All posts by Robert
Below are all of Robert's postings, with the most recent are at the bottom of the page.
rebecca damm: Mike Davision is right with the solution he states but there are two other solutions one high cost, one low cost.
The high cost solution is to buy a hard disc recorder not sometime know as PVR instead of the digi box. If your TV is HD ready, you could by a PVR with one or more HD tuners inside and go HD at the same time. You then will able to record TV onto the hard disc with minimum fuss using the PVRs EPG. Buying a PVR with an HTMI output would be a good idea as even if you current TV does not have one, your next will and will give you better quality of picture over a SCART connection. You could still can record to tape by connecting the PVR (SCART) on the VCR This does not have to be done at the time of broadcast. I would also give you the flexibility to record all you favourite programs over the week that you are away on holiday. I see at least three clear benefits over Mikes solution.
The low cost method it to use the TV as the source of the Freeview video signal. TV can be setup to send a video output down the SCART to the VCR which can be told to record it but there are drawbacks getting it setup is one, you would only be able record what you were watching, you would have to leave the TV on, and on the correct channel to record your favourite program to watch later, if you were out at the time of broadcast. Manual programming is a pain and error prone.
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cathy: Six visits and you don't buy what your being told. Your can go and buy an new TV but I do not expect that to make any difference either. Neatly, their digibox would no longer be used.
Check out if her friends (espicially if they used the DigitalUK service too) and neighbours (new reception problems since DSO?). Are they seeing similar problems?
How many times have they changed the Digibox?, have they tried a different model?
Go back and talk to the service manager. Post again if you not happy with what you are told or think you have been fogged off.
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jb38: Loop under construction but I have done some back to back testing. I was getting problem on PVR but in bedroom a indoor Yagi, spare digibox and 9" monitor video was good. I then connect PVR to yagi. and moved digibox + monitor and connected to 'suspect' aerial in living room. My hope was that I would get a workaround by using a 'remote' aerial but this afternoon during rain, PVR was having problem yet monior was error free. Therefore it appears up-scalling via HDMI is now an issue post DSO and PVR records up-scalled version to hard drive.
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jb38: Thank you for your invalueable help but Sorry you are getting too focused on my equipment.I used indoor aerials but I have data from 3 three seperate communial aerial systems. All that appear to suffer in same way and conformation that this is new problem, linked to DSO and when it rains.
Everyone I've talked too in my block (who uses CP) has seen intermittent reception problems. That is seven households. Two people in two different blocks to mine have a 'carbon copy' of my problem.
Arqiva made a large number of changes all at the same time any one of which could have introduced an intermittent problem. Each one increases the technical risk of the project which I think were huge the more I read, the more I would panic.
Even if I was sucessful following your advice, digital TV in this area could only be described as unbelievably flaky.
I've got a meeting on Monday which might put this one on a professional footing.
My PVR is a Panasonic DMR-BW780 but My TV Samsung LE40C530F1N agrees even if it does not get so upset at the bad RF it decodes fom its own aerial. The remote aerial test are inconclusive at the moment.
I recorded 700 hrs of perfect video between Oct 2011 when PVR/Aerial configuration was setup and 3 April 2012.
I begining to think there are two different intermittent problems. I need to 'white box' a digital tuner, I can only black box test at the moment.
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Stephen P: It could be it is doing an automatic standby but why now? Have a look around the menus see if it has such a feature and if that could be the cause. Bad PSUs are a fact of life because everything built to a price, lots devices share the same electronic units inside, like power supplies. Is it getting hot and needs better ventilation? might have thermal shutdown built in.
Your best way forward is to google the Wharfdale model number and see if you pick up on a discussion thread. Treat the information it witn a bit of caution an expert can be caught out because of a querk in design of that model may invidates he general 'good' advice.
Google the problem, prehaps try with 'Wharfdale' added
If you can discover a 'firmware revision' google just that code. See what you get.
If you nifty with a screew driver and careful with mains electricity, have a look inside and see if you can find any code numbers and google them.
This is all about detective work and tapping into people who know more (maybe)or can show a path to solution.
It all about how many hits come back to any interenet search, too many or too few and relevance to the problem.
Use the internet and read with caution.
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Val Tilley: As a TV/Video amateur with a computer background what I understand is Error Pixels or block on the screen start to appear when the block of data which make up the video audio stream come through with uncorrectable (unrecoverable) data errors due to too much noise or interference on the modulated UHF signal from the aerial.
Digital transmission is fault tolerant, you can have a degree of noise or interference but it has to be within the bounds of the error correction circuits. This is its greatest strength. Your tuner not only knows the data is damaged but can correct it so the picture and sound generate are perfect so you never know but looking at the TV.
However, the fact the data had to be corrected is reported in the statistics used for either Signal Quality or bit rate error. This is a feature most tuner have somewhere in their menu structure.
Missing channel 12 (Yesterday) probably means that your tuner failed to find one of the Multiplexers. Crystal Palace transmits all TV and radio over six multiplexers. To check I my tuner has found each one I should have BBC1 (1), ITV1 (3), ITV3 (10), Pick TV(11), Yesterday (12) and BBC1HD(50). Information on what TV station is on what Mux is explained elsewhere on the website but BBC2 shares with BBC1, ITV1 shares with Channel 4 & 5.
My recent experience with automatic scanning suggest that it is not very fault tolerant. The TV's tuner had a perfect picture yet the PVR which I was tuning missed the Mux. I was just manually tuning the Mux with ITV1 on it yet Channel 4 and Channel 5 were not in the list yet worked if I tapped 4 or 5 on the remote. So not very robust either.
Missing muxes are a common problem if you were setting up to watch Freeview via an indoor aerial but prior to DSO finding the sweet spot for the aerial was a 5 or 10 minute task once found it was reliable. I never knew there were seven muxes before DSO because I did not have to be able to diagnose reception problems before.
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JB38: I should avoid writing aloud what I thinking. The TV tuner does better against the interference than the PVR and most of the time agrees that the RF is crap. However the PVR always produces a better quality of picture (when the system works) in the same way as switching on the 5.1 gives better sound.
It was raining when I finished the loop aerial & connected it up to a 9 portable TV placed to I can see it and main TV at the same time. Although the 9 reported steady green for signal quality (80%) and signal strength (80%) on the Mux, the picture was splattered with error pixels. So was it on the PVR, now only connected to TV only via SCART. So was it was on the main TV, as it was on a spare Digi box on AV input to 9. Four independent indoor aerials/tuners all said the RF was rubbish at that time.
The weather has not cleared so nothing works (error free) at the moment.
Watching the same program comparing two sources at the time I was bugged by a lack of synchronicity of the pixel error patterns until this morning, when I discovered why, the internal tuner of the 9 TV is the fastest, the TV sound echoes behind and the PVR video lags. The Digi box and TV seam in sync and the PVR sentence lags the Digi box. So Im getting time dilation.
Generally the interference was worse on the loop, then PVR, difficult to judge between main TV and Digi box because of the difference in screen size.
A retune of 9 TV on the loop discovered 3 of the 5 muxes. Mux signal quality/strength look reasonable across the board and are all Green. I think retuning is too error sensitive and lacks robustness.
I will wait for good weather, restore the tuning in 9 and go hunt for a good picture with loop position. When I get all Muxes found on a retune with the loop, I will consider connection to PVR.
What you be your suggested action plan?
I have noticed weird thing happening to the station number allocation by just switching aerials and I can see typical engineering folklore growing, Disconnect aerial, retune, reconnect and retune again. Does anyone have a handle on what might be going on? I dont think it is important to this problem, just curious
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Dholder: I would ask your Freeview box.
You should find somewhere in the menus an option to manual tune if you select this option it also displays signal quality and signal power. As you scroll through the frequencies or UHF channels these should react.
Signal power will give you a guide to the strength of the signal and if you get a reaction on signal quality, this shows it is detecting a digital TV Multiplexer (Mux) (where a group of TV stations are) and not just radio frequency background.
The fact you only see 3 radio would suggest your aerial/box is not picking up the BBC mux. So I would expect BBC1,2,3,4 are absent but I think ITV1 would be in your list of TV stations.
If you look at the Multiplexer TAB on this site, It clearly shows which TV stations share the same Mux. In digital TV the Mux has the frequency or UHF channel NOT the TV stations as in analogue TV.
Looking at your channel list, you should be able to work out what Mux or Muxes your NOT picking up. So, lots of digital TV channels have the same frequency, that the way it works (or not sometimes).
The scanning process appears to be a bag of bolts it is not very fault tolerant or robust. Im testing RF quality in a high signal strength area because my TV works brilliantly until it rains. DSO has forced me to find out what is where after a decade of being able to set up an indoor aerial in about ten minutes with a plonk, scan and a quick scroll, check for favourite channels method.
Assuming that you have an outdoor aerial as per Ofcom, DigitalUK et al think you should, see if its pointing in the same direction as most of the other one in the street. It might have been marginal before or have been struck by a low flying duck. If it agrees, then make sure it not wobbling in the wind that could give you problem too. Avoid scanning after rain or a period of wet weather just in case there is a water ingress problem on your aerial, water can cause havoc and might be your original problem.
If you are using an indoor aerial its more tricky, time to play the find the missing Mux game.
With the tuner on manual tune set the missing Mux frequency (UHF Channel) take a reading, probably signal quality is more useful to asses if you have a sweet spot or not. Try moving the aerial give it 30 second to settle down then take a reading, any better?
When you think youve found the best position or just got bored do another scan.
If you still stuck, then look up your transmitters Mux frequencies and take the measurements for each one always wait 30 seconds are they similar results for power and quality? If power is measuring at 100% Davids point above is a good one.
This is the zero cost DIY option of trying to find out what is going on. Why not borrow a digi box and repeat the trial, it might cope better or illuminate the Digi box and suggest more an aerial problem.
Having the numbers on the Muxes might be a good way to find a proper aerial specialist if he says Mux? Then move on.
There are other possible causes but retuning is not as bullet prove as it should be and I think it should be able to tell you your RF sucks or Okay Man at the end of a scan. Its a shame that you need to learn how to ask the question.
E&OE
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Gary: If youre looking at the signal strength although important, Signal Quality (or bit error rate) is the more important for reception. It is an indication how much work the digital error correction the tuner has to apply to the data stream. Less error correction or better quality is what you are after.
There would have to be very extensive work to support DSO with probably a lot of hardware going live for the first time on the 4th and 18th April 2012. It is described on the Arqiva website as a man turning a big lever from on to off in one hall of equipment moving to the hall next door and turning another big lever from off to on. Analogue went off on came the new Digital Mux(s). All I can say it must a moved very very slowly between the halls.
Frequent freezing would suggest that in some cases, the data is so badly damaged it gives up trying to produce a picture. The data is no longer correctable; it unrecoverable and we have gone way beyond an error pixel or two.
During these periods of freezing, you have a reception problem. Getting the best signal you can into aerial would a good start. You dont say how close to CP you are and my own reception problems are documented under the interference section.
Good Luck
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Tuesday 5 June 2012 12:58PM
NICK ADSL UK : Thanks for your posting. I might explain a bit of a reluctance to engage I have felt from certain quarters. There is far far more to a problem of this type than the just technical issues. I was clueless to the scale of DSO and the technical risks taken. Im very glad Im not involved with any of the discussions and events that led up to DSO; however as an ex- European Technical Support engineer would love a bash at being part of the solution.
For a decade Freeview sometime took 30 minutes to set up and find a sweet spot for the indoor aerial, then it that was it, stable as a rock until I bought the next bit of AV kit and wanted to move stuff around.