More bad digital TV news for Joerg?

DE-regulated? Are you insane? What's "You must pay your hard-earned money for this box to see TV any more" other than EXCESSIVE regulation?

Thanks, Rich

That may be, but just remember that a carrier may not have deployed all the technologies / spectrum available to it in that market on every tower. So, you might have a tower in your area that only offers one type of service. (i.e., CDMA, GSM, UMTS, etc..)

I do know there's about a 35 mile path limit to signalling on some local 3G systems. This has to do with the signalling times, and something deep down in the air-interface standard. I don't have the skinny on it, but can probably get it if you're interested.

Depending on who your carrier is, I can tell you who has what where. (except for in-building stuff.) -mpm

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Yes. Literally a bit of wet string in the socket can bring in good analogue TV!. ... I'm intrigued though by your mention of a possible built in diagnostics facility. My exertion so far has been discovering which button to press to change channels, so this evening I'll RTFM and have a poke about. Also my new digital TV PC tuner card barely sees anything at all. No overloading, tried the attenuator thing a while ago. Can also rotate the aerial off beam and onto other much weaker signals. I notice the digital signal is coming off Emley tower at only! 50kW c.f. the analogue power 870kW, so should maybe rationalise my problems to tropospheric non-ducting, non-sporadic E or some local meteor scattering :). Best thing is to wait for switchover, give it a couple days and then dump all the kit. Nothing worth watching anyway :)

On a sunny day (Tue, 21 Oct 2008 11:10:25 -0700) it happened Joerg wrote in :

GSM here does not 'always' work. I have for example an 'Orange' (that is service provider) GSM, and it did not really work here indoors. I called their helpdesk, and they told me: 'We do not guarantee indoor use'. So much for that :-) Am using it as PDA now..... The calender and alarm are great. For reliable GSM I have to climb the stairs, and phone from there. But I am way at the end of the world.

Then they should not market it. A disappointed customer rarely returns, ever. You typically get exactly one shot.

They are fiercely competing out here and I am sure they try their best to make sure it's all in place. There is nothing worse than unhappy customers especially since we now (finally!) have something like a

30-day cool-off period. IOW if it ain't working you can get out of the contract.

The towers are all within 1-2 miles, no tricky terrain. The terrain begins to become tricky about 20 miles from here towards where the TV stations are.

AFAIK it's 35km but can be increased in firmware.

He's got AT&T over GSM, I got Virgin via Sprint's CDMA network. And by golly, I am glad I made that choice. I can't even count anymore all the occasions where I had signal and others were looking at zero bars.

--
Regards, Joerg

http://www.analogconsultants.com/

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They don't go out of their way to advertise them. I don't think it is even in the mentioned in the manuals, but prodding around somewhere off the tuning or config menu there is a channel signal info display. Once it is enabled you can flick between channels and see whatever it chooses to display. Unfortunately the diagnostics are not as informative as they could be at least on the boxes that I possess (some are better than others). The oldest unit does skin tones clamped to grey when the signal is marginal before it breaks down completely. It is still the most sensitive of the units I have and fails last.

You might be able to run custom software like Jan's on that to get a real handle on what is going on here. Be glad you are not in the USA their dtv broadcast signal is even more prone to multipath problems.

Freesat ought to be OK for signal levels even if terrestrial is a dog... can't do much about the programming content though.

Regards, Martin Brown

It is pure market forces. You want to watch the TV in future you have to buy the box. A bit monopolistic I grant you. But if you want to receive the signal then you have to buy a receiver and decoder.

Regards, Martin Brown

So, should we all start wearing swastika armbands, marching the goose-step, and saying "Seig Heil" whenever we see a bureaucrat?

Thanks, Rich

Heh. My UHF antenna is a Radio Shack clip lead and a venetian blind. ;-)

Cheers! Rich

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The only person goosestepping here is you. You are not *compelled* to watch TV at all. Switch it off instead.

Regards, Martin Brown

the decendants of those who chose NTSC before colour TV was mature.

I think there's an element who want USA to be First, unfortunatly that means adopting as standards technology that's soon eclipsed.

Bye. Jasen

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witch

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I always believed that Never Twice (the) Same Color (sic) was well named and that the color instablity was an intrinsic problem with the modulation technology until I lived in Japan where they correctly implemented the NTSC specification. Flesh tones of US newscasters drifting between Addams family green and purple tinges was most entertaining. The improvement that clamped flesh tones to dead flesh orange was even funnier.

UK PAL is intrinsically insensitive to the same type of systematic error by design.

Strangely though the Japanese had some experimental HD TV broadcasting in the early 1990's. Mostly on demo screens in the larger store like Laox. The technology was eclipsed by digital but it was cute in its day. Lots of Japanese hitech toys do not make it out of the home market. you only hear about the winners.

When it works digital TV image quality is excellent but there are interference problems. Another which has recently come to light in the UK is that older cars with inadequate spark gap suppression and mopeds with magneto ignition seem to generate wideband interference right up into the GHz band. Loss of picture is in part correlated with mopeds going past - shades of "Local Hero".

Regards, Martin Brown

On a sunny day (23 Oct 2008 10:21:15 GMT) it happened Jasen Betts wrote in :

US never was first, here in the Netherlands we are 100% digital now for more then a year. Put my analog portable at the trash....

It was simply not wanting to use the better (from a multipath POV) European system.

Market protection, give US manufacturers a chance, although both the Europeans and US have the stuff made in China ;-)

It was not an intrinsic problem. Our NTSC color TV works just fine. Always did. We live in an area of heavy and time-varying multipath distortion yet the colors are always crisp and never run away.

And this _is_ in the US.

[...]

--
Regards, Joerg

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Really? After I used a spectrum analyzer to align my antenna, the picture on the screen is rock solid and the display on the analyzer is textbook. When I was having problems, it was indeed from multipath as you could watch the spectrum response changing with up to a 10 dB notch in the channel. My old receivers (Samsung SIR-T165 and 4 ATI HDTV Wonders) can deal with pretty bad static multipath but they aren't so good with dynamics.

Basically, I got the antenna high enough to clear the neighbors house across the street and give me a clear shot to Mt Wilson (LA). At our house, DTV is great.

GG

[...]

Lucky you. From here nobody ever has a clear shot unless they install a tower of a few hundred feet or happen to live perfectly in line with the cut DOT made at the Bass Lake grade for Hwy 50.

--
Regards, Joerg

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I wonder what kind of rate that is for the video frame rate and the per second audio rate.

This is beginning to sound like there were several errors made in error rate management. Perhaps even fundamental errors.

HD is about 2 megapixels of at least 24-bit video before compression. At a compression of about 20:1 it still represents 2e6*24*30/20 bits per second (72E6). The compression rate is actually like 100:1 thus on decompression it becomes 100 bit errors localized with the blocking factor of the compression algorithm. In both video and audio flagging and some post decompression process smoothing could help a lot.

Alas, the freezing and muted audio when the ber in the OTA signal degrades much past the 30 or so bits that would mangle a video frame or cause serious sonic disturbances. But this also represents something like a ber of 3e-6. Then use Shannon's law, the bit rate, and the bandwidth to figure our your minimum S/N ratio and thus maximum allowable path attenuation versus antenna gain. Use it again for a ber of 10e-9 (should produce near perfect reception).

Perhaps one or two single channel antennas, carefully pointed, and one general antenna.

Oh, dear little bubbela. This is what republicans have always meant with deregulation. Anyone with the financial resources to do volume manufacturing may make and sell the boxes. That is competition. Much of this dates further back to the first republican congressional majorities in the Slick WIllie era.

Absolutely. Now for how many years have all new receivers been required to be equipped with DTV receivers? Compare with historical life.