Which transponder to use

Some newer cars are also equipped with ones that operators can use to locate the vehicle in the event of an emergency. Cellular phones use a similar, albeit smaller, chip to send the phone's location if it used to call an emergency number. Even casual television viewing often involves the use of these devices. A network can uplink its ground-based satellites to communications satellites orbiting the Earth, send multiple channels of digitally compressed video and audio to a single transponder aboard it, and local stations can then pick up the program and re-broadcast it locally by aiming the appropriate ground-based dish.

Please enter the following code:. Login: Forgot password? Subsequently, transponders have come into widespread use in civil as well as military aviation. It is now standard practice to allocate a specific transponder code to each aircraft flying in controlled airspace so that the ATCO can readily identify a specific aircraft on a crowded radar screen, using SSR Secondary Surveillance Radar.

By international agreement, is used for aircraft which have not been assigned a transponder code, although in some parts of Europe, is used for this purpose. A number of large airports have included information in the Automatic Terminal Information Service ATIS broadcasts when the transponder is required to be active for taxi operations.

If you are still having problems, it is possible an unwanted signal is the cause. For information on the symptoms of interference see our sister website RTIS. The BBC cannot recommend individual installers. The CAI Confederation of Aerial Industries is a recognised trade body which will be able to put you in touch with one of their members in your area.

You may need to contact your car manufacturer to check. The best place to put a DAB aerial is on the roof of the car and as far from the engine as possible, to avoid any interference. If your car radio is showing no signal or no service for a station you usually receive, this could be down to one of the following things:. DAB Transmitter Fault. If you know your location, you can use our transmitter checker to see whether there is a problem.

If not, then check the radio and the aerial to confirm they are working correctly. Poor DAB reception can also be caused by equipment used in the vehicle.

For example, phone chargers or dash cams sometimes cause interference and affect your radio signal. Try unplugging the items to see if one of them is causing any interference.

Delete the presets and re-tune to the services in your area. When travelling in the car, your signal can be affected by natural features of the land, for example, hills, valleys, rivers, etc. The signal should return once you move away from these features. Where can I find them? When Radio 5 Live Sports Extra is on air, you should find it right next to 5 Live on the list of stations on your digital radio.

It can be found next to Radio 4 on the list of stations. When do they broadcast? Radio 5 Live Sports Extra has a dynamic schedule. To see what is available when, the BBC keeps a schedule on the sport website. How to find these services.

It is best to re-tune your radio when they are broadcasting, so it will store the station in its memory. It is worth first checking to see whether the problem is with your own equipment, or the local transmitter.

If neighbours are having the same problem it may be that the aerial itself is at fault, or there may be an interfering signal. In either case, you will need to ask your landlord or management committee to solve the problem.

Checking for problems. Check cables and leads within your property to ensure the problem is not a simple installation fault. Please see our Freeview Installation guide for further details. This will help you to see if there are, or have been recently, transmitter faults in your local area. Electrical interference.

There are differences between a reception problem and one caused by electrical interference. See our help guides which explain the differences. If it is potentially interference, your landlord or management committee can contact the regulator, Ofcom, for help with solving the problem, using their contact web form. Since it is a communal aerial, you will not be able to contact Ofcom directly.

Your television can sometimes receive signals from more than one transmitter, which may be transmitting different regional news. This is more likely to occur following a retune of your television. To ensure you are receiving the correct regional news programmes from the transmitter your aerial is pointing towards, you will need to do a manual retune. Please see our help guide on a manual retune. Please be aware most local news is not currently broadcast in HD at this time so will not be available on HD channels.

Please use our Transmitter tool to see if you are in coverage. Following a decision by the Government, some channels used by Freeview, are being reallocated to allow for the future development of new mobile broadband services. This may be due to two reasons. Firstly, you may have a poor aerial system, so we recommend you checking over your installation by reading our Good installation help guide. Secondly, you may be on the edge of Freeview coverage, and likely have a weak signal.

This may be fine during the day, but in the evening, signals from distant transmitters can travel further, and can cause reception problems for those at the very edge of coverage.

Use our Transmitter checker tool to see if you are in an area of good reception and for further advice. For programmes which are pre-recorded, we create the subtitles in advance. For a programme broadcast live, like the News , subtitles will be generated as it is broadcast, which is a complex and problematic process. Audio Description is a live verbal commentary, providing information which describes the key visual information contained on the screen, which a blind or partially sighted viewer may otherwise miss.

To turn AD on or off, press AD on your remote. For more helpful information please see our Audio Description help guide. There are all kinds of aerials available on the market and some which are specific to certain frequencies. A wideband aerial is a popular choice, although there are other aerials available. A qualified aerial installer with local knowledge will be able to advise further. Your aerial should be as high as possible pointing towards the transmitter with the best signal.

Ensure there is nothing in front of the aerial that could block the signal, such as trees. All TV reception predictions assume an outside aerial at a height of 10m from the ground. Loft and indoor aerials. If you live close to a transmitter or can get a strong TV signal, then it could be possible to use an aerial in your loft or an indoor portable aerial. However, in both cases the signal will be weakened as it has to pass through various obstructions such as walls, roof tiles, foil backed insulation etc.

Even if you are predicted to have good reception, you may have problems receiving services using indoor or loft aerials. Cable and connectors. A television signal will always lose some of its strength as it passes along the cable and through the connectors. Therefore it is important to minimise the loss by using good quality cable and connectors.

These are not recommended unless absolutely required as they can introduce unexpected reception problems. See our help guide on the different types of amplifiers available. Depending on the transmitter you are using, your aerial elements will need to be mounted flat horizontal or on its side vertical. We cannot recommend individual installers. However the CAI Confederation of Aerial Industries is a recognised trade body which will be able to put you in touch with one of their members in your area.

Basic Installation. It is important to check that your installation is intact. For example all the cables between your television equipment and aerial are connected securely and none is damaged. Further information is available in our Freeview installation guide. Check our Works and Warnings section to see whether there are any known problems. Using our Transmitter Checker , check your transmitter is not undergoing any work. Television signals can be affected by fine weather including high pressure atmospherics and the only solution is to wait for the weather to change, you should not retune during this time.

See how weather can affect Freeview reception. During wet weather, when covered in moisture, all trees can have an appreciable effect on signals. As trees sway in windy weather the screening effect varies, leading to fluctuations in the quality of reception. To rule this out see our guide on cables and water damage. A manual retune is more effective than an auto-retune as it only tunes your television to the transmitter your aerial is pointing towards. For more information on how to retune manually see our manual re-tuning page.

For information on the symptoms of interference see our other site, RTIS , for further information.

We cannot recommend individual Installers. When to use an amplifier. A signal amplifier should only be used as a last resort when the television signal is weak. A good amplifier should have a filter built in that only allows the signal you want to be boosted and not any unwanted signals.

Otherwise, all the unwanted signals will also be boosted, which can cause pictures to break up. Problems using amplifiers. Amplifiers themselves are a common source of reception problems. For example, if water were to get into a masthead type, they can start to boost the result of the fault.

This could be unwanted signals and result in picture loss on your own television and, maybe, those living nearby. To check, remove the power from the amplifier and see whether the problem goes away. There are three types of amplifier — masthead, set-back and distribution. All these need a power supply to work.

These fit directly under an outside aerial and usually the best type of amplifier to fix weak signals. These fit between the aerial socket in the wall and your television. These split the TV signal from a single aerial and allow the signal to be sent to several different televisions in the building.

Combined amplifiers. Some amplifiers are a mix of the above. For example, some masthead amplifiers are also distribution amplifiers. Some can also combine television and FM radio signals. When to use an Attenuator. If you are experiencing pixellation or picture break up, it may be that your signal is too strong as this often presents itself similarly to a weak signal. This is likely to happen if you live close to a transmitter.

Attenuators can be used to decrease the incoming signal if it is too strong without distorting it. It is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, boosts the signal, an attenuator provides loss, reduces the signal. Attenuators are always a compromise and should only be used if absolutely necessary. They come in a variety of powers; in most cases a small reduction is all that is needed.

It may take a little trial and error to find the most suitable one for your installation, and it is worth taking the advice of a local aerial contractor to select the correct one for the installation. A fire at the transmitter site has caused disruption to all services from the site. The process to restore services using a combination of temporary structures and existing infrastructure elsewhere in the region has started.

This incident is being managed by our suppliers Arqiva and we are working with them to ensure services in the affected area are resumed as soon as possible. For details on how Arqiva are planning to restore services, including the latest plans and timescales for the temporary transmitter, please see bilsdalemast.

On the 13th October Arqiva successfully switched on a new 80 metre temporary mast close to the original Bilsdale mast site. This brought back signal to thousands of homes across the region. In addition, two small relay transmitters were just added in the Loftus 30th October and Thirsk 31st October areas. If you are in an affected area you should retune to help restore channels.

For help retuning try this retune guide on Arqiva's Bilsdale website. Arqiva is offering a help scheme which includes tuning advice, a voucher scheme and help with aerial installations.

This scheme is available to all viewers who continue to experience reception problems since the incident at the transmitter.

More detail about the scheme can be found here. If you are still experiencing problems you can log an enquiry by entering your address into the postcode checker on the Arqiva help scheme website. There is also a Freephone number available on The line is prioritising calls from people over 65, to the clinically vulnerable and other vulnerable people with carers. BBC Radio Tees. If you had previously lost DAB services we recommend you rescan your radio, as the new temporary mast won't appear in the Transmitter Checker tool yet.

See our help guide to get the best reception, What is a good FM radio installation? Placing near the window can help as that will minimise the impact to the signal from building materials. Digital Satellite and Virgin users are not affected.

FM radio at Holme Moss has been undergoing antenna re-engineering works since the 29th June. Since the start of the re-engineering works BBC Radio 1, 2, 3 and 4 have been operating at reduced power. The work is complex and services will continue to be transmitted at reduced power for a further period. We do not as yet have a date when services will to revert to full power.

Please keep checking back to our website for further updates. Platforms affected include Freeview. Viewers may have difficulty with reception, however they can still watch their favourite programmes by using BBC iPlayer. The government set a target of switching off FM radio services after a set of criteria on digital radio listening had been met. The criteria has recently been met but as yet the government have not undertaken a review of FM radio nor given any indication of when or if FM switch off will happen.

This normally happens in the summer months, due to high pressure weather conditions in the atmosphere, allowing radio signals to travel further. The cause is an atmospheric effect known as Sporadic-E and can last from a few seconds up to an hour or more. For more information on how weather can affect your Radio services, please see our guide. At night medium wave radio signals can travel much further than during the day.

This means your radio is able to receive more radio channels either using the same frequency as the service you are listening to or adjacent to that frequency.

The result is a higher level of interference and a deterioration in both the sound and coverage. B asic Installation. It is important to check your installation is working properly and that your radio is in the best possible position. We have a basic installation guide to help you with this. Works and warnings. Check whether there are any known works or warnings that may be causing the problem.

Transmitter faults and frequencies. Use our Transmitter Checker to check the transmitter is not undergoing any work and to see which FM radio services you can receive from your location.

Hi-Fi radios. If you are using a Hi-Fi tuner and stereo reception is hissy, but mono is fine, your aerial may not be powerful enough.