Well, it's a long shot, but someone might have an off-the-wall idea that will help me solve a very odd problem with my Panasonic HDD TV recorder. I've googled plenty but not come up with a solution.
The Panasonic DMR-EX85 is an HDD recorder, with an integrated digital tuner and as an aside a DVD recorder/player. It was bought in the UK back in around 2007-8, after a lot of research, and was highly regarded at the time for the quality of it's recording. When we moved to Austria in 2009 it came with us.
Anyway, it's had a couple of problems, the solutions to which were found by googling. But the one that no-one can solve is the loss of sound on just one channel. It tunes in to all the Austrian terrestrial digital channels perfectly, but on just one, always the same one (ORF1), the sound disappears regularly. I can get it back by retuning the box, but it's a bit of a pain as it can be every couple of days. The problem disappeared for a couple of weeks when it had a repair last year, but it came back. At that time, the engineer upgraded the firmware which I thought might have solved it, but we're back to square one.
It connects to the TV via HDMI, but it's not a cable problem as there is a direct phono output to the amp, and neither have the sound when it fails.
Any ideas gratefully received!
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Haven't a clue, but straw clutching - Is the signal strength of ORF1 lower than the other channels, causing the audio to drop out?
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Must be related to the multiplex on which this channel is carried. Maybe it's using an encoding that sometimes upsets the Panasonic box and it no longer has sound.
I take it when there is no sound on this particular channel, there is sound if you switch to another station?
One thought, is there another broadcast frequency also carrying this channel you could try? Depends on your area. But for example where I live I pick up the digital TV channels from more than one mast. Maybe you're picking up a signal from outside the area and another stronger signal is available?
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From your description of the sound loss on one MPX it is a problem with the received signal not the Panny box.
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I would guess its the way DVB-T is implemented in Austria. Your box is DVBT-2 ready, and Austria isn't. (I think)
Either way, its caused by the way its transmitted and received probably noting you can do.
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It is unlikely to be your box, it is probably the signal you are receiving.
Do you receive any other channels from that same Multiplex? Do you know if they are the same format?
Is it a channel which has local variations, and if so are you tuned into the most appropriate one for you? (Which may not be the one with the most obvious LCN (Logical Channel Number)).
Is your aerial flexing or moving at all? Is it next to a tree or similar?
Are you using a secondary audio program or the main feed?
Looking at signal strengths (say if you don't know how to), is that channel particularly lower or more variable than one of the others?
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Too much information, and some of it meaningless to me :-( Tomorrow, I will take a good solid look at some of the ideas and try to make sense of it all. I can say that we get variations on ORF2, picking up two distinct area variations (Salzburg & Upper Austria), and the sound is always fine on those even when the offending channel is mute. Aerial is not next to a tree and is simply quite open on the roof in full view of the only local transmitting aerial.
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To answer the questions I think you are asking, there are 3 other stations on the same DVB channel (32), which I think is what you mean by multiplex? The signal strength is more stable than the quality, hovering between 5 and 7 out of 10. The quality is very variable, between 3 and 7 out of 10 - but all 4 channels seem to be showing extremely similar characteristics. The weather today is a bit unusual, with wind, snow & low cloud, so I can't compare what happens on a regular basis.
There are two versions of ORF2 on the DVB channel, a third unrelated, and the one I'm having trouble with. There are no regional variations of ORF1. I'm not aware of the aerial flexing.
I'm not aware of using a "secondary audio program", I just tune the channels in!
I have previously, and today, had a good rummage round the menus and there is nothing that I believe would have an effect.
From what others have said, I my understanding is that basically I'm stuffed because it's the signal.
Just a further thought - the aerial isn't our installation, it was here when we bought the house 4 years ago. There is certainly a signal distribution box in the roof space, because the signal was originally split to a number of aerial points throughout the house. I have no idea whether there is be an amplifier involved. Is there a chance that it would help by connecting the feed from the aerial directly to the feed for the box? The total cable run is probably around 10 metres. For our main TV we rely on satellite, which has good HD reception, we only use the DVB-T for recording - unfortunately, most of what we want to record at the moment is on the offending programme!
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You may well have a wiring problem - typically duff connection wiring/contacts.
Connecting the aerial to the box directly would absolutely help. Try it, if the problem goes away then you need to start chasing through connections and splitters - checking at all are good quality and that no one feed is being unreasonably split.
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If you don't need the distribution / amplifier box then a direct link is always better. The number of connections (plugs) always attenuates the signal.
I doubt its signal tho, in the old analogue days when there was a frequency offset for audio then yes, these days any digital signal issue will show as freezing / blocking with the video first.
I still think its a Austrian compatibility issue with your Uk supplied box.
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>> any digital signal issue will show as freezing / blocking with the video first.
Often, yes. But not always. And Zero is correct about a potential compatibility issue, although I'm not aware of any. However, depending on what you are watching, it is possible for audio to lose the plot first.
Nonetheless, we both agree that you should put a direct link in first and see what you get. Take note of signal strength and quality, not just the final result on your screen/speakers.
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Presumably your TV is a modern (isn) one with digital tuner? Therefore what happens when watching the problem channels on the TV rather than on/via the STB? If the TV has the same problem then maybe a signal issue. If it's fine then maybe a STB compatibility issue.
IF your TV is a Panasonic.... and might have the same tuner then try a different make of TV too.
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TV is a Samsung with DVB-C, DVB-T and DVB-S tuners. I tried the DVB-T version on the TV earlier today and everything was fine, although the Panasonic was OK then as well! Will try the TV when the Panasonic has problems. As I said, we don't rely on the terrestrial signal for the TV anyway, as we can only get HD on satellite, so that's what we normally use.
Thanks for all the suggestions, I'll try the direct aerial to tuner feed when I have a minute.
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So why do you usually watch via satellite? Is it because the reception is poor :-) I guess you're watching channels only available via satellite?
Sounds like the TV might support more DVB-x formats than the TV? Can you not just get a satellite receiver/recorder and have exactly the same channels to watch/record that you normally watch anyway?
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>> So why do you usually watch via satellite? Is it because the reception is poor
>> :-) I guess you're watching channels only available via satellite?
>>
No, nothing to do with the transmission quality, we watch by satellite because the HD transmissions for the state-run channels (ORF) are only available by satellite, and require a card to receive them. Until 18 months ago we used the terrestrial digital for all our TV viewing, and had no problems with sound loss - and the TV came from the UK.
>> Sounds like the TV might support more DVB-x formats than the TV? Can you not
>> just get a satellite receiver/recorder and have exactly the same channels to watch/record that you
>> normally watch anyway?
>>
Yes, the TV supports cable, terrestrial and satellite. However, I seem to remember reading somewhere that you can't just split a signal from one LNB, as you could with a terrestrial aerial, and I'm assuming that's because it's an active device and has power running to it? I have a satellite receiver with an LNB-in and LNB-out, so as an experiment I connected the satellite feed to the LNB-in, and the LNB-out to the TV. While the receiver was switched off, the TV was fine, good picture in full HD. As soon as I switched the receiver on, the TV lost it's signal because the receiver was "using" the dish, for want of a better word. I'm assuming this is normal of course, and that my perception of how this all works is correct :-)
Therefore, I believe I need a second feed from the satellite dish if I want to run two devices (which technically I could do, as it has 2 LNBs, one of which we don't use). Without this, as I understand it I can only record the channel I'm watching, which is pointless, or, if I want to record, I can't actually watch anything via satellite on the TV.
Yes, I did look at satellite receiver/recorders last week, but it seems that solution only works if I have the second feed. It would have some benefits, as I could then record the HD channels by getting a recorder with a CI slot, and buying a CI Module and a second card.
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>>Therefore, I believe I need a second feed from the satellite dish if I want to run two devices (which technically I could do, as it has 2 LNBs, one of which we don't use). Without this, as I understand it I can only record the channel I'm watching, which is pointless, or, if I want to record, I can't actually watch anything via satellite on the TV. <<<
You need to make sure whether it is
2 LNBs with an offset 'angle' designed for receiving 2 different satellites (in which case you cannot use the second connection to do what you wish)
1 LNB withe 2 independent ('twin') outputs which can be used to feed 2 independent receivers.
There are other variants (with 2 connectors on the LNB) but that will probably just confuse the issue further.
Just one long shot thought for the original problem, if the tx is visible is the tuner input being overloaded. Have you tried working with just an an indoor wire aerial?
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>> Just one long shot thought for the original problem, if the tx is visible is
>> the tuner input being overloaded. Have you tried working with just an an indoor wire
>> aerial?
>>
I reported the signal strength & quality yesterday morning at 08:44, it's not consistently high, it's comparatively low.
Ah, I'm pretty sure it's the one LNB with independent outputs, because we did briefly use it for that.
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>>>Ah, I'm pretty sure it's the one LNB with independent outputs, <<<
You said earlier that it was 2 LNBs :)
Signal strength monitors on inbuilt tuners (partic sat rxs) can be very mislaeading, does it show signal quality as well and is it for specific 'channels'?
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>> You said earlier that it was 2 LNBs :)
>>
Before you explained the difference, I wasn't aware that there was a difference between 2LNBs, and one LNB with two outlets, hence the confusion. You should have worked out by now that I'm a lay person where all this is concerned! I'm a "plug it in, tune it up, and off we go" type! :-)
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Sounds like the aerial may be an old one suited for the analog transmissions which might not be the best for dvb-t.
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Could you explain the difference between an analog and digital aerial? :-)
Last edited by: Uncle Albert on Mon 27 Jan 14 at 07:55
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>> Could you explain the difference between an analog and digital aerial? :-)
The former is tuned specifically to a specific and quite narrow frequency range or group of channels. The latter is known technically as 'wideband' and will receive all the channels used for TV albeit with lesser performance at the outer limits.
It'll either be a big yagi or these days a log periodic.
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>> Sounds like the aerial may be an old one suited for the analog transmissions which
>> might not be the best for dvb-t.
>>
That is a definite possibility, but other than the sound loss, we get an excellent picture, probably helped by the fact we can actually see the transmitting aerial.
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>>>Sounds like the aerial may be an old one suited for the analog transmissions which might not be the best for dvb-t.
Digital reception can need more thought about aerial types and sometimes give unpredictable results.
As said by others above usually a change to wideband type is required as a first step to digital. However many cheaper or standard wideband aerials have varying gain across the channels and this can show up with issues on just one channel group.
Furthermore many cheap/standard aerials are poor at rejecting unwanted signals from directions other than the transmitter you wish to receive... many will pull in unwanted interference signals from behind them in particular.
As long as you are in a medium to good reception area the very best aerial type to resolve these issues is a "Log" type. These have a very flat gain across the wide channel range and are excellent at rejecting unwanted interference signals from other directions... particularly from behind.
They are usually strongly made and do not catch the wind like conventional aerials. Example below...
www.wtw.co/Upload/Product/e2e680da-5a99-450e-8eb7-0610fa2c6eae.jpg
Since we moved to this house 2yrs ago we'd been using the existing digital approved (but cheap) wideband aerial in the loft. Reception was just OK but with dropouts sometimes due to weather. Then we noticed a whole group of Freeview channels were missing despite a signal strength of 80%-100% being shown for all other channels. Finally the purchase of a HD Humax box prompted aerial work as the HD channels were all missing.
We had the installer put a log type aerial on the chimney and all issues were resolved.
Similarly at our last house a Wickes wideband aerial that should have worked in theory gave unpredictable reception across the channel groups but everything was sorted with a log type.
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Thanks for the aerial suggestion Fenlander, I need to work out whether it's worth the expense and effort. As I mentioned in another post, I could run another sat cable from the existing dish (relatively cheap and easy), but then I need to buy a new satellite receiver/recorder. From a quick look last week, the box will be around €150 using an external HDD. I need to investigate further. The current aerial installation is also in a particularly inaccessible place in the middle of the roof, no an easy job for me to tackle!
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I don't think you've answered whether the TV using the aerial connection also suffers sound loss when the Panasonic DMR EX-85 does. If it was down to signal and the aerial then both would have problems with sound on that channel. If it's something to do with how that channel is being encoded and the TV is okay with it but the Panasonic PVR is not.
When I said the TV might support more DVB formats than the 'PVR' (typed TV before) I was still referring to terrestrial and not satellite broadcasts.
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>> I don't think you've answered whether the TV using the aerial connection also suffers sound
>> loss when the Panasonic DMR EX-85 does. If it was down to signal and the
>> aerial then both would have problems with sound on that channel. If it's something to
>> do with how that channel is being encoded and the TV is okay with it
>> but the Panasonic PVR is not.
>>
True, but I'll have to wait until I lose it again to find out. I mentioned at 22:13 yesterday that the sound was OK on bit the TV and the PVR at that point. I'm assuming it's not a problem, as the sound is regained when I retune the PVR, but I've not retuned the TV since I got it. But as I said, I'll check next time.
No idea what terrestrial DVB formats the TV supports but will check the manual later (if it's there, the TV has an inbuilt manual, and I might need to look online.
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What model TV is it?
One reason I suggest checking the channel on the TV (or another device) when the PVR goes wrong is it rules out the signal/aerial (probably). No point in buying a new aerial if it's a compatibility thing with the PVR.
One thing I am wondering is if it's a modulation related issue - the problem channel say 64QAM and the PVR not liking it. Just a thought.
Last edited by: rtj70 on Mon 27 Jan 14 at 16:42
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My thought on modulation should have been 256QAM is is part of the v2 of DVB-T (i.e. DVB-T2). But a quick search says Austria isn't one of the counties to adopt DVB-T2.... so probably forget that.
I wonder if there's a firmware update for the Panasonic box?
Last edited by: rtj70 on Mon 27 Jan 14 at 16:49
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>> I wonder if there's a firmware update for the Panasonic box?
>>
I had the latest one applied last year by an engineer who fixed one of the common problems with these boxes. It's at level 1.20.
And I lost the sound again on Tuesday evening. I checked on the TV's own DVB-T tuner and the sound was there, so clearly it's an issue with the Panasonic box, or the signal strength/quality that the Panny can't cope with. Incidentally, I forgot to mention that the TV (Samsung UE32D5720) shares the same terrestrial aerial - the aerial lead comes into the Panny, then out again and on to the TV.
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>> One thing I am wondering is if it's a modulation related issue - the problem
>> channel say 64QAM and the PVR not liking it. Just a thought.
>>
Can we have that in layman's terms please! ;-) How would I find that sort of info out??
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I don't claim to know how it works but basically the higher modulation rates means more compression of the video so less bandwidth is needed for a given quality. So you can either have better quality or more channels.... they go for the latter.
I was wondering if this channel was using a modulation that the Panasonic box does not like. I was thinking more of the 256-QAM which I then notice isn't being used in Austria (DVB-T2 rather than DVB-T).
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I wonder how the signal strength and quality compare between the TV and the PVR?
When I've had problems with an aerial on a TV USB stick on the Mac though, it usually results in the image breaking up (not getting the next info to update the display). Sound breaks up too. Not looked into how audio is transmitted on DVB-T to be honest but it must be interleaved with the video.
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Panasonic DMR EX-85 losing sound - Aretas
