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After the last set of frequency changes a couple of months back, I’ve been getting lots of failed recordings on the HD channels (Beacon Hill transmitter, South Devon). I’m getting good signal strength, and excellent S/N ratio (62.8 dBuV and 36.25dB respectively).
The TV (Panasonic) has no issues with the HD channels.
In an attempt to fix the problem – and clutching at straws – I’ve done away with the loop-through feed to the TV, and used a cable splitter instead (4dB loss to each device). I’ve also re-instated the low-power stand-by, as I no longer need the loop-through.
This seems to have improved the failed recordings issue somewhat, but now, every time I switch the Humax on, it reboots!
I’ve tried disconnecting it from the mains for an hour to make sure it was thoroughly “cold”, and then turned it back on, but it hasn’t helped. Switching on from standby causes a reboot, which is frustratingly time consuming!
Any ideas, anyone?
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Pete
pchristy – 40 minutes ago »
After the last set of frequency changes a couple of months back, I’ve been getting lots of failed recordings on the HD channels (Beacon Hill transmitter, South Devon). I’m getting good signal strength, and excellent S/N ratio (62.8 dBuV and 36.25dB respectively).
Please could you quote the values as reported by the Humax when tuned to an HD channel?
If you are referring to the signal strength and quality, they are 95% and 100% respectively.
A lot of other people in the area have been reporting similar problems, so it may be a fault at the transmission end, but so far there is no explanation from the service provider, and it seems not all sets are affected. Prior to the frequency change, the HD channels were rock solid.
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Pete
pchristy – 10 hours ago »
If you are referring to the signal strength and quality, they are 95% and 100% respectively.
In my experience a signal strength of 95% may be too high for the Humax tuners. You might consider adding a variable attenuator to the aerial cabling and reducing the reported signal strength to say 80% and see if that helps.
We have a distribution amp in the attic with variable gain. I’ve tried it at both minimum and maximum, and it makes no difference. I can’t remember what the reported signal strength was at minimum, but I *think* it was around 80%.
It may be a stray reflection from something moving along the hilltop between us and the transmitter. There is a main road up there, and once or twice I’ve observed the received signal strength drop to zero for a moment. But it doesn’t seem to affect the SD channels!
And it still reboots every time I bring it out of standby – unless its already recording! Weird!
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Pete
Why not go back to using the loop-through setting to stop the reboots? At least as a temporary measure.
You say that recordings on HD channels are failing. If I understand it some of the HD channels have closed down (see https://www.freeview.co.uk/tvchanges/beacon-hill ). You don’t say what type of failed recordings you are getting. Nothing recording? Recording failed – lack of signal? Unable to track? Perhaps you could clarify.
Yes, I might go back to activating the loop through, though having the low-power standby used to work OK. I only went to the loop through when we moved here at first because we had a very poor signal initially. I had a new aerial and distribution amp fitted, and that cured the weak signal problem!
The failed recordings are mostly there, but get flagged up because there are “glitches” in them. Sometimes its just a brief burst of digital noise, but some times several seconds are missing. Very annoying when its a critical piece of dialogue or somesuch.
I’ve never seen it on “live” tv. Its only on recordings, which implies something is upsetting the Humax that the TV ignores!
Somewhere I’ve got a TVI filter. I’m not sure where it is since we moved house a couple of years back, but I won’t have thrown it out. If I can find it, I’ll try fitting that in the feed to the Humax.
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Pete
My one has been comimg on in maintenance mode itself. I select option 1 and it goes to previous software. Software just now is 3.6.62 which is older and should be 3.6.86. Done it 3 times sofar.
Well, it looks like I might have cracked the failed recording issue. I found the TVI filter and fitted it into the feed to the Humax. I also reduced the gain on the distribution amp to minimum, though I have tried this previously without success.
Last night it recorded two programs in high definition without issue! This is the first time its managed this since the channel change-over.
Its too early to say if this is a permanent fix, but its certainly looking hopeful.
I’ve activated the loop through again – or rather turned off the low power standby – which has stopped it rebooting on power up. But I feel that this is merely by-passing the problem rather than fixing it.
It will do for the moment, anyway. And I don’t suppose we will see anymore firmware updates…..
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Pete
I’ve had problems with either the COM7 or COM8 mux (I forget which one, it has forces tv on it). Often recordings are flagged as failed and there are one or two “glitches” in them. In fact, these are 1-2 second drop outs and, in my case, are visible when watching live (You might not notice them as the picture just stops and sometimes the sound continues). I put a filter in the aerial lead and the problem goes away.
We lost com7 and com8 when the frequencies changed. Funnily enough, I never had any problems with them, despite them being the lowest powered multiplexes!
It looks as if the Humax has a tuner that isn’t very good at rejecting spurious signals, as the TV never shows any issues.
Many years ago, we had a Philips (analogue) TV that was useless at interference rejection! It would pick up anything, on any frequency and lose the TV signal. Amateur radio, CB, model control transmitters – almost anything would knock it out! We replaced it with a Sony and that solved the problem completely!
The Humax isn’t as bad as the Philips, but it looks as if it is more susceptible to this kind of interference than it should be….
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Pete
pchristy – 1 hour ago »
We lost com7 and com8 when the frequencies changed. Funnily enough, I never had any problems with them, despite them being the lowest powered multiplexes!
It looks as if the Humax has a tuner that isn’t very good at rejecting spurious signals, as the TV never shows any issues.
Many years ago, we had a Philips (analogue) TV that was useless at interference rejection! It would pick up anything, on any frequency and lose the TV signal. Amateur radio, CB, model control transmitters – almost anything would knock it out! We replaced it with a Sony and that solved the problem completely!
The Humax isn’t as bad as the Philips, but it looks as if it is more susceptible to this kind of interference than it should be….
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Pete
Normally a result of the boxes very sensitive tuner. COM 7 and CM8 are being transferred to a single frequency network, As adjacent transmitters switch to the same frequencies the box has problems with being able to reject the unwanted other transmitters. Depending on where you are simply attenuating the signal may resolve the issue using a TV attenuator..
Not a box issue rather a issue with your location and the sensitivity of the tuners in your other kit. A new aerial and and new alignment might help.
Well we do live in a “difficult” location. We can’t get satellite as we live close to a wooded hill, and the satellite is below the tree line! In the other direction is Beacon Hill, and although its not very far away, it is obscured by another hill.
We had a new aerial installed shortly after we moved in, along with a distribution amplifier that incorporates a 4G filter. Initially we used to get drop-outs whenever it had been raining and a car went up the road! So we swung the aerial round to look at Stockland Hill. Then we got drop-outs whenever the steam train passed, depending on the state of the tide!
At this point I got fed up and re-aligned the aerial myself! I worked, briefly, as an engineer at a TV transmitter many years ago. Admittedly it was a 405-line B&W transmitter, but the laws of propagation haven’t changed much in the intervening years!
My re-alignment got us a perfect signal on every channel, except the BBC SD channels. This didn’t bother me as we had them in HD. The problem has only occurred since the frequency change. We now get everything with a very good signal strength and S/N ratio, except the HD channels dropping out for no apparent reason.
The fact that the TVI filter seems to have solved the problem leads me to the conclusion that there is an intermittent RF source somewhere along the path to the transmitter that is upsetting the Humax on a specific channel (HD). It could be CB, a taxi, police, ambulance, any number of things.
I do have a spectrum analyzer, but not the time to spend sitting staring at it for hours looking for the source of the problem. The filter seems to have done the job, so I’m happy for the moment.
I did consider buying a newer Humax, but the reports on the current line-up are not encouraging, with tales of clunky interfaces and other problems. Best stick to the devil I know! 😉
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Pete
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