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Author Topic: Digital Switchover  (Read 9554 times)

roseway

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Re: Digital Switchover
« Reply #30 on: September 28, 2011, 11:53:51 AM »

Very impressive 7LM. I built a MythTV media center a couple of years ago, and its features were great, but it didn't really fit in with my ways, so I didn't keep it. I considered adding satellite to it, but at the time there was no practical way to use a Sky viewing card with it, so it would only receive the free-to-air channels.
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  Eric

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Re: Digital Switchover
« Reply #31 on: September 28, 2011, 04:27:36 PM »

Very impressive 7LM.

IMPRESSIVE ?..... :swoon:

Puts Sky's Multiroom to shame doesn't it !!

I presume 7LM is the only person allowed to touch this creation ?......although you're probably the only person who knows how to operate it more likely  ;D
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sevenlayermuddle

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Re: Digital Switchover
« Reply #32 on: September 28, 2011, 07:33:09 PM »

I presume 7LM is the only person allowed to touch this creation ?......although you're probably the only person who knows how to operate it more likely  ;D

Usability is not to bad.  The frontends use lirc ( www.lirc.org ), which allows you to find any remote control that has all your favourite buttons on it, and then 'train' the system to recognise it.  Thereafter, it all behaves much like any other TV gadget, with some basic and intuitive menus to guide you.  But I admit I was both surprised and relieved back in the early summer when Mum was ill and I had to go up North, to find that Other Half not only been able to watch the some stuff I'd already recorded for her benefit, she'd even figured out how to schedule more recordings.

The real problem would arise if it ever broke, and I wasn't around to fix it.   Like a few months ago, when a LAN router went a bit ropey.  Or supposing the server's disk crashes, then a complete reinstall of Linux would be needed, plus a reinstall and reconfiguration of mythtv... and that's not for the faint hearted.  But I've tried to make sure that, in the event I were run over by a bus, all she need do is disconnect all computers and she'd be left with basic, but perfectly functional, conventional TV sets fed from the aerial sockets.   :)
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sevenlayermuddle

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Re: Digital Switchover
« Reply #33 on: September 30, 2011, 10:21:39 AM »

Hmm,  things are not as rosy as I first thought, the BBC channels have been degrading badly just after 9pm each evening.  That problem started just after the first phase of switchover two weeks ago, then resolved itself after a couple of days.  But it's returned with the second phase, and is much worse.

It makes me wonder if they may be tweaking the signal strengths to avoid interference with neighbouring areas.  I also can't help wondering if the transmitters may perhaps be set to change power at different times of day, which might explain the phenomenon others have reported of very transient break-ups, at very specific times, as the receiver's gain control mechanisms reacclimatise to the new signal strength.  That's just vague a theory of mine, I've found no evidence to support it.   :)

Of interest, digital TV employs very similar technology to ADSL, with Reed-Solomon Forward Error Correction, and an interleaved data stream.   As long as errors are being corrected all is well but, as soon as uncorrectable errors arise, the picture will start pixelating.  That does mean that many people who are receiving a 'perfect' picture may be unaware that there is actually a significant underlying error rate is still taking place, but getting corrected by reed-solomon.  Then, if the error rate gets just a little bit worse, some of them will go uncorrected  leading to the sudden deterioration from 'perfect' to 'awful'

« Last Edit: September 30, 2011, 10:27:27 AM by sevenlayermuddle »
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sevenlayermuddle

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Re: Digital Switchover
« Reply #34 on: October 04, 2011, 11:35:37 PM »

On the off chance anybody's still following this thread (?)

FWIW, I may have partially solved my reception problems by fitting an attenuator.  The trick was to fit it at the input to the distribution amplifier in the loft, rather than the input to individual TVs and tuners.  I suppose it makes sense, the signals from aerial got stronger post DSO, and were enough to swamp the input stages of the distribution amp.    I wonder how many people are digging themselves into deeper and deeper holes by following the old school of thought... 'bad reception, need better aerial', when in fact what they need is a 'worse' aerial (or at least an attenuator).

As another note, if you're eagerly awaiting the HD broadcasts, don't hold your breath.  Picture quality on true HD broadcasts is very impressive, but much or most of the BBC1 HD is just 'upscaled' which means the picture will be little better than produced by your own TV or PVR, as all recent TVs and recorders already contain quite good upscalers.  And worse, all the HD channels have prominent station logos.  BBC one, BBC HD and ITV HD logos are very distracting although you do get used to them (a light shade of grey).  But channel 4's HD logo is a prominent bright white that rather ruins the viewing experience, for me at least.  I just watched a channel 4 HD recording and think their logo may now be permanently etched into my retinas.    :(



« Last Edit: October 04, 2011, 11:50:08 PM by sevenlayermuddle »
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roseway

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Re: Digital Switchover
« Reply #35 on: October 05, 2011, 06:55:41 AM »

Overloading the distribution amplifier is quite a plausible theory, and I wouldn't be surprised if it causes grief for a lot of people. It's also going to be difficult to track during the changeover period, because transmitter power levels are going to be tweaked for the best compromise between signal levels and interference with neighbouring areas.

On the subject of HD, I'm not too surprised about the intrusive logos, because it's being pushed really hard by broadcasters and equipment suppliers, and the logo is a sort of badge for people to display to say they've got it. In many cases the logo will be the only way to know that a broadcast is in HD, because at normal viewing distance on normal size screens the improvement in resolution won't be discernible.
« Last Edit: October 05, 2011, 07:01:31 AM by roseway »
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  Eric
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