With the analogue (now closed down) television services, the picture quality degrades "gracefully" in proportion to the signal strength. It is possible to have watchable pictures with surprisingly low signal strength. Reflections are often only a minor irritation, leading to ghosts on the picture and a variation of picture quality between channels, which many are happy to put up with. Indoor and loft aerials used to give acceptable performance in some cases.
Digital television is a whole different matter. No longer do we have the luxury of being able to say "that will do". If there is insufficient signal level, the result is a picture that breaks up into mosaics and vanishes. The sound is also subject to squeaks and bangs as the level varies slightly. For this reason, the aerial system needs to be of an approved type and installed to a standard laid down by the CAI and the BBC etc. It is vitally important that a digital analyser is used for setting up the aerial and the signal levels balanced to provide reliable service. In some areas, some channels may not be able to be received and in others there may be no digital service whatever, Areas only covered by repeater statons will generally only receive about 60% of the full range of channels
The roof covering and end gables of a house can shield the aerial from the incoming TV signals. This can make a big difference to the quality of your picture. A roof which is covered with metal tiles, or roof insulation which contains metal, can destroy signals completely, making loft aerials pointless. With analogue television signals, a poor signal used to cause a grainy or snowy picture. With digital signals, it may be impossible to receive anything at all. A poor signal on FM will sound noisy and may drop in and out of stereo.
Lofts will usually contain household items which can reflect the incoming signals, even where there may be adequate signal strength. Water tanks, pipes, cables, and all the clutter a household can generate tend to be stored there. Signals are often reflected from these items and the reflections will cause a ghosting picture on analogue TV. With digital TV, the reflections may well lead to loss of picture. FM radio will suffer from 'birdie' noises etc.
Bear in mind that you normally have little control over your neighbours, so if they move or add to the 'junk' in their loft, it may well affect *your* viewing.
As a rule, the cable pre-installed into houses will be of the lowest possible cost to the builder, and will show high loss combined with poor screening. In strong analogue signal areas, this may be less important, but where the signal is borderline, or digital TV is required, it will NOT be good enough.
To obtain the best performance from a television signal, mount the aerial outside, in clear line of sight to the transmitter. Use a good quality aerial with integral balun, and feed the TV using a high grade cable such as WF100. The european standard for this cable is EN50117. This is now mandatory for new house builds and renovations.
AJL have been involved in the aerial and satellite business for over 28 years. We use only branded equipment from the likes of Triax, Televes and Webro that have passed "Benchmark" testing and have been issued with a certificate of conformity by the CAI.
Each installation is carried out with care and expertise, using the CAI guidelines as a minimum standard. On completion of the work, we issue our own certificate showing the measured performance of the system.
Product no.: DIGINOVA
Televes Diginova. TV, FM and DAB band coverage. The Diginova Boss antenna is the only radomized antenna of low visual impact that, automatically, optimizes the installation.
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