Pixilation , Blocking ,on your TV why and the solution
One of the biggest problems with Digital TV is Pixilation problems.
On this web page I'm going to try and give you some idea on why this might be happening to your TV Signa.l
A digital picture quality is either very good or poor. One of the major problems with a digital TV picture is Pixilation or blocking or maybe freezing.
Picture of television screen with pixilation
The problem with the TV is that the signal strength coming from the aerial is too high or too low or it could be the TV itself. To see if it is the TV, just put another TV on the same aerial point and if you still get the pixilation problem then it's the aerial causing it. If you don't get the problem of pixilation on the second TV then it maybe the TV at fault.
The first thing that a lot of people will reach for is some kind of aerial amplifier or booster.
This can cause more problems with your TV signal. It can increase Carrier Noise in the signal which in the trade is known as the cliff effect. This means you could lose your TV picture altogether. If you had an amplifier fitted because your signal was low before digital switch over it could now be causing a problem giving too much signal! Try taking the aerial amplifier off and see if it makes a difference.
Without any kind of signal measuring equipment you will need to go dowm the road of elimination.
First of all go outside. If your aerial is on the roof take a pair of binoculars! Look at your Aerial. Are any of the elements missing, are the back reflectors still in place? Your aerial should look like the aerial pictured below
Picture of an aerial
If the aerial looks intact then look at the size of the aerial. Is it the same as the ones on the houses around you?
You could have a small aerial which means small gain.
Then start to look at the aerial cable coming down from the aerial .See if you can see any taped up joints or cuts. If you look at our section on aerial cables you can see the kind of things to look for.
Picture of a damaged aerial cable
At the end of the day a good aerial install without any amplification has a much stronger signal than an installation with an aerial amplifier or booster as you could just be amplifing a low rubbish signal which will give you all sorts of problems. If your aerial is in your attic space or loft then this also could cause a problem with low signal levels. So its always best if possible to get your aerial on the outside of the building as you will get a much stronger TV signal. As we said at the beginning of this topic you could also have too much signal. The best way to try and combat this sort of signal problem is to have a signal attenuator fitted as shown in the picture below.
Picture of an signal attenuator
The attenuator is fitted in-line with the aerial cable that plugs into your TV. With the television on, you can adjust the signal level by turning the little red screw on the end of the box. This will decrease the signal level. As you do this watch the TV and see if your pixilation stops.