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Do I need to buy a booster?

With analogue television, it has often been necessary to buy an amplifier to improve the quality of the television picture, or to supply a steady on several televisions fed from the same aerial.

With analogue television, it has often been necessary to buy an
published on UK Free TV

With analogue television, it has often been necessary to buy an amplifier to improve the quality of the television picture, or to supply a steady on several televisions fed from the same aerial.

Many people have asked if it necessary to investing in a signal booster for Freeview.

"Analogue television" means is that the sound and pictures are broadcast using signals that are an "analogue" of the input. The sound and picture are transmitted from the source as electrical signals, then as radio waves and then back to sound and picture again.

In an analogue television camera, the image is scanned 25 times a second from side to side, from top to bottom and back. Where a lot of light is scanned, a high voltage is produced. Where no light is scanned, no voltage is produced. The output voltage is the same ratio to amount of light at scanned.

Leaving aside the technically, this signal is sent to the transmitter. The transmitter emits a radio wave on a known frequency, which is varied by the incoming voltage.



A microphone also converts the sound vibrations it picks up into a voltage, which when sent to the transmitter is added to another radio transmission frequency.

The signals are received by a television aerial pointing at the transmitter and converted back to very weak electrical signals. The sound is amplified and sent to a loudspeaker, and a picture created on the TV screen.

So on an analogue television, if the incoming signal is weak then the picture is dull as the background noise (the snow scene seen when an analogue television is not tuned) makes the picture less watchable.

The best analogue television set equipped with a great TV aerial located near to a high powered transmitter will produce brilliant pictures and clear sound. A poor set with an inadequate aerial or substandard cable will not.

If a weak signal is fed to a booster device, this will make the picture appear better on the television set or sets. It is often worth the investment.

Digital television


In a digital studio, the voltages from the cameras and microphones are not sent directly to the transmitter. It is converted into a stream of numbers inside a computer. The input voltage relates directly to the number in the computer. By sampling the input at a regular frequency, it is therefore possible to both store and transmit the information digitally this is what computers are good at.

It is therefore possible to take these numbers and generate a sound and picture output from them. However, the amount of information generated is over 240Mb/s, 30 times the rate of the fastest broadband connection.

Buy using computational techniques on this information the data can be compressed to as low as 2Mb/s, with as little as 6Mb/s being required for a good quality picture. These data compression techniques are called "lossy" because the reconstructed images are not identical to the originals, but look virtually similar to human eyes.



Digital television uses the same transmission frequencies as analogue uses, known as C21 to C68. The digital data is sent using a system called COFDM (Coded Orthogonal Frequency-Division-Multiplexing) which can carry data at a rate of 18Mb/s or 24Mb/s. Several television channels and some radio stations can be multiplexed together to produce exactly this amount of data.

At the receiver, it must be able to decode every single bit from these transmission multiplexes. A single error is impossible to correct for, so the decoder must have no errors.

Until switchover happens, the Freeview signals are being broadcast at very, very low power levels. However the COFDM system and sensitive digital equipment will, as long as the signal can be found and decoded there will be pixel-perfect reconstruction of the television channel. If the signal is drowned out by interference (especially from analogue transmissions) then no picture or sound will be output.

If the TV aerial installation you have provides you with all the Freeview channels, there is nothing to worry about.

If you are missing some channels because the signal is just too weak the best place to start is by improving the aerial, see Freeview reception - All about aerials. A bigger, higher, better designed aerial will always be the most sensible way to get perfect reception.

If you want to supply a signal to several sets, where the incoming signal is being "split" to serve several Freeview boxes, a masthead amplifier will be effective. This is because the signal is already of good quality and is being repeated for several sets.

However, if you are not getting a good signal from your aerial, a booster by the TV set will probably not help as this will simply boost the background interference as much as the Freeview signal.

In circumstances where an amplifier that has improved a picture on an analogue, it may be unsuitable for Freeview reception. Sometimes they will block one or more multiplex, where disconnecting the amplifier will restore the channels.

Help with Television sets?
Why are all TVs on sale not digital?1
Do I still have to pay for a TV licence?2
I had perfect channel 5 reception - until I got a digital TV box!3
I Have a Pocket Tv For taking out so I can keep up with news and sport. Will thi4
The pictures from my digital box are all green!5
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In this section
Loft aerials1
How to receive Freeview on your PC2
Indoor aerials3
Whole house digital TV4
Connecting it all up5
Now and Next6

Comments
Wednesday, 13 April 2011
A
Alan
9:40 PM
Largs

Thinking of buying Full HD Freeview ready television.STV central area switches over in June.Current analogue signal requires amp does this mean that I may require an improved ariel which is sited on the roof?

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Alan's 1 post GB
K
KMJ,Derby
sentiment_satisfiedGold

10:46 PM

Alan: If you currently have good analogue reception you should be ok with digital signals after switchover.Wait and see is probably the best course. Note that if you use the relay transmitters at Largs or Rothesay you will only be able to receive the 3 PSB muxes. (Freeview Lite). If you require any additional channels you will probably need to consider obtaining a satellite receiver.

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KMJ,Derby's 1,811 posts GB
Thursday, 14 April 2011
Friday, 22 April 2011
K
Kenny
8:58 PM

Have got sky hd for tv in living room, and 2 other tvs in house (all are digital freeview, and reception is good from aerial in loft). Have got sky on return from living room via mast head box in loft to other tvs - this comes through on analogue which is ok, just want to be able watch sky in other rooms etc. However, picture quality on sky return is poor on other TVs and have 'magic' eyes to change sky channels in other rooms but they don't work - any views?

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Kenny's 1 post GB
Saturday, 23 April 2011
Briantist
sentiment_very_satisfiedOwner

7:16 AM

Kenny: You can only have a single "Magic Eye" connected to the RF2 output.

link to this comment
Briantist's 38,844 posts GB
Sunday, 24 April 2011
S
Sue Prevost
7:32 PM

I can no longer get Channels 10, 12 & 15 on my freeview - it just says no signal. Is this an aeriel problem ? I have always been able to get these channels - moved some things in the loft the other day and the aeriel got shifted could this be the problem ? All the other channels are fine. Man thanks.

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Sue Prevost's 1 post GB
Briantist
sentiment_very_satisfiedOwner

10:18 PM

Sue Prevost: Loft aerials are not really suitable for Freeview reception.

It is hard to advise without a postcode.

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Briantist's 38,844 posts GB
Saturday, 30 April 2011
A
Alyson
11:57 AM
Chesham

hello i want to put a tv in each of my childrens bedrooms but i dont want to pay for sky. i am happy for them to just have freeview channels. what is the best way to do this? i am told that the ariel reception in our are isnt very good HP5 1SS. please can you give me some advice

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Alyson's 1 post GB
Sunday, 1 May 2011
W
william
2:08 AM
Nottingham

hi i have a tv in bed room and tv in kitchen we have lost channels and picture starts to break up to kitchen tv sony bravia we have external digital ariel and cable run into loft to splitter then to each set.ariel is 3 years old have we a ariel problem or do we require a booster thanks PC NG2 5JP

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william's 1 post GB
Tuesday, 3 May 2011
B
Brian Croft
10:31 AM
Nottingham

I am unable to receive the Freeview Multiplex Channel '2'
ITV1,Ch4,CH5 etc. This has only happened over the past few days. I have tried, unsuccessfully to retune all my Digital TVs and Recorders with no success. I can receive ITV1,CH4 and Ch5 analogue fine.
My post code is NG12 4FA. I would appreciate any advice/assistance you can provide please.


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Brian Croft's 1 post GB
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