5.2 Examples of common problems with receiving installationsThe following pages show a small selection of photographs taken during the BBC coverage survey in Weymouth and Dorchester that demonstrate some of the aerial faults that can occur. These poor quality installations will be responsible for some (but not all) of the poor television reception reported by viewers who responded to the questionnaire distributed by SWEDBAG. You can visually inspect your own rooftop aerial to see if any of these faults are likely, in which case they can be repaired by a registered Confederation of Aerial Industries (CAI) aerial installer [1]. In addition, if your aerial is a basic contract aerial (see Fig. 15) or a flimsy X-beam type aerial as shown in Fig. 17, it may benefit from replacement with a good quality ‘digital-ready’ aerial installation. Interestingly, in a couple of photographs, you can see sea gulls perched on roof-tops. They may be responsible for some of the damage to these aerial installations. Also it is worth noting that rooftop aerials have much shorter lifetimes in seaside areas where salt corrosion can seriously affect the metalwork of the aerials and can corrode the connections and downleads. Again a registered CAI installer should be able to restore good reception.
Fig. 16 - Aerial pre-amplifier (black coloured unit) is open to the weather allowing water to enter the cable downlead
Fig. 17 - Elements missing from the aerial (a flimsy X-beam aerial)
Fig. 18 - Reflector panel missing from the aerial
Fig. 19 - Aerial elements bent
Fig. 20 - Aerial pre-amplifier/splitter (red coloured unit) hanging in space
Fig. 21 - Aerial elements and reflector missing. Aerial not securely fixed to chimney stack. Spot the seagulls!
Fig. 22 - Aerial has moved since its installation and is now pointing skywards. Spot the seagull!
Fig. 23 - Reflector missing from aerial, aerial pre-amplifier/splitter (red coloured unit) hanging in space
Fig. 24 - The aerial reflector is not correctly positioned with respect to the elements
Fig. 25 - Aerial elements and reflector panel missing
Fig. 26 - Aerial elements missing and bent It is worthwhile stressing that even if an aerial installation looks fine, it does not necessarily mean everything is OK. Often water can get into the cable downlead which will cause a serious degradation in picture quality. The condition of the connection is also very important. An older cable downlead is also likely to have poor electrical screening properties which will make electrical interference on analogue TV or radio much more likely and could stop digital TV or radio reception altogether (or make it more vulnerable to interference from thermostats, light switches etc.). In this case, a registered CAI installer should be able to replace the downlead with one that is suitable for digital reception.
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