Signals: September 23rd or thereabouts

Norrette

New Member
Call me over suspicous but I wonder if something happened to Freeview signals on or around this weekend. My sister's Foxsat gave up the ghost and refused to reformat or check disk or anything (a bit embarrasing as I recommended Humax to her) - she's since had it replaced.

My own T2 started to play up at the same time (I had been away that weekend) recordings started pixellating, first of all on the BBC News Channel. Then it started on other channels. I am in the process of backing everything off, but as I am doing this the new recordings are getting progressively worse - with jumps and skips in the recording. (the old pre-September recordings are absolutely fine by the way)

I've tried other remedies, such as retuning, or reconfiguring to keep HDMI cables clear of the box - I went to scart only at one point, but it is still happening. I've still got some more backing up to do before I experiment.

I had presumed it was a disk problem - or even a disk write head problem. But very recent radio programs I've recorded are absolutly perfect.

Edit: Rewind replay is perfect as well.

Any ideas?

Norrette
NW London UB postcode
 

Black Hole

May contain traces of nut
It's hard to see how there could be any connection between Freeview (terrestrial TV) signal disturbances and a Foxsat (satellite TV receiver).

Your symptoms could be caused by disk problems. This can impact even live TV, because there is buffering to support live pause etc. If a disk write takes several retries to complete successfully, it is interrupting the rest of the system in the process.

You need to back-up to preserve recordings in case of disk failure, but note the restrictions caused by encryption - see Things Every... (click) section 5. You do not need to back-up in order to attempt rescue of the file system, which you should be doing sooner rather than later.

Quick Guide to Disk Recovery (click)
 
OP
N

Norrette

New Member
Thanks Black Hole. I've got about 780 gB free on my 1TB so only about 12-16 hours to back off. Encryption not a problem as I've streamed those ones off to DVD recorder. I might hurry the process by backing off to portable hard drive. (And switch off my auto recordings until sorted) Might start looking for a new piece of kit. (Ironically I never used more than 50% of the drive)

I will try the custom firmware too. If only to familiarise myself with it for future use.
 

Black Hole

May contain traces of nut
Once you have discovered the options available with CF, I doubt you will want another piece of kit - we don't!

Encryption not a problem as I've streamed those ones off to DVD recorder.
Oh lovely, 625-line analogue TV. How quaint! You're making life hard for yourself unnecessarily - check out my link.
 
OP
N

Norrette

New Member
I know, I know... but it's rare content rather than form that I wanted to keep...if I wanted better quality then I'd buy the blue ray DVD (when available) Looks like the T2 has lasted long enough for me to avoid the 4000T by some of the reviews I've just read. I will miss the T2 if the disk is truly borked. I don't have enough time to fiddle with installing a new disk. I do still have the previous model in a cupboard somewhere, I'm not bothered with HD - the TV provides that.
 

fenlander

Active Member
This is probably unrelated to your specific problem, but at the same time it's something that may be worth sharing.

I had symptoms very similar to yours: pixelating / no signal on various channels, especially BBC News and other HD channels but also affecting SD channels in bad weather. Worse in the morning, better in the evening. It affected all my equipment, so clearly it was not down to the Humax. It began the morning after the last major retune (August?). Previously I had had no such issues, so I suspected that something had happened to the Freeview signal. However, nobody else in the vicinity seemed to be having similar problems, so Freeview retune nothwithstanding, I turned my suspicions to my aerial.

Before calling in an expert, I checked out the cabling and noticed the old aerial amplifier in the loft. This was installed many years ago when Cambridge was a fringe reception area in the Sandy Heath catchment. Since the digital conversion, I am told that Sandy Heath has become one of the most powerful transmitters in the country, so I saw no reason not to remove the amplifier and replace it with a passive 3-way splitter.

Problem solved! The signal quality readouts instantly went back to 100%. No more pixelation; flawless reception on all channels.

Exactly why the amplifier became a fail point just at that particular moment, I do not know. Clearly the amp was causing serious degradation of the signal and this became critical at the time of the retune. Perhaps someone with more expertise than myself might have an explanation, but the moral, I guess, is to beware of old bits of kit lurking in inaccessible places.
 

Trev

The Dumb One
Exactly why the amplifier became a fail point just at that particular moment,
It likely caused signal overloading in the tuner(s) input RF circuitry which destroys the quality, and on some sets and makes the sig level read zero even though there is plenty (too much) signal present.
I suspect that the OP might benefit from trying an attenuator in the aerial circuitry or removing any amplifier that he has installed (as per fenlander found). DTV needs much less signal than the old analogue TV and too much is a show stopper.
 

Black Hole

May contain traces of nut
I don't think that's it at all. If the signal is strong, the transition from OK to cliff-edge is very sharp and exhibits a great deal worse than a bit of pixellation. The signal would be more likely too weak than too strong, if it's a signal problem at all.

Easy enough to check: Menu >> Settings >> System >> Signal Detection, monitor each mux for half a minute or so and check whether the quality drops below 100% at any point. If it does, is the strength figure high (100%) or low (<50%)? (Note: quality can remain at 100% even with strengths much lower than 50%.)
 

fenlander

Active Member
I suppose it could be that fenlander's 'amp' was working more as an attenuator rather than an amp. I wonder if it was actually powered or a PSU failure.
It appeared to be working inasmuch as the power light was on. I can understand an equipment failure but the coincidence of it happening coincidentally with the retune after years of trouble-free operation puzzles me.
 

fenlander

Active Member
I can't be sure - it was a couple of months ago. The spook community knows that there's no such thing as coincidence, singly or in multiples.
 
OP
N

Norrette

New Member
It's a five-minute operation. It takes longer to get the unit out of the AV stack than actually change the disk! It definitely takes longer to choose and buy a new PVR than change the disk.

https://hummy.tv/forum/threads/hdr-fox-hardware-commissioning-disassembly-repair.5728/#post-109121

You be surprised how quickly I can 'shop'. On the other hand - with my useless hands I'd need a couple of days to do the disassembly (with contingency time).

All now backed-off - Hard disk check gave error 8 - no surprise there.

Am about to reformat HDD but want to source a 5000T ready to go if the whole thing is unusable. I note that John Lewis are selling the 500GB version with a two year guarantee. But they are not selling the 1/2Tb versions at all. I wonder if there's an insider on here who knows if these higher density disks are the exact same as what's been put in the T2? And therefore with the same shelf life?

Thanks for all your help folks
 
OP
N

Norrette

New Member
I don't think that's it at all. If the signal is strong, the transition from OK to cliff-edge is very sharp and exhibits a great deal worse than a bit of pixellation. The signal would be more likely too weak than too strong, if it's a signal problem at all.

Easy enough to check: Menu >> Settings >> System >> Signal Detection, monitor each mux for half a minute or so and check whether the quality drops below 100% at any point. If it does, is the strength figure high (100%) or low (<50%)? (Note: quality can remain at 100% even with strengths much lower than 50%.)

Just for information mine is : strength wavering 76-78 (ch22/23) but up to 80 on a couple of other channels. All with 100% quality all the time. I live in a frost pocket and therefore slightly limited field of view.
 
OP
N

Norrette

New Member
Update. I have just discovered a recording fail on my sparkling new FVP 5000T, same pixellation, same jumping, same issues. On that piece of kit the signal strength is showing 100% (am going to get an attenuator and I'll use a cheap indoor aerial until then. ) I reckon something DID happen to signal strengths this summer - perhaps PVR manufacturers need to think about inbuilt attenuation kicking in when required - to prevent burn out of the tuner/s? They should warn people during set up to check that it's not too high.
 

Black Hole

May contain traces of nut
The tuners won't "burn out", but that doesn't stop them saturating.

Questions of signal level are the bailiwick of the aerial installation, and not something the receiver supplier has any control over. The ordinary person would simply call in an expert; DIYers should have the relevant expertise (or be prepared to learn by trial and error). There's no way the vast majority of the consumer market would be able to use such a warning.

What the ordinary person would struggle with is the concept that a signal can be too strong, and that a signal strength indication of 100% actually means "anything over 99% of whatever arbitrary signal voltage was chosen to represent 100%". An educated guess suggests that the signal strength reading is a measure of the control voltage used in the gain control feedback loop, and 100% is the point at which the gain cannot be reduced any further. Thus there is already built-in attenuation, but it will always reach its limit sooner or later. The existing front end is adequate for the vast majority of situations, and any further complication would add cost while only benefiting an insignificant minority.

The most important stat is the quality, which should be 100% at all times. If it isn't, the signal strength figure tells you whether you have too little signal, or too much.
 
OP
N

Norrette

New Member
Thanks Black Hole. Boy am I confused.com. According to http://www.aerialsandtv.com Crystal palace is the most powerful trasnmitter in the country. But as I'm 29km away, no line of sight, in a dip, I'm baffled at such a strong signal. And again, why no problems with my telly. Have just made all the notes for a manual retune - cutting out Hemel Hemstead which is only 20km away but in the almost opposite direction. The portable aerial is missing loads of channels, so that won't do. Ho hum

ps quality 100% without fail
 
Top