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Loft aerials

One of the most common problems people have with Freeview reception relates to the use of "loft" aerials.

One of the most common problems people have with Freeview recep
published on UK Free TV

One of the most common problems people have with Freeview reception relates to the use of "loft" aerials.

Because the analogue TV transmitter network uses very high power transmissions (the total ERP for the UK is 64 megawatts) many people have installed their TV aerial in places such as lofts, or have used other <img src="data:image/png;base64,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" class="xico" style="vertical-align:text-bottom" alt="www.ukfree.tv link icon"> link iconIndoor Aerials.

The effect on that roof tiles and walls have on analogue TV signals is that the picture will degrade slightly. Making the signal slightly weaker will add a 'snow' element to the picture which is mildly irritating. The picture quality drops, but it is usually possible to make out the picture, as demonstrated here:



Many people have preferred this slight loss in picture quality for the perceived benefits of a loft-mounted aerial. Loft aerials are much easier and somewhat safer to install, and the aerial is shielded from wind and rain that can cause damage to rooftop aerials. In some places (such as New Towns) TV aerials have been previously banned from rooftops.

However, the BBC and others state that Freeview reception demands a roof-top aerial. The existing (pre Digital Switchover) Freeview signals are at very low power levels. The use by ITV, channels/channel/C4">Channel 4 and five of "64QAM" mode for their transmission multiplexes to provide more channel choice results in a very lower chance of reception of these channels (multiplex 2 is ITV1, ITV2, ITV3, ITV4, CITV, Channel 4, More4, E4, Film4+1; multiplex A carries five, five Life and five US) with a loft-mounted aerial.

By comparison with the image above of how analogue signals look as the signal grow weaker, digital TV reception will continue to give perfect pictures and sound as the power level drops off, until suddenly the level drops below what the COFDM system can cope with. At this point the picture will become blocky and freeze whilst the sound will appear to come and go. Another tiny drop in signal level will result in no picture or sound and a message saying that "no signal is being received". As the signal can vary with weather conditions, people often find that a loft aerial will work when installed and then suddenly stop some months later.

After switchover

After switchover new digital signals will replace the existing analogue and digital ones. The new digital signals will be at much higher levels that the current ones (for most people) and this will help with reception. However, all six multiplexes will switch to the <img src="data:image/png;base64,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" class="xico" style="vertical-align:text-bottom" alt="www.ukfree.tv link icon"> link icon64QAM mode that causes the problems indicated above.

Due to our Climate Change commitments (Kyoto Protocol), the signal levels for these new digital will not be as high as those currently used for analogue. For this reason you should not depend on the increase in power levels after switchover compensating for having a loft aerial.

Wherever possible you should use a rooftop aerial. If this is impossible, you may find that connecting your aerial to your Freeview box or integrated digital television using satellite-grade coaxial cable will compensate for the loss.



Television sets?
What connections are used from set top box to TV (such as SCART) ?1
If you have several TVs at home do you need separate decoders for each set or is2
Can I use a Freeview box if there is no SCART connector on my TV?3
My TV is NICAM, does that mean I have digital TV?4
Why has my widescreen TV just made everyone look fat?5
In this section
Do I need to buy a booster?1
How to receive Freeview on your PC2
Indoor aerials3
Whole house digital TV4
Connecting it all up5
Now and Next6

Comments
Tuesday, 14 January 2014
J
jb38
5:58 PM

dave simpson: By the way as far as the aerial is concerned, its not so much a case of changing it for a better model but making sure that its positioned as far away from the source of interference as possible, this also applies to the powered booster / splitter.

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jb38's 6,181 posts Platinum Platinum GB
Thursday, 25 September 2014
K
Kelli
11:38 AM

I live in a new build flat in Stepany Green. There is a wall socket for the aerial. I use a freeview set top box and have scart cables. However the reception of various chsannels varies throughout the day - sometime no sgnal, sometimes broken picture, sometimes OK. Can you help me get a clear picture on all channels at all times? Many thanks.

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Kelli's 1 post GB
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