Question BT Youview: Failed to Record problems

smallieboy

Active Member
I have a BT Humax DTRT4000 which is coming up to 2 years old. In the past couple of weeks it has failed to record at least 10 programmes. I checked the BT forum to see if others have had similar problems but they mostly seem to be Series Link related. In my case, they've been mostly films across a variety of channels including BBC1, E4, Film4 and, I think, one of the Sony channels.

High barometric pressure often causes signal loss and I thought that may have been the cause of the problem but even with low pressure I've been getting the same problem.

I did a factory reset on the box a few days ago and set it to record 'Strike' via Series Link and a film, 'The Accountant' - both on BBC 1. 'Strike' recorded OK; the film however, didn't.

I've seen on other forums that people have had similar problems while recording when the box is in smart standby but it would definitely have been on when the recording of The Accountant started. When I start a recording and manually put the box in standby it continues to record.

Over the past week I've tried recording a few films late at night and they have all failed which does lead me to suspect a standby problem.

Has anyone experienced similar issues or does anyone have any suggestions (other than contact BT which is my next step)
 

Rodders53

Distinguished Member
This is not something that BT can particularly help with as it is a Humax box issue and/or reception issue. BT boxes are just rebadged Humax running the YouView soft/firmware that their YV retail boxes run.

Location? (approx we don't need your exact address). To identify the transmitter(s) and reception predictions via the Freeview website.

What does the YV box report on the affected TV channels is signal strength/quality? (Ideally check and report numbers for all received multiplex frequencies).

Ideally you need to be specific with missed recordings TV channels times and dates as that can pinpoint a multiplex or two and a frequency-related issue.

Broadcasters do make mistakes and not all use Accurate Recording properly all the time, some not at all. BBC, however, is generally very good and reliable. (HD or SD recordings on the two you mention above?)

A regular problem used to be with cross-border reception of two transmitters and incorrect auto tuning giving rise to problems. Possibly solved with HD, DVB-T2 boxes like yours; or not?

Do you leave the box on/in standby all the time. Have you disable the power saving in standby as an experiment to see if that is a factor?

A 'default settings' aka 'factory reset' is often suggested when things play up. BUT that will start an auto tune and may still store two transmitters. It also needs the schedule of recordings noted down to be re-input after the tuning. It shouldn't delete any recordings on the HDD - iirc YV boxes ask if you want to do that??
 

smallieboy

Active Member
Rodders, thanks for your response.

The reason it's potentially a BT issue is that the box is supplied by them on a service contract and, if that service isn't being provided fully, it's up to them to sort out - i.e., if it's a faulty box, they have to replace it or they're in breach of contract.

Anyway, that aside, I have some answers to your questions:

I'm in south Dorset on (I think) the Rowridge (IoW) transmitter and am using a VP roof aerial. When I tested it today, the signal strength on BBC1 - which is where I've been losing most recordings - is steady at 94% and quality is 100%. On Film 4 it's the same. However, I don't think it's anything to do with that - why would it record one thing on BBC1 at 9pm but not something else, also on BBC1 at 10.30 pm? Does x-channel interference only happen late at night?

I noticed today that Invictus was only partially recorded last Saturday night, stopping 3 minutes from the end. If I recall, I was watching something on Prime at the time.

The box goes into smart standby after 3 hours of being idle; however, I have no idea what 'idle' means - if it's recording how can it be 'idle'? I've now taken it out of any standby mode and will try recording something but frankly, if that is the cause then the box has developed a fault; in the past I've recorded OU programmes in the middle of the night without issue. This is something that has started in the past 1 - 2 months - I note there's been an update to that box on 4 August (although I think this problem started before then).
 

Rodders53

Distinguished Member
Broadcaster errors happen. Unless you find someone else who has recorded the same programmes without issue it could be a transmission problem? You do need to specify if HD or SD recordings are being made (different frequencies).

BBC are better than most though!

However:
You'd be one of the very rare viewers that have installed an aerial for Rowridge vertically polarised. Vp does, however, reduce the chances of continental transmitter interference cf horizontal so it should be better.

Postcode of nearby shop, pub, school church would help identify alternative transmitters. As would a list of all the frequencies you have tuned in (together with signal/quality levels for each).

94% signal on a Humax means a very strong signal and could mean overload happening? That gives reception problems very similar to inadequate signal, with breakup and suchlike. 70-80% is the ideal for them, apparently; and, allegedly, can be a bit 'fussy' about the level. Reduce the gain on any variable aerial amplifiers in your aerial system to reduce it? or fit a cheap attenuator to try for a time?
NB measure all received multiplexes for signal and quality to assess if they are all high level and ought to be reduced (or not).

Vp would also likely mean you can't receive COM7 on ch 55 as it's lower power and Hp only. Therefore you'd not have BBC NEWS, BBC FOUR and CBeebies in HD, nor QVC HD etc.,. that are on that temporary multiplex.
 

smallieboy

Active Member
Rodders, apologies for the tardy response but BT have given me a new box. However, I've recently had a couple of missed recordings again so have reviewed your 2nd reply .....

Whilst I didn't have the aerial installed - it was already there when I moved in - your comments about COM7 confirms to me that it is VP; I don't have any of the COM7 channels (not that it bothers me).

The postcode for the nearby post office is DT1 2LN. As far as I can tell from speaking to neighbours and friends, we're all on the Rowridge transmitter group. If I check frequencies on my TV (I can't see a way of doing it except by individual channels on the STB) I have the following

Channel Strength Quality
21 (PSB3) 66% 75%
22 (COM5) 82% 0%
24 (PSB1) 80% 87%
27 (PSB2) 78% 40%
I don't know the relevance of this but on Ch21 and 24 it says Transmitter: South but on the other two it says 'cannot read NIT' - maybe due to low signal quality?

I seem to be getting more channels through the STB - Ch25 (COM4) although it does break up quite a lot (Strength: 82-86%/Quality: 100%) and 28 (COM6) - S: 95/Q:100. Even on 22 & 27 where the quality is low (or 0) on the TV I still seem to get good reception on the STB.

I have got an 'adjustable' attenuator so was considering trying it out. Should I be aiming to bring the strength down to 70-80%? Presumably, doing so will affect all channels equally?

Oh, they're all SD recordings.

Thanks for any help/advice.
 

Rodders53

Distinguished Member
First:
Measure all 6 muxes on the PVR 'as is'. You've only specified two out of the 6 in the previous posts.

Then install the attenuator and aim for (say) around 70-75% on all 6 (they will vary a bit) down from what you have currently. {NB the BT community forum advises 70-80% providing the quality is 100% on all.}
Note the new readings and the 'setting' of the attenuator to aid replication if you make later adjustments.

Then: re-measure the signals on the TV on all 6. Hopefully they may have improved in quality level readings if not signal level.

You can repeat with more attenuation (lower signal) or less (higher signal) if you want to gauge the effect it has on both the PVR and the TV.


PO/shop Postcode: ROWridge Vp is good predictions. Hp is worse but not that bad in fact. However Vp is better so the correct one to use!
Wolfbane suggests 46 dBuV/m Field strength at 10 metres above the ground. It's not 'line of sight' but 'diffracted' reception off a hill or ridge between the PO location and the transmitter aerials; this can mean precise aerial position can be critical to get all frequencies received equally.

Now TVs/PVRs require between 45 and 65 dBuV input ideally. Too little = breakup. Too much = overload and breakup.
So let's do the calculation:
46 dB + (high gain aerial, say) 10 dB - (downlead cable and termination losses, say) 4 dB = 52 dB which is a little on the low side of median ideal level.
That suggests to me that there must be an amplifier involved. Either a masthead (external box with a power supply indoors) or an indoor amplifier (perhaps an amplified splitter aka distribution amplifier if multiple sets are fed from the one aerial).

A low gain amplifier is typically 10 dB: 52+10 =62 dB = good level no reason for your issues.

A higher gain amplifier may be 20 to 26 dB + 52 = 72 to 78 dB and could perhaps cause overload? Especially if the aerial has more than my estimated 10 dB gain, although unlikely - see ATV aerial gain tests : all the gain curves - A.T.V. Poles, Brackets, Clamps & Aerials

You haven't (as far as I recall) mentioned amplifiers? If you have one try to find its make and model. Some have variable gain controls that could reduce the output level without use of the attenuator?
 

smallieboy

Active Member
Hi
Thanks again for your response.

As I mentioned, this was all installed by the previous owners of the house but according to the receipt they left, I have a 18A aerial and Wolsey WFAV425 masthead variable amplifier which, I assume is in the loft - it was installed in June 2013. The specs for the amp say its 25dB gain so if it was operating at full power, it may be overloading.

I'm not sure how relevant this is but they had Sky in their lounge as well so my guess is that their aerial connections were direct to TV's in two of the bedrooms, so any settings on the amp may not take PVR's into consideration?

While reducing the power on the amp may be the logical way to try and fix this the attenuator may be easier - unless there's a way of measuring the output at the amp (otherwise there's going to be a lot of running up and down ladders/stairs :()
 

Rodders53

Distinguished Member
Antenna Yagi 18: +9 dB at ch 21 to +13 dB at ch 30 to 0 at ch 45 (so no COM7 possible even Hp). ATV aerial gain tests : all the gain curves - A.T.V. Poles, Brackets, Clamps & Aerials

Wolsey amp in loft: 10 dB gain at minimum setting to 25 dB at max, on a 1 way model but would have passive splitters after. http://www.farnell.com/datasheets/2823541.pdf
Or the 4-way version 4 Way Masthead Amplifier & Power Supply Wolsey WFAV 425 Variable Gain Up To 25db for sale has 12 to 25 dB gain variation.

From my earlier calcs (post 6) 10-12 dB gain should be in the ideal range - even with an extra dB or two of aerial input:

1) Take all mux signal readings on both PVR and TV in the 'as is state'.
2) Go up to loft: Set gain to minimum and
3) Repeat the full set of measurements.

If levels are a bit low, then set gain approx halfway and repeat measurements.

Likely minimum or up to halfway will be in the correct range?

NB Above post has been edited due to 1-way vs 4-way amp differences. Likely the installed one is 4-way... as passive split is -8 dB for 4-way so less likely to cause overload. Even so the basic reduce down to minimum I'd still recommend.
 
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smallieboy

Active Member
Thanks Rodders - I'm glad there's someone out there who understands all this. I'll have a go at this at the weekend.

FWIW I think the 4 in WFAV425 indicates the 4-way element; the Armstrong site has the LTE WFAV 25 as a 1-way and the 225 as a 2-way.
 

smallieboy

Active Member
Rodders, thank you for your patience and help with this.

OK. Firstly, the amp is a 4-way.

After a bit of trial and error I've set the gain to about 25% and now seem to have a steady picture on all channels and have done a few test recordings since the weekend and am pleased to say that all is working satisfactorily now.

Thanks again.
 

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