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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#81
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
"Jan Panteltje" wrote in message ... The one who calls himself rabbitsfriendsandrelations wrote: Jan Panteltje wrote: Eeyore wrote Jan Panteltje wrote: Spurious Response wrote Right, I turned in a portable TV last week. This one was about 30 years old (seventies), and was still working OK, but no analog transmissions here anymore, all you get is nice equal distributed noise when tuning in to a digital station. There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. The boxes that are sold here are equipped with a SCART connector, a waste. I imagine you haven't looked very hard in that case. Many have UHF outputs. Graham If you had as much as a clue, did not cut half the posting I wasn't replying to the bits I trimmed. Graham To enlighten the others: to buy anything with any sort of analog output sucks, as analog is dead at least here in the Netherlands (except for audio). Buying a settop box with USB output, if you have a laptop with USB, creates the portable TV with much better quality and recording possibility. The USB settop box I bought runs from a 12 V adapter, so also from a car battery. I researched quite a bit to get the best deal, and SCART was not part of that, let alone a horrible interference prone, PAL coding artefacts decorated UHF analog output. ftp://panteltje.com/pub/dvb-t-nl.txt You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. If you want to talk about a picture decorated in artefacts however, then digital is the hands down winner every time in that category ... Anyways, although your analogue terrestrial *transmissions* may have ceased, I think it is unlikely that everyone in Holland has just thrown all of their analogue-input ( both RF and composite ) portable TV sets and such in the bin, and as long as that is the case, there will still be a need for analogue outputs on other equipment such as STBs. Bear in mind also that an analogue signal does not need to be UHF modulated, to be PAL encoded. One of the default modes of the SCART standard is good old PAL-encoded analogue composite video, both input and output. Arfa |
#82
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
On a sunny day (Thu, 26 Jul 2007 16:35:53 GMT) it happened "Arfa Daily"
wrote in : To enlighten the others: to buy anything with any sort of analog output sucks, as analog is dead at least here in the Netherlands (except for audio). Buying a settop box with USB output, if you have a laptop with USB, creates the portable TV with much better quality and recording possibility. The USB settop box I bought runs from a 12 V adapter, so also from a car battery. I researched quite a bit to get the best deal, and SCART was not part of that, let alone a horrible interference prone, PAL coding artefacts decorated UHF analog output. ftp://panteltje.com/pub/dvb-t-nl.txt You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. Well, maybe you do not have digital yet. And for sure you have not seen the HDTV tests on satellite like those from France. I am not denying mpeg2 compression has artefacts, but those very much depend on bandwidth (bitrate), and bitrate is a bit less then 4000 kbps on digital here. (non HD). Although that is less then DVD max, it is absolutely enough for a stunning _noise free_, _moire free_ (PAL & NTSC composite), _easy to record_ (as .ts), _no loss editing_ (digital), _space saving_ (both on disk and in the ether), allowing as many sub-channels as you like (more languages, more subtitles, teletext, other services, timecode, all in the same stream). It seems to me you do not _HAVE_ digital yet. I have had digital sat now for about 7 years, and terrestrial for about a year. As to range an signal to noise, I can get stations that I could only get with a lot of noise and some reflections too in analog, now as clear as glass. Really, only an inexperienced person would claim that composite PAL in _whatever way_ was better. And I know composite PAL better then many of you here, as I worked many years at the source, Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) |
#83
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 17:10:00 GMT, in sci.electronics.design Jan
Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today martin |
#84
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
martin griffith wrote: On Thu, 26 Jul 2007 17:10:00 GMT, in sci.electronics.design Jan Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today Interesting you should say that. There must be tons of gear out there that's 'legacy' so-to-speak PAL. Graham |
#85
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 20:51:59 +0100, in sci.electronics.design Eeyore
wrote: martin griffith wrote: On Thu, 26 Jul 2007 17:10:00 GMT, in sci.electronics.design Jan Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today Interesting you should say that. There must be tons of gear out there that's 'legacy' so-to-speak PAL. Graham I think you can still buy toy composite mixers, try BHphoto etc and the camera control units (CCU) all had the usual PAL ScH and timing adjustments, but rarely used, and don't forget that the (almost obselete) Betacam SP format recorded in YUV anyway. The PAL outputs are great for preview monitors, ie non critical, and less wiring. PAL is a very robust transmission format, but absolutely sucks in a production setting martin |
#86
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
On a sunny day (Thu, 26 Jul 2007 22:55:42 +0100) it happened Chris Jones
wrote in : You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. Actually I think you may be speaking some truth there. No it is crap. In the UK, YUK 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, Yea, well known, BBC, before it went brain dead, used to make nice pictures, even had in the very old ages 4 tube cameras, I have been there, touched them, had some interesting discussions with their techies. Whatever you may think, compared to digital it sucks. And that is digital done the right way, it makes no sense to compare bad digital to HQ studio analog PAL as you do here when you talk about some cheapo unspecified piece of consumer quality, about some unspecified channels, sure you can get it as bad as you like. 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. Idiot. If you want to talk about a picture decorated in artefacts however, then digital is the hands down winner every time in that category ... Yes, I borrowed a digital PVR from a friend and was not at all impressed. Now that sure counts as a professional test. Morons. BYE |
#87
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Spurious Response wrote:
There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. Really? Could I have a model number and manufacturer? Every source I've seen says that to date there is absolutely no such thing in existence, and is pessimistic about the appearance of such before the deadline and/or at a price anywhere near the ridiculously low projections for price of such items. -- "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 is a small price to pay to bring U.S. troops home." -- Jonah Goldberg |
#88
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
On a sunny day (Thu, 26 Jul 2007 23:06:19 +0100) it happened Chris Jones
wrote in : Well, maybe you do not have digital yet. 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. Well, tehre are some channels 9I can tell you as ican get all UK stuff here too via satellite, tha tis ITV1-4 BBC- Parliament (if that is a channel), many more, and soem of teh FTA Ky. I have __***NEVER***__ seen 'noise stop', that is actually a sign of your decoder not keeping up, I have noticed that some Sky channels transmit in 352x288 (the set will scale it to full) so at 1/4 the bandwidth, but you cannot blame that on the digital system!!!!!! Blame it on Rupert!!! You are not talking about a f*cking Skybox no????????????????? And for sure you have not seen the HDTV tests on satellite like those from France. I am not denying mpeg2 compression has artefacts, but those very much depend on bandwidth (bitrate), and bitrate is a bit less then 4000 kbps on digital here. (non HD). 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. Exactly, there is, if you have a PCI card, some Linux program that shows all the bitrates for the various streams in the transponders. Cannot remember the name of the program, there are hundreds of utilities. Or just someone who has seen both pictures and then tells the truth. Sure, I do not question the observation, but I do say you need to compare GOOD digital with GOOD PAL composite, else comparing makes no sense. 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. Yes those pople may exist, but normal people would return the set. I say: Just buy a good digital set :-) 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. That is why I am using a PC, no matter how they encode it, I will find some decoder. The public will keep buying new stuf fevery standard change say maybe even more often then the lead-free requires. |
#89
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
On a sunny day (Thu, 26 Jul 2007 23:13:52 +0100) it happened Chris Jones
wrote in : Eeyore wrote: Jan Panteltje wrote: Spurious Response wrote Right, I turned in a portable TV last week. This one was about 30 years old (seventies), and was still working OK, but no analog transmissions here anymore, all you get is nice equal distributed noise when tuning in to a digital station. There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. The boxes that are sold here are equipped with a SCART connector, a waste. I imagine you haven't looked very hard in that case. Many have UHF outputs. 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 On my PC I have voice control, I can just say: show BBC1 show ITV1 show ARD show RAIuno and in a second or so (as the motorized dish moves to a different sat) I have it on the 1680x1050 LCD (no not yet 1980). All it needs is a PCI card and a satellite dish. Your granny could do it, if she could find the power button on the PC and monitor. You can find the scripts on my website (Linux of course). http://panteltje.com/panteltje/dvd/index.html login with user 'guest' and password 'none' without the quotes. http://panteltje.com/panteltje/dvd/show |
#90
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Glen Walpert wrote:
My nutshell summary of the published test results is that lead free is significantly harder to do right than tin-lead, requiring tighter process controls, but if done right it can be more reliable than tin-lead for non-shock situations. MORE reliable? Please elaborate. -- "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 is a small price to pay to bring U.S. troops home." -- Jonah Goldberg |
#91
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
martin griffith wrote: Eeyore wrote: martin griffith wrote: Jan Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today Interesting you should say that. There must be tons of gear out there that's 'legacy' so-to-speak PAL. I think you can still buy toy composite mixers, try BHphoto etc and the camera control units (CCU) all had the usual PAL ScH and timing adjustments, but rarely used, and don't forget that the (almost obselete) Betacam SP format recorded in YUV anyway. The PAL outputs are great for preview monitors, ie non critical, and less wiring. PAL is a very robust transmission format, but absolutely sucks in a production setting 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 |
#92
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Arfa Daily wrote:
"Jan Panteltje" wrote in message ... The one who calls himself rabbitsfriendsandrelations wrote: Jan Panteltje wrote: Eeyore wrote Jan Panteltje wrote: Spurious Response wrote Right, I turned in a portable TV last week. This one was about 30 years old (seventies), and was still working OK, but no analog transmissions here anymore, all you get is nice equal distributed noise when tuning in to a digital station. There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. The boxes that are sold here are equipped with a SCART connector, a waste. I imagine you haven't looked very hard in that case. Many have UHF outputs. Graham If you had as much as a clue, did not cut half the posting I wasn't replying to the bits I trimmed. Graham To enlighten the others: to buy anything with any sort of analog output sucks, as analog is dead at least here in the Netherlands (except for audio). Buying a settop box with USB output, if you have a laptop with USB, creates the portable TV with much better quality and recording possibility. The USB settop box I bought runs from a 12 V adapter, so also from a car battery. I researched quite a bit to get the best deal, and SCART was not part of that, let alone a horrible interference prone, PAL coding artefacts decorated UHF analog output. ftp://panteltje.com/pub/dvb-t-nl.txt You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. 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. If you want to talk about a picture decorated in artefacts however, then digital is the hands down winner every time in that category ... 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 |
#93
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Jan Panteltje wrote:
On a sunny day (Thu, 26 Jul 2007 16:35:53 GMT) it happened "Arfa Daily" wrote in : To enlighten the others: to buy anything with any sort of analog output sucks, as analog is dead at least here in the Netherlands (except for audio). Buying a settop box with USB output, if you have a laptop with USB, creates the portable TV with much better quality and recording possibility. The USB settop box I bought runs from a 12 V adapter, so also from a car battery. I researched quite a bit to get the best deal, and SCART was not part of that, let alone a horrible interference prone, PAL coding artefacts decorated UHF analog output. ftp://panteltje.com/pub/dvb-t-nl.txt You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. Well, maybe you do not have digital yet. 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. And for sure you have not seen the HDTV tests on satellite like those from France. I am not denying mpeg2 compression has artefacts, but those very much depend on bandwidth (bitrate), and bitrate is a bit less then 4000 kbps on digital here. (non HD). 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. Although that is less then DVD max, it is absolutely enough for a stunning _noise free_, _moire free_ (PAL & NTSC composite), _easy to record_ (as .ts), _no loss editing_ (digital), _space saving_ (both on disk and in the ether), allowing as many sub-channels as you like (more languages, more subtitles, teletext, other services, timecode, all in the same stream). It seems to me you do not _HAVE_ digital yet. I have had digital sat now for about 7 years, and terrestrial for about a year. As to range an signal to noise, I can get stations that I could only get with a lot of noise and some reflections too in analog, now as clear as glass. Really, only an inexperienced person would claim that composite PAL in _whatever way_ was better. 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. And I know composite PAL better then many of you here, as I worked many years at the source, Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. 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. I say: Just buy a good digital set :-) 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 |
#94
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Eeyore wrote:
Jan Panteltje wrote: Spurious Response wrote Right, I turned in a portable TV last week. This one was about 30 years old (seventies), and was still working OK, but no analog transmissions here anymore, all you get is nice equal distributed noise when tuning in to a digital station. There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. The boxes that are sold here are equipped with a SCART connector, a waste. I imagine you haven't looked very hard in that case. Many have UHF outputs. 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 |
#95
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
"clifto" wrote in message ... Glen Walpert wrote: My nutshell summary of the published test results is that lead free is significantly harder to do right than tin-lead, requiring tighter process controls, but if done right it can be more reliable than tin-lead for non-shock situations. MORE reliable? Please elaborate. 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 |
#96
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Spurious Response wrote:
On Thu, 26 Jul 2007 02:37:53 +0100, Eeyore wrote: Spurious Response wrote: Eeyore wrote: Spurious Response wrote: What is nice about digital broadcasts is that when you have the signal, you have it all. No snow, No herringbone patterns. Crisp and clean, with no caffeine. Except when it breaks up. Nope. If you tune the signal, you get ALL of the data. You must exceed more than ten percent bit error rate for a dropout to occur, and it is bit error rate that matters most for a "tuned" channel. I have a cable TV set top box. There's no tuning involved. It still breaks up occasionally. IT tunes itself, dip****. Do you actually think I meant that you had a knob to turn? Get your head out of your twenty year behind the digitally tuned receiver world ass. OK... I'll spell it out for you. If it ACQUIRES the signal, and locks it in, it gets ALL packets from the HEAVILY FEC coded stream, and can handle up to a 10% bit error rate before the "tuning" starts to lose, and not be able to repair with the FEC, data packets. When that happens, one starts to lose audio and or video or could see some video artifacts. It usually results in short term. low frame count dropouts. So it isn't "breaking up". That is an analog expression. In digital broadcast streams, the term is "dropout". 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 |
#97
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Jan Panteltje wrote:
On a sunny day (Thu, 26 Jul 2007 22:55:42 +0100) it happened Chris Jones wrote in : You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. Actually I think you may be speaking some truth there. No it is crap. In the UK, YUK 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, Yea, well known, BBC, before it went brain dead, used to make nice pictures, even had in the very old ages 4 tube cameras, I have been there, touched them, had some interesting discussions with their techies. Whatever you may think, compared to digital it sucks. And that is digital done the right way, it makes no sense to compare bad digital to HQ studio analog PAL as you do here when you talk about some cheapo unspecified piece of consumer quality, about some unspecified channels, sure you can get it as bad as you like. 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. 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. Idiot. But surely you don't dispute that the channel bandwidth here is wider than what you used to get? If you want to talk about a picture decorated in artefacts however, then digital is the hands down winner every time in that category ... Yes, I borrowed a digital PVR from a friend and was not at all impressed. Now that sure counts as a professional test. 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. Morons. BYE Whatever. |
#98
Posted to sci.electronics.design,sci.electronics.repair
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So what's the truth about lead-free solder ?
Jan Panteltje wrote:
On a sunny day (Thu, 26 Jul 2007 23:13:52 +0100) it happened Chris Jones wrote in : Eeyore wrote: Jan Panteltje wrote: Spurious Response wrote Right, I turned in a portable TV last week. This one was about 30 years old (seventies), and was still working OK, but no analog transmissions here anymore, all you get is nice equal distributed noise when tuning in to a digital station. There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. The boxes that are sold here are equipped with a SCART connector, a waste. I imagine you haven't looked very hard in that case. Many have UHF outputs. 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 On my PC I have voice control, I can just say: show BBC1 show ITV1 show ARD show RAIuno and in a second or so (as the motorized dish moves to a different sat) I have it on the 1680x1050 LCD (no not yet 1980). All it needs is a PCI card and a satellite dish. Your granny could do it, if she could find the power button on the PC and monitor. You can find the scripts on my website (Linux of course). http://panteltje.com/panteltje/dvd/index.html login with user 'guest' and password 'none' without the quotes. http://panteltje.com/panteltje/dvd/show 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 |
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So what's the truth about lead-free solder ?
"Jan Panteltje" wrote in message ... On a sunny day (Thu, 26 Jul 2007 16:35:53 GMT) it happened "Arfa Daily" wrote in : To enlighten the others: to buy anything with any sort of analog output sucks, as analog is dead at least here in the Netherlands (except for audio). Buying a settop box with USB output, if you have a laptop with USB, creates the portable TV with much better quality and recording possibility. The USB settop box I bought runs from a 12 V adapter, so also from a car battery. I researched quite a bit to get the best deal, and SCART was not part of that, let alone a horrible interference prone, PAL coding artefacts decorated UHF analog output. ftp://panteltje.com/pub/dvb-t-nl.txt You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. Well, maybe you do not have digital yet. And for sure you have not seen the HDTV tests on satellite like those from France. I am not denying mpeg2 compression has artefacts, but those very much depend on bandwidth (bitrate), and bitrate is a bit less then 4000 kbps on digital here. (non HD). Although that is less then DVD max, it is absolutely enough for a stunning _noise free_, _moire free_ (PAL & NTSC composite), _easy to record_ (as .ts), _no loss editing_ (digital), _space saving_ (both on disk and in the ether), allowing as many sub-channels as you like (more languages, more subtitles, teletext, other services, timecode, all in the same stream). It seems to me you do not _HAVE_ digital yet. I have had digital sat now for about 7 years, and terrestrial for about a year. As to range an signal to noise, I can get stations that I could only get with a lot of noise and some reflections too in analog, now as clear as glass. Really, only an inexperienced person would claim that composite PAL in _whatever way_ was better. And I know composite PAL better then many of you here, as I worked many years at the source, Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) 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 |
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So what's the truth about lead-free solder ?
"Jan Panteltje" wrote in message ... On a sunny day (Thu, 26 Jul 2007 22:55:42 +0100) it happened Chris Jones wrote in : You must have some rubbish kit over there then. A good PAL analogue TV set, with a decent signal going in, beats a crappy highly compressed digital signal, hands down, every time. Actually I think you may be speaking some truth there. No it is crap. In the UK, YUK 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, Yea, well known, BBC, before it went brain dead, used to make nice pictures, even had in the very old ages 4 tube cameras, I have been there, touched them, had some interesting discussions with their techies. Whatever you may think, compared to digital it sucks. And that is digital done the right way, it makes no sense to compare bad digital to HQ studio analog PAL as you do here when you talk about some cheapo unspecified piece of consumer quality, about some unspecified channels, sure you can get it as bad as you like. 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. Idiot. If you want to talk about a picture decorated in artefacts however, then digital is the hands down winner every time in that category ... Yes, I borrowed a digital PVR from a friend and was not at all impressed. Now that sure counts as a professional test. Morons. BYE 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 |
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So what's the truth about lead-free solder ?
Glen Walpert wrote:
On Tue, 24 Jul 2007 23:42:47 +0100, Eeyore wrote: The debate about lead free solders seem to be nearly as politically charged as that about anthropogenic global warming and a casualty seems to be useful data. I've read plenty of comments to the effect that lead-free is less reliable in the long term (vibration seems to be a key weakness AIUI - maybe also thermal cycling) which presumably explains the exemptions for certain categories, yet I've also seen some studies that claim it can out-perform lead containing solders. Is there any real hard and fast information out there that one can rely on ? Graham Don't look to this newsgroup for factual info on lead free! Instead look at actual test results in the trade publications such as SMT magazine: http://smt.pennnet.com/home.cfm They have published numerous tests comparing various lead free materials and processes with tin-lead. Some lead free materials and processes are better than others (no surprise) and picking the best one for your situation is non-trivial. My nutshell summary of the published test results is that lead free is significantly harder to do right than tin-lead, requiring tighter process controls, but if done right it can be more reliable than tin-lead for non-shock situations. Lead free is harder, stronger and more brittle than tin-lead so tin-lead will deform plastically under high shock when lead free will break, however lead free will withstand more hot-cold cycles than before failure than tin-lead (better fatigue resistance). So you need to know what the significant failure mechanisms are in your design to pick the most reliable materials. Glen 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. |
#102
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So what's the truth about lead-free solder ?
On my PC I have voice control, I can just say: show BBC1 show ITV1 show ARD show RAIuno and in a second or so (as the motorized dish moves to a different sat) I have it on the 1680x1050 LCD (no not yet 1980). All it needs is a PCI card and a satellite dish. 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 |
#103
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So what's the truth about lead-free solder ?
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. 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 |
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So what's the truth about lead-free solder ?
Arfa Daily wrote: 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. I agree with you. The same holds for DAB too. Graham |
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So what's the truth about lead-free solder ?
Spurious Response wrote:
wrote: Spurious Response wrote: What is nice about digital broadcasts is that when you have the signal, you have it all. No snow, No herringbone patterns. Crisp and clean, with no caffeine. Except when it breaks up. Nope. If you tune the signal, you get ALL of the data. You must exceed more than ten percent bit error rate for a dropout to occur, and it is bit error rate that matters most for a "tuned" channel. 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 is a small price to pay to bring U.S. troops home." -- Jonah Goldberg |
#106
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 13:24:13 +0100, Eeyore
wrote: Spurious Response wrote: Eeyore wrote: Spurious Response wrote: So it isn't "breaking up". Yes it 'breaks up'. Typically with weird pixellation. That is an analog expression. No it isn't. In digital broadcast streams, the term is "dropout". No, a dropout is a momentary LOSS of signal. No. In HDTV broadcast, "dropout" is when a tuned station has more than about 10% bit error rate, and the FEC cannot repair the data stream, and everything from a few picture artifacts appears, to complete frame losses (dropouts) occur. The picture artifacts are also dropouts, just not those that cause the tuning device to display a blank screen for that given frame, which they do when it gets beyond a certain point. If they wanted to, they could show you the frames, and you would see horrendous amounts of image artifacts, and likely audio problems as well. It IS called dropout. Lost packets ARE lost "signal" as the packet would not have been lost, were it not for the tuner's inability to reconstruct any missing packet data from the FEC coding. This has been true from way back in the early satellite receiver days. Videocipher http://en.wikipedia.org/wiki/Videocipher Digicipher II (most closely related to the new HDTV broadcast schema). http://en.wikipedia.org/wiki/DigiCipher_2 The current HDTV broadcast schema is also a General Instrument format, now owned by Motorola. Thanks for playing. It is like taking candy from a baby though. You're an idiot, and have yet again said absolutely nothing. |
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 20:51:59 +0100, Eeyore
wrote: martin griffith wrote: On Thu, 26 Jul 2007 17:10:00 GMT, in sci.electronics.design Jan Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today Interesting you should say that. There must be tons of gear out there that's 'legacy' so-to-speak PAL. Read it again. He said PROFESSIONAL, and NEWER equipment is inferred. |
#108
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 22:35:45 +0200, martin griffith
wrote: On Thu, 26 Jul 2007 20:51:59 +0100, in sci.electronics.design Eeyore wrote: martin griffith wrote: On Thu, 26 Jul 2007 17:10:00 GMT, in sci.electronics.design Jan Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today Interesting you should say that. There must be tons of gear out there that's 'legacy' so-to-speak PAL. Graham I think you can still buy toy composite mixers, try BHphoto etc and the camera control units (CCU) all had the usual PAL ScH and timing adjustments, but rarely used, and don't forget that the (almost obselete) Betacam SP format recorded in YUV anyway. The PAL outputs are great for preview monitors, ie non critical, and less wiring. PAL is a very robust transmission format, but absolutely sucks in a production setting Spot on. It is akin to a high end HD digital video card also carrying a composite output jack. |
#109
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So what's the truth about lead-free solder ?
Spurious Response wrote: Eeyore wrote: martin griffith wrote: Jan Panteltje wrote: Even studio quality (directly from a PAL camera) has all sorts of artefacts, just where the right striped shirt. I say: Just buy a good digital set :-) Hmm, all the pro cameras I know come out in RGB or YUV. Nobody in the professional world should be using PAL/NTSC in the studio's primary signal chain today Interesting you should say that. There must be tons of gear out there that's 'legacy' so-to-speak PAL. Read it again. He said PROFESSIONAL, and NEWER equipment is inferred. 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 |
#110
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 16:18:00 -0500, clifto wrote:
Spurious Response wrote: There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. Really? Could I have a model number and manufacturer? US Digital. WalMart. Made by Hisense, model DB-2010. ($200) Broadcast only, NOT capable of the cable format. Ready for a single antenna, multi-channel subscriber reception planned for the future in some cities. Every source I've seen says that to date there is absolutely no such thing in existence, and is pessimistic about the appearance of such before the deadline and/or at a price anywhere near the ridiculously low projections for price of such items. It has been out for over two years now, and it looks amazing on an old standard set, not to mention on an actual HD set. Broadcast digital reception is flawless, and should be the standard... Oooops... to late... It is! It has component out and composite, and SVHS. Two channel audio only. Great reception with either a standard set top antenna or a preamplified unit, not to mention a rooftop job. The "several" remark was just an assumption, but one would think that others would include such a feature in their units. |
#111
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 16:39:50 -0500, clifto wrote:
Glen Walpert wrote: My nutshell summary of the published test results is that lead free is significantly harder to do right than tin-lead, requiring tighter process controls, but if done right it can be more reliable than tin-lead for non-shock situations. MORE reliable? Please elaborate. SHOCK.... and AWE! |
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 23:31:48 GMT, "Arfa Daily"
wrote: It's all very well saying that compression artifacts are a product of available bandwidth, but that bandwidth is much limited with terrestrial digital, Both terrestrial broadcast, as well as satellite uplinks are 6MHz wide STANDARD channel slots and transponder slots. That was one of the rules of the game back when all this started. So, on "terrestrial", one can expect the best picture, as it is "single channel per carrier" (SCPC), whereas a satellite uplink from a service provider is going to be a "multiple channel per carrier" (MCPC) implementation, in 99.9999% of the cases. Artifacts are a product of bit error rate. If the bit error rate of your reception in zero, you WILL get ALL of the data. The other source of artifacts are pre transmission compression. In the old MCPC setup, only 6 or 10 channels per carrier could be pumped, and it was an MPEG-2 compression schema and a 480i schema. Now, they put up to 12 channels per carrier (per transponder) into the uplink for 24 or 64 channels per transponder total. With HDTV, much more data per frame needs to be dealt with. FEC is your friend. |
#113
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 23:31:48 GMT, "Arfa Daily"
wrote: For the most part, however, I would agree with you that this is not an issue with the satellite transmissions, Bull****. That is EXACTLY where the multiple channel per carrier thing gets implemented. In terrestrial schemes, it is only ONE channel per 6MHz wide carrier. Your tuner may say that there are 3 PBS channels on the number 15, but the actual frequencies of those channels are all on separate 6MHZ wide slots with MAYBE only one which as actually on the channel 15 assigned frequency. |
#114
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So what's the truth about lead-free solder ?
Spurious Response wrote:
On Thu, 26 Jul 2007 16:18:00 -0500, clifto wrote: Really? Could I have a model number and manufacturer? US Digital. WalMart. Made by Hisense, model DB-2010. ($200) Broadcast only, NOT capable of the cable format. Ready for a single antenna, multi-channel subscriber reception planned for the future in some cities. Thanks. I'll have to take a look. Broadcast digital reception is flawless, and should be the standard... Oooops... to late... It is! HDTV sucks, at least the little I've seen. The artifacts are too distracting for me to watch the picture. When you can get a camera to stand still while focused on a still object, so the compression isn't blurring everything, there's improvement in sharpness and no snow and, if you're lucky, a minimum of aliasing. When you get off the still life and start watching conventional programming, the picture goes to hell. I watched a bit of a football game while sitting in a furniture store and got a headache from seeing the crowd go into and out of focus. Great reception with either a standard set top antenna or a preamplified unit, not to mention a rooftop job. Wouldn't do me any good. I couldn't get a permit for the fifty-foot tower I couldn't afford to put up. Far too many buildings between me and the transmitting antennas at Sears Tower. -- "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 is a small price to pay to bring U.S. troops home." -- Jonah Goldberg |
#115
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So what's the truth about lead-free solder ?
Spurious Response wrote: "Arfa Daily" wrote: For the most part, however, I would agree with you that this is not an issue with the satellite transmissions, Bull****. That is EXACTLY where the multiple channel per carrier thing gets implemented. In terrestrial schemes, it is only ONE channel per 6MHz wide carrier. Your tuner may say that there are 3 PBS channels on the number 15, but the actual frequencies of those channels are all on separate 6MHZ wide slots with MAYBE only one which as actually on the channel 15 assigned frequency. 'Arfa' is in the UK. There is no 'PBS' here. We do have the BBC though, although it's been degraded terribly in the last few years on the cross of 'political correctness'. Graham |
#116
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Spurious Response wrote:
On Thu, 26 Jul 2007 16:39:50 -0500, clifto wrote: Glen Walpert wrote: My nutshell summary of the published test results is that lead free is significantly harder to do right than tin-lead, requiring tighter process controls, but if done right it can be more reliable than tin-lead for non-shock situations. MORE reliable? Please elaborate. SHOCK.... and AWE! Aw, not so shocking. -- "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 is a small price to pay to bring U.S. troops home." -- Jonah Goldberg |
#117
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 23:31:48 GMT, "Arfa Daily"
wrote: 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. You must be in a different multiverse location. Satellite service gives you 300 plus channels by putting up to 12 6MHz wide "channels" into each 6MHz wide slot. http://www.tech-faq.com/mcpc.shtml http://www.webopedia.com/TERM/M/MCPC.html |
#118
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 19:56:31 -0400, PeteS wrote:
Glen Walpert wrote: On Tue, 24 Jul 2007 23:42:47 +0100, Eeyore wrote: The debate about lead free solders seem to be nearly as politically charged as that about anthropogenic global warming and a casualty seems to be useful data. I've read plenty of comments to the effect that lead-free is less reliable in the long term (vibration seems to be a key weakness AIUI - maybe also thermal cycling) which presumably explains the exemptions for certain categories, yet I've also seen some studies that claim it can out-perform lead containing solders. Is there any real hard and fast information out there that one can rely on ? Graham Don't look to this newsgroup for factual info on lead free! Instead look at actual test results in the trade publications such as SMT magazine: http://smt.pennnet.com/home.cfm They have published numerous tests comparing various lead free materials and processes with tin-lead. Some lead free materials and processes are better than others (no surprise) and picking the best one for your situation is non-trivial. My nutshell summary of the published test results is that lead free is significantly harder to do right than tin-lead, requiring tighter process controls, but if done right it can be more reliable than tin-lead for non-shock situations. Lead free is harder, stronger and more brittle than tin-lead so tin-lead will deform plastically under high shock when lead free will break, however lead free will withstand more hot-cold cycles than before failure than tin-lead (better fatigue resistance). So you need to know what the significant failure mechanisms are in your design to pick the most reliable materials. Glen 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. Damn. You actually made a post that I agree with 100%. Seems one must fully encapsulate a finished assembly in transformer varnish under vacuum to lock out the whisker growth. Serviceability... right out the door. Stink factor... worse than it was. The whole ****ing thing stinks. |
#119
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 20:03:01 -0500, clifto wrote:
I get regular breakups on cable, on multiple channels, at all times of day; picture plus sound, picture only, and sound only. That is your fault for not calling them and complaining about your obviously poor strength feed. That or the dopes actually think they can send it out that way from the head end to everyone. That would be really sad, and point toward the need for a class action suit. started at a town meeting, and including the City Manager. |
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So what's the truth about lead-free solder ?
On Thu, 26 Jul 2007 20:03:01 -0500, clifto wrote:
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). That is referred to as "posterization". Remember posters that were of "photos" or "pictures", but could only give you a 16 color palette? Distinct lines of separation to "create" a gradient. |
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