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Author Topic: Why does my digital TV freeze?  (Read 24292 times)

Don_1

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Why does my digital TV freeze?
« on: 26/02/2009 09:20:42 »
Analogue reception on my TV is good. I tested the signal strength and found it to be maximum strength on BBC 1 & 2, ITV and Channel 4. But when I switch to digital TV, the signal freezes then jumps. I have been told that this is a result of my roof mounted aerial swaying in the wind. Is this correct?

Incidentally, (can you believe it, in a London suburb?) we do not get Channel 5 digital broadcasts here and won't get it until 2010.

wohenben

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Re: Why does my digital TV freeze?
« Reply #1 on: 27/02/2009 21:58:25 »
Sounds like the signal is just too weak.  If it's marginal, then aerial swaying might account for it falling below the threshold needed to decode a picture.  (Have you gone outside to see if it is actually swaying?) But most radio signals fluctuate anyway for various reasons.

No channel 5?  Some advantages in living where you do then.  ;D

FuzzyUK

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Re: Why does my digital TV freeze?
« Reply #2 on: 27/02/2009 23:50:15 »
Analogue reception on my TV is good. I tested the signal strength and found it to be maximum strength on BBC 1 & 2, ITV and Channel 4. But when I switch to digital TV, the signal freezes then jumps. I have been told that this is a result of my roof mounted aerial swaying in the wind. Is this correct?

Incidentally, (can you believe it, in a London suburb?) we do not get Channel 5 digital broadcasts here and won't get it until 2010.

Are you actually picking up the digital TV signal from the London transmitter or from some other area? You can only use your existing antenna for digital use in the London area. In almost all other areas you need to change your aerial for a broadband type.

Check the connection on the TV coaxial plug. The braid may have shorted to the inner if you have recently moved it.

neilep

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Re: Why does my digital TV freeze?
« Reply #3 on: 28/02/2009 02:34:58 »
I'm in North London and I get Channel 5 just fine on Freesat and analague...lucky me !!...nyahh nyahh !! *blows raspberry then runs away*

Heavy rain can cause problems ...has it been raining on your aerial ?

Karen W.

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Re: Why does my digital TV freeze?
« Reply #4 on: 28/02/2009 04:24:12 »
The digital freezes on mine also.. I am out of city limits ... but I do not know why it does this.. it freezes and then a handful of garbled square digital looking warble happens then it pops out of it and runs fine.. does it every now and then only lasts a second or two or three.. LOL

lyner

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Re: Why does my digital TV freeze?
« Reply #5 on: 28/02/2009 20:50:16 »
You are obviously 'marginal'. after switchover, you will get ten times the level of signal so you'll be fine. Patience, my dear.

Make it Lady

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Re: Why does my digital TV freeze?
« Reply #6 on: 28/02/2009 20:57:38 »
Take it out of the freezer!

RD

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Re: Why does my digital TV freeze?
« Reply #7 on: 28/02/2009 21:39:05 »
The digital freezes on mine also.. I am out of city limits ... but I do not know why it does this.. it freezes and then a handful of garbled square digital looking warble happens then it pops out of it and runs fine.. does it every now and then only lasts a second or two or three.. LOL

This type of momentary problem can be caused be electrical interference:
When I switch a particular desk lamp on, my digiTV/Radio box goes silent for a couple of seconds before it recovers (RFI).
 
« Last Edit: 28/02/2009 21:45:30 by RD »

FuzzyUK

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Re: Why does my digital TV freeze?
« Reply #8 on: 28/02/2009 22:05:28 »
I'm in North London and I get Channel 5 just fine on Freesat and analague...lucky me !!...nyahh nyahh !! *blows raspberry then runs away*

Heavy rain can cause problems ...has it been raining on your aerial ?


Freesat is not the same as Freeview.

Freesat signals are transmitted from a geostationary satellite and the transmissions are in the Gigahertz frequency range. And yes, signals may be susceptable to attenuation by rain if the dish is slightly off alignment or if there are any tree branches or other obstructions like overhead telephone wires in the way.

Freeview is a terrestial broadcast system which operates in the Ultra High Frequency (UHF) bands. The range is divided into three sub bands, group A, B, and C. For the London area your antenna would be group 'A' and your antenna should have a red plug identifying it as such on the end of the boom holding the aerial elements.
« Last Edit: 28/02/2009 22:13:34 by FuzzyUK »

FuzzyUK

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Re: Why does my digital TV freeze?
« Reply #9 on: 28/02/2009 22:18:03 »
The digital freezes on mine also.. I am out of city limits ... but I do not know why it does this.. it freezes and then a handful of garbled square digital looking warble happens then it pops out of it and runs fine.. does it every now and then only lasts a second or two or three.. LOL

You could try an aerial booster, Karen. You can sometimes get these for a couple of quid at a car boot sale and they might have 2 to 4 outlet sockets on them. Mine's got 8.

Don_1

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Re: Why does my digital TV freeze?
« Reply #10 on: 02/03/2009 07:23:11 »
Take it out of the freezer!

Good thinking, I'll give that a try!

I'm in North London and I get Channel 5 just fine on Freesat and analague...lucky me !!...nyahh nyahh !! *blows raspberry then runs away*

Heavy rain can cause problems ...has it been raining on your aerial ?


Freesat is not the same as Freeview.

Freesat signals are transmitted from a geostationary satellite and the transmissions are in the Gigahertz frequency range. And yes, signals may be susceptable to attenuation by rain if the dish is slightly off alignment or if there are any tree branches or other obstructions like overhead telephone wires in the way.

Freeview is a terrestial broadcast system which operates in the Ultra High Frequency (UHF) bands. The range is divided into three sub bands, group A, B, and C. For the London area your antenna would be group 'A' and your antenna should have a red plug identifying it as such on the end of the boom holding the aerial elements.

So nyahh nyahh back to you!!! (Blows raspberry and cleans mess of screen).

You are obviously 'marginal'. after switchover, you will get ten times the level of signal so you'll be fine. Patience, my dear.

Our signal comes from Crystal Palace, but we won't get Channel 5 until the switchover. Maybe I will just wait and see.

I suppose I could just pop along to Boots (other chemists are available) and get a bottle of Chanel 5!!!

FuzzyUK

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Re: Why does my digital TV freeze?
« Reply #11 on: 04/03/2009 22:58:01 »
Quote
Our signal comes from Crystal Palace, but we won't get Channel 5 until the switchover. Maybe I will just wait and see.

I don't understand what it is you are saying. These are the TV Transmitter channels radiated from Crystal Palace.  Freeview digital signals are marked (D):

22D, 23 (ITV1 Analogue), 25D, 26 (BBC1 London Analogue), 28D, 29D, 30 (CH4 London Analogue), 32D, 33 (BBC2 London Analogue), 34D, 37 (CH5 London Analogue).

CH5 however is NOT radiated via satellite, i.e. Freesat

ronnie

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Re: Why does my digital TV freeze?
« Reply #12 on: 02/09/2009 20:20:56 »
Take it out of the freezer!

Good thinking, I'll give that a try!

I'm in North London and I get Channel 5 just fine on Freesat and analague...lucky me !!...nyahh nyahh !! *blows raspberry then runs away*

Heavy rain can cause problems ...has it been raining on your aerial ?


Freesat is not the same as Freeview.

Freesat signals are transmitted from a geostationary satellite and the transmissions are in the Gigahertz frequency range. And yes, signals may be susceptable to attenuation by rain if the dish is slightly off alignment or if there are any tree branches or other obstructions like overhead telephone wires in the way.

Freeview is a terrestial broadcast system which operates in the Ultra High Frequency (UHF) bands. The range is divided into three sub bands, group A, B, and C. For the London area your antenna would be group 'A' and your antenna should have a red plug identifying it as such on the end of the boom holding the aerial elements.

So nyahh nyahh back to you!!! (Blows raspberry and cleans mess of screen).

You are obviously 'marginal'. after switchover, you will get ten times the level of signal so you'll be fine. Patience, my dear.

Our signal comes from Crystal Palace, but we won't get Channel 5 until the switchover. Maybe I will just wait and see.

I suppose I could just pop along to Boots (other chemists are available) and get a bottle of Chanel 5!!!

Nizzle

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Re: Why does my digital TV freeze?
« Reply #13 on: 03/09/2009 05:09:27 »
What a hassle -_-

We get digital TV over the cable. No weather dependency at all.

Don_1

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Re: Why does my digital TV freeze?
« Reply #14 on: 03/09/2009 07:14:01 »
I think its just another conspiracy, to get us to pay for TV.

Strange how BBC channels (which we pay for in our license) are OK, but independent channels all suffer from this freezing.

graham.d

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Re: Why does my digital TV freeze?
« Reply #15 on: 03/09/2009 08:32:38 »
The BBC owns the transmitters so they can grab more power I expect. I guess the Beeb have more clout with frequency allocations, polarisation and power).

Freezing of the digital picture and/or breakup of the picture into rectangles is due to poor signal and/or interference as has been said. Depending on the reason for the poor signal, an aerial booster (amplifier) may not help (i.e. if the signal is weak at the aerial the problem will be a poor signal to noise ratio; amplifying boosts both signal and noise equally. If you have a reasonable signal but wish to distribute it about your house, then there is good reason for a booster).

In my experience if the digital reception is subject to problems, you can usually see problems in the quality of the analogue reception too - noise or ghosting. Ghosting is due to multi-path reception and is often variable; for example, a signal being received directly and another weaker version coming from a reflection from a nearby tree. For good reception the aerial needs to be line-of-sight to the transmitter and then most of these problems disappear or can be cured with a higher gain aerial. Unfortunately many people cannot achieve this so these problems abound.

If the problem is just occasional freezing, but generally the picture is good, it is most likely to be an interfering bit of equipment (like a central heating boiler switching on for example) briefly saturating the input. Keep the TV and aerial away from such equipment and check that there is suitable suppression on the electrical noise coming via the mains. Kitchen TVs often suffer from this because of the amount of switched electrical equipment nearby.

lyner

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Re: Why does my digital TV freeze?
« Reply #16 on: 03/09/2009 09:12:03 »
I think its just another conspiracy, to get us to pay for TV.

Strange how BBC channels (which we pay for in our license) are OK, but independent channels all suffer from this freezing.
I think it probably depends upon where you live and which Transmitter you are looking at.  But in Brighton, too,  the mainly ITV digital transponder gives poorer reception. The ITV analogue channels are, in fact, better than the BBC where I live.

It's OFCom, not the BBC who make the frequency allocations and this is a transitional period. Once the switchover is done, there will be much better signals for everyone.

I don't think the BBC would conspire on behalf of cable.

graham.d

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Re: Why does my digital TV freeze?
« Reply #17 on: 03/09/2009 10:10:00 »
Don, have a look at this website:

http://www.aerialsandtv.com/rowridgetx.html#FrenchTransmittersMap

It says people in N London pointing at Crystal Palace may get problems from French transmitters in the same line of sight. If you have got a direct line of sight to CP, then a higher gain aerial (more directional) may help providing the French transmitters are not directly behind CP. If your aerial is wobbling about, getting a new one would sort this too.

I live in North Kent and get very good reception. I also have a flat in Essex and the reception there is really bad. For some reason I can get really good signal on all the shopping channels but not on some of the ones I might want to watch. BBC, ITV, ch5 are OK, but cant get ITV3 and Virgin 1 is variable (for example) though Virgin +1 is OK.

ukmicky

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Re: Why does my digital TV freeze?
« Reply #18 on: 03/09/2009 16:00:47 »
Quote
Our signal comes from Crystal Palace, but we won't get Channel 5 until the switchover. Maybe I will just wait and see.

I don't understand what it is you are saying. These are the TV Transmitter channels radiated from Crystal Palace.  Freeview digital signals are marked (D):

22D, 23 (ITV1 Analogue), 25D, 26 (BBC1 London Analogue), 28D, 29D, 30 (CH4 London Analogue), 32D, 33 (BBC2 London Analogue), 34D, 37 (CH5 London Analogue).

CH5 however is NOT radiated via satellite, i.e. Freesat

I Live a mile from crystal palace and recieve all the channels but with all our antennas being inside the house reception is not to good
« Last Edit: 03/09/2009 16:02:23 by ukmicky »

Don_1

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Re: Why does my digital TV freeze?
« Reply #19 on: 03/09/2009 16:26:19 »
Thanks Graham.

I live on the London/Kent border near Dartford.

I find all the BBC channels are good 99% of the time, but the independents are far more likely to break up. Ch5 is not available here on digital until 2010, only a poor signal on analogue.

It does seem that when the switch over happens, all signals will be up to full strength, but I can't see why this is not the case now. Then we would all know if any new equipment is needed and could sort it out now.

If there are problems for people upon the switch over, which aren't rectified by it, there will be an almighty rush to get things sorted.

lyner

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Re: Why does my digital TV freeze?
« Reply #20 on: 03/09/2009 22:43:27 »
The problem is that the new digital transponders are sharing the UHF bands with the analogue service. The original UHF TV plan was for 4 programmes. It does a fair job of providing a service to nearly everyone with enough signal and minimal co-channel and adjacent- channel interference.
A fifth channel was added in areas where it could co-exist safely. Now they have shoehorned a whole extra network of digital channels into the same spectrum space. That's a bit of a miracle and gets away with it because the digital signals appear to the analogue receivers as  noise ( snow) which is fairly acceptable at low levels. But there is a limit and the existing service takes second place until switchover, I'm afraid.
After that, we'll all get plenty of signal.

Geezer

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Re: Why does my digital TV freeze?
« Reply #21 on: 03/09/2009 23:19:10 »
Take it out of the freezer!

Cheeky bisom!

Don_1

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Re: Why does my digital TV freeze?
« Reply #22 on: 04/09/2009 07:10:06 »
The problem is that the new digital transponders are sharing the UHF bands with the analogue service. The original UHF TV plan was for 4 programmes. It does a fair job of providing a service to nearly everyone with enough signal and minimal co-channel and adjacent- channel interference.
A fifth channel was added in areas where it could co-exist safely. Now they have shoehorned a whole extra network of digital channels into the same spectrum space. That's a bit of a miracle and gets away with it because the digital signals appear to the analogue receivers as  noise ( snow) which is fairly acceptable at low levels. But there is a limit and the existing service takes second place until switchover, I'm afraid.
After that, we'll all get plenty of signal.

Ah! That explains it. Thank you.

techmind

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Why does my digital TV freeze?
« Reply #23 on: 06/09/2009 18:50:41 »
In much of the UK the digital signals are currently transmitted at lower power than in the analog equivalents, and the independent multiplexes (especially Mux D) has weaker error-correction and may be at even lower power too. So basically all else being equal, at present, digital can still struggle when analog is ok.

That said, aerials (especially if exposed to the elements outdoors) can degrade over time, and water can get into the cable, and the cables get eaten by rodents... so having a new aerial and cable may be no bad thing. Note that a lot of the wall-mounted aerial sockets are incredibly shoddy and will loose a lot of signal as are many common flyleads which go from the wall-socket to the receiver - they can also develop loose connections over time, which may not be immediately apparent on analog but can be enough to push DTT over the 'digital cliff'.

lyner

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Why does my digital TV freeze?
« Reply #24 on: 06/09/2009 21:24:13 »
Are you offering to fix my installation?
(That's not a euphamism. Btw.)

 

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