If you have an external aerial, a radio signal will always lose some of its strength as it passes along the cable and through the connectors. Ideally, this should be on the roof or high up on the outside of the building, though it may also give good results in the loft. An indoor aerial may be good enough, but for the best reception use an outdoor one. DAB aerials are different from FM or TV aerials, so you need a good quality DAB-specific aerial. Broken aerials may affect reception.Īn externally mounted aerial can be attached to many types of DAB portable radio and hi-fi systems. Tilting and swivelling the aerial will help to get the best signal. Telescopic aerials on portable radios should be fully extended to receive a good signal. From time to time radios should be re-tuned in order to discover new stations. Most DAB radios come with built in signal strength meters which can be helpful. Portable radios should be tuned in a location in your home where the best possible signal is received. Most DAB radios can be tuned easily at the touch of a button. If you live in a basement flat, or your building is steel-framed or reinforced concrete, coverage may be affected. Have a look at our Transmitter Checkerto see what BBC services you can receive where you are. Your radio must be in a good DAB coverage area to receive BBC services. We have a guide to help you manually retune. If you have re-tuned your television, we would recommend doing a manual retune to the transmitter your aerial is pointing towards. You should not retune your television when this happens. When we are aware of this happening, we will put up a news item on Works and Warnings.Īt these times, there is nothing that can be done but to wait until the weather condition changes. Nevertheless, when averaged over several years, the majority of viewers and FM listeners should be free from this sort of interference for at least 99% of the time, providing they live within the service area of their transmitter and are using a good directional aerial. Some years are worse than others, depending on the prevailing weather patterns. It often appears at the same time on consecutive days, then disappears for several months. It tends to happen mostly in the evenings - when television viewing is at a peak and specialist FM programmes are on air. Unfortunately, tropospheric-type interference is never spread thinly throughout the year. This is impractical and would be very expensive. To improve on this figure, broadcasters would need to increase the number of transmitters drastically and build a much denser network.
Since we cannot control the weather, we have no influence over abnormal propagation through the troposphere, and it is only practicable to plan a network where interference is suffered no more than 1% of the time. Example of how weather can impact television reception This can also happen with the television relays in our transmitter network which receive their signal from another transmitter. For more information see our guide on tropospheric ducting. Being able to receive more than one signal using the same frequency can cause problems such as pixelation. This is known as co-channel interference and can be caused by a weather effect called tropospheric ducting. Normally, the signals from each transmitter can only be received by those homes that have aerials with a direct line-of-sight to the transmitter.
Therefore, there will be occasions when certain weather conditions allow the signals carrying television services to travel further than expected. Therefore at these times, you can then receive different television services that are using the same frequency. However, as we only have access to a limited number of frequencies to broadcast television services, we need to re-use them numerous times across the UK. The television transmitter network is engineered to a very high level, so impacts due to the weather are rare.
The BBC has over 1000 television transmitters across the UK.
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