacts. For the most part, however, I would agree with you that this is not an issue with the satellite transmissions, where the limiting factor becomes how good a transponder, bit rate-wise, the station can afford to lease.

Make no mistake, I am not trying here to compare a good digital signal - say Sky Movies Premiere - with a poor noisy anlogue signal. What I am saying is that the general public is being 'sold a pup' with the digital terrestrial channels, where even the best quality transmissions, struggle to produce a picture subjectively as good as that produced on a *good* analogue TV with a

*good* analogue PAL signal going in.

Arfa

Reply to
Arfa Daily

I fear it is you who is the moron, my friend. It makes absolute sense to compare a crap digital signal to a good analogue one, for the ones provided by digital terrestrial are, for the most part, crap. This is in stark contrast to the analogue terrestrial signals, which have always been of the highest quality. The opinion of the poster on what he saw on a PVR, was not intended to be seen as a 'professional' test, rather it was a subjective test, which is what we have been talking here all along ...

Arfa

Reply to
Arfa Daily

data.

Another major issue is tin whiskers. We have hard evidence at $WeBuildAvionics (where I am currently consluting) that the current Pb Free / RoHS solder mixes have significant problems with growing whiskers, leading to wonderful issues such as short circuits developing under BGAs a few months after production. In a Flight control computer (don't laugh - in a fly by wire environment it's the ONLY flight control and virtually all late model airliners use it) this is Not a Good Thing [tm].

The whole RoHS / Pb free thing is a political issue - the processes for Pb Free use more hazardous substances than they get rid of.

Typical EU beauraucrats - unelected, overpaid and have to find something to regulate to justify their existence. [1]

Cheers

PeteS

[1] Their existence, even from birth, might not be justifiable.
Reply to
PeteS

Aha ! So you are comparing wide bandwidth high bit rate satellite transmissions, displayed on your high res PC screen, with an analogue PAL signal. That is not quite the same as a low bit rate highly compressed digital terrestrial transmission, displayed on an ordinary household TV set. I do not have an issue with a setup such as yours producing comparable - or even possibly superior in some instances - subjectively viewed pictures. But that was not the comparison that I was making, when I voiced the opinion that the digital pictures ( now being foisted on the public via the terrestrial TV transmission network ) did not compare to the analogue PAL pictures that we have been used to.

Arfa

Reply to
Arfa Daily

It's good to hear at last from someone involved in the avionics industry, and it's also good to hear that this particular industry is identifying serious problems with the technology, as that might at least help to maintain their exemption for some years to come. I really hope that the industry has sufficient strength to stand up to this legislation, and to continue to maintain their position of refusing to use it on safety / reliability grounds. With my daily dealings with lead-free solder, and all of the problems that it has brought to consumer electronics, the thought of being held seven miles up in the sky by equipment using the same technology, is truly worrying to me.

I cannot agree more that this whole thing is a poorly thought through example of 'bandwagon politics' and job justification.

I would be interested in hearing any other input that you may have on the subject, with regard to the avionics industry. Both anecdotal and factual would be welcome, and I am sure that Graham (who started this thread) would like see more from you, as well.

Arfa

Reply to
Arfa Daily

I agree with you.

The same holds for DAB too.

Graham

Reply to
Eeyore

I get regular breakups on cable, on multiple channels, at all times of day; picture plus sound, picture only, and sound only. Picture loss includes pixelization, cessation of action with partial pixelization, full loss of action for seconds at a time. A visit from the cable company can fix that for three or four days at a time.

The video reproduction is very reminiscent of the old 16-bit PC video cards, especially in low-light scenes when it starts to look like the video has about 16 brightness levels (four-bit video).

I used to get far better picture quality with rabbit ears from stations a hundred miles or more away. I can take the snow when I don't have to tolerate all the nasty artifacts in a digital picture.

--
"Liberals used to be the ones who argued that sending U.S. troops abroad
was a small price to pay to stop genocide; now they argue that genocide
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Reply to
clifto

You're an idiot, and have yet again said absolutely nothing.

Reply to
Spurious Response

Read it again. He said PROFESSIONAL, and NEWER equipment is inferred.

Reply to
Spurious Response

Spot on.

It is akin to a high end HD digital video card also carrying a composite output jack.

Reply to
Spurious Response

artefacts,

Since when did PROFESSIONALS not use PAL ?

Don't talk about stuff you have no experience of. It makes you look even more retarded than normal. I was the technical manager for an editing equipment hire company some years back. I do know what I'm talking about.

Broadcast TV isn't as wealthy as it once was and don't expect equipment to be 'upgraded' on a whim.

PAL (and especially UK PAL) produces a far superior picture to NTSC btw just in case you're getting confused.

Graham

Reply to
Eeyore

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