Freeview Reception Advice

freeviewhdThere are many factors that can affect the reception of Freeview channels and the multiplexes that carry them, some may only be temporary, others may be more troublesome.
Before investing in any new equipment, start by checking  coverage for your area at the Freeview website, type in your postcode and house number to see which services are available in your area.
if it shows you have good coverage or have previously had good reception, most problems can be easily resolved by doing the following:

1. Check for temporary transmitter faults or planned maintenance
Check the Digital UK website for details of planned engineering works that may be affecting reception in your area.
If your neighbours are also having problems, this is a good indication that a transmitter fault may be to blame.

Check the BBC website to find out if faults or maintenance are affecting BBC transmissions, channels such as BBC One and BBC Two are on a PSB multiplex, they are available to the whole of the UK.

2. Retune your digital TV or box and check that your cables and connections are not faulty
If there is no known transmitter fault or engineering work, then try unplugging your digital box or TV and then retuning it once the the connection to the power has been restored.

Take a good look at your cables. Are they worn or damaged? Check your equipment, are other TVs affected by the same kind of reception problems, your equipment may be faulty.

3. Find out if there is a problem with your aerial
If you are still having problems, then you may find that your aerial has been damaged or has become mis-aligned.

For advice on aerials contact a local contractor. The following organisations can give you details of one or more members who operate in your area and guarantee their work:

Confederation of Aerial Industries (CAI)
Find a digital professional at getmedigital.com

A local installer will understand the circumstances and local geography in your area and suggest the best option for you.

Check the following sites for more reception information: 

Coverage Checker (Freeview)

Planned Engineering Works (Digital UK)

Reception problems (BBC)


 

Coverage

transmitterOfcom estimates that the coverage level of the three public-service broadcasting (PSB) multiplexes reaches 98.5% of the population (the same as analogue television) and seven-multiplex reception covers 90% of the population post digital switchover.
The full package of Freeview channels (seven-multiplexes) is only available via the main transmitter in each transmitter group, and a number of other Relay Transmitters that are deemed to be important in terms of the large coverage area they serve.
Those who rely on a local self-help relay transmitter, or other Relay transmitters covering a small village or area only receive the three main Public Services muxes, PSB1, PSB2 and PSB3 (often referred to as ‘Freeview Lite’).

Freeview Lite refers to those areas only served by the public service multiplexes. These areas are served by relays and not by the main transmitters. Commercial multiplex operators have decided that in certain areas (due to their small populations), that it is not economically viable to broadcast their services to certain (mainly rural) areas. 
Viewers with limited or poor Freeview reception, can receive more channels on satellite, either through Freesat or Sky or Freesat.


 

Freeview Lite

freeview-liteWhat is referred to as ‘Freeview Lite’, is actually the three PSB multiplexes, PSB 1 operated by the BBC, PSB2 operated by  ITV plc and Channel 4 and PSB3 operated by the BBC.
PSB3 transmits in DVB-T2 and contains simulcasts of the PSB channels in HD.

These three Public Service multiplexes are obliged by their public service status to reach 98% of the UK population, this is in contrast to commercial multiplexes which have no such obligation and broadcast where it is considered commercially viable. It is up to the individual operators to decide whether or not their mux should be made available to rural areas via relay transmitters.
Most affected, are northern and central Wales, the Scottish Highland and islands, parts of England, the Isle of Man and the Channel Islands.

This could change in the future, as multiplexes migrate to DVB-t2 and PSB standard channels are replaced with a HD versions.
An aerial upgrade could also be an option in some areas, allowing reception of the commercial muxes.

Viewers with limited or poor Freeview reception, can receive most Freeview channels, though not all, on satellite, either through Freesat or Freesat from Sky.


 

Aerials

aerial1Freeview services are best received using directional aerials installed outside the building, ten metres above ground level. Always use an outside aerial, with attenuator if necessary, to achieve optimum interference-free reception.
Aerial quality is a major factor in achieving and maintaining good, interference-free reception. The recommended type of aerial is one that meets a recognised standard of quality and performance, such as the CAI Aerial Benchmark.
The measured signal strength at the termination of the down lead should be 45 to 65 dB when measured with a suitable meter. To allow for variations in signal strength and to ensure optimum results, the signal strength should be 6 dB above the minimum recommended level. Consistent results cannot be expected if the minimum signal level falls below 45 dB on DTT multiplexes.

There are planning restrictions on outdoor aerials in some areas. Where this is the case, the best alternative is a loft aerial, although generally it will not offer such robust reception; this is mainly due to the reduced height of the aerial and the attenuation of the signal through the roofing material. Some concrete tiles, for example, can reduce UHF television signals by as much as 20 dB because of their high metallic content.

A set-top television aerial is far less likely to be satisfactory; the signal it receives will be considerably poorer than that provided by a rooftop aerial and it will be far more prone to receiving interference.


Life Expectancy

Aerials and cable deteriorate with time, causing sudden or gradual loss of the signal. Aerial systems generally last for seven to ten years.
A number of factors affect the life of an aerial system, including:
• the quality of manufacture and installation;
• use at exposed locations;
• water ingress;
• corrosion from the atmosphere (e.g. in seaside and industrial areas); and
• bright sunlight.
Direction and polarisation

The aerial should be mounted using the appropriate polarisation, and directed towards the transmitter that provides the best reception.
Broadcast organisations such as the BBC, the DTG and the ITC supply data on the appropriate transmitter to use. Reception of signals from other transmitters outside the service area may be possible, though the quality of service is unlikely to be good and cannot be guaranteed.

The directionality of an aerial may not always be enough to achieve good reception. Vertical and lateral positioning may be needed; a cranked arm-mounting pole can be useful in these circumstances.


Aerial Types

If an aerial has a coloured bung it is a grouped type. The vast majority of aerials with a black bung are widebands, the elements for the A group are the longest because it is designed to be resonant with the lowest frequencies, which have the longest wavelengths.


Group A (Red)

A Group A Aerial is designed to operate on the group of UHF TV channels from Ch21 to Ch37, making it suitable for use on transmitters which transmit Freeview within this lower frequency channel group.

A Group A Aerial will significantly outperform a wideband TV aerial, delivering up to four times the signal to your TV, since it is designed for a narrow group of frequencies and has much higher signal gain and better directivity to minimise multipath interference.


Group B (Yellow)

A Group B Aerial is optimised to provide maximum gain on UHF Ch35 to Ch53, making it suitable for use on transmitters which transmit Freeview multiplexes within this middle frequency channel group.

UK TV transmitters requiring a Group B TV Aerial include: Heathfield, Bluebell Hill, Moel Y Parc, Sutton Coldfield, Emley Moor, Hannington (after digital switchover), Redruth, Wenvoe and Black Hill.

A Group B Aerial will significantly outperform a wideband TV aerial in its operating frequency range, delivering up to four times the signal to your TV, since it is designed for a narrow group of frequencies and has much higher signal gain and better directivity to minimise multipath interference.


Group C/D Aerial (Green)

A group C/D Aerial is designed to operate on the group of UHF TV channels from CH48 to CH68.


Wideband Aerial

A wideband TV aerial is designed to receive all available TV channels (Ch21 – 68) with consistent performance.
These usually have 52 elements providing a higher gain to improve Freeview reception in poor signal areas. It suits locations with nearby obstructions like hills and buildings result in a weak digital TV signal.
Wideband aerial are required for reliable Freeview reception in many areas of the UK, though wideband aerials are not the best choice for all regions.

Check to see which group is used by your local transmitter group, a dedicated group aerial provide significantly more gain than wideband aerials.


 

Direction & Polarisation

The aerial should be mounted using the appropriate polarisation, and directed towards the transmitter that provides the best reception. Broadcast organisations such as the BBC, the DTG and the ITC supply data on the appropriate transmitter to use. Reception of signals from other transmitters outside the service area may be possible, but the quality of service is unlikely to be good and cannot be guaranteed.

The directionality of an aerial may not always be enough to achieve good reception. Vertical and lateral positioning may be needed; a cranked arm-mounting pole can be useful in these circumstances.


 

Amplifiers

Amplifiers can generally be classified into three categories: masthead amplifiers, setback amplifiers and distribution amplifiers.

Used carefully, amplifiers can resolve particular reception problems – though indiscriminate use can sometimes make matters worse. The wide bandwidth of many amplifiers may cause them to amplify both wanted and unwanted signals, with resultant interference effects.
Excessive amplifier gain will also overload the equipment (signal swamp).
An amplifier should be selected for the specific installation, and may need to be used in association with attenuators and/or filters. Ideally, amplifiers should be screened and low-noise, and connectors should be of a suitable quality.


Masthead Amplifiers

In some situations, such as with a long cable run, a masthead amplifier can give a worthwhile improvement to reception. It should be used only where the off-air signal meets the required DTT reception minimum at the aerial, and after every effort has been made to increase the signal level by other means (such as adjusting the location of the aerial or using an aerial of a higher gain).

The amplifier should be mounted as close as possible to the aerial while avoiding feedback problems. The amplifier gain should be the minimum required to overcome the cable losses. Care should be taken not to overload amplifiers.


Setback Amplifiers

Setback amplifiers are readily available and easy to install, so they are often perceived as a simple means of improving reception. However, they should be used with care. As the amplifier is at the bottom of the aerial down lead, it is unlikely to give much improvement to a weak signal because it also amplifies the noise. This type of amplifier is frequently broadband, so is susceptible to problems resulting from cross-modulation.


Distribution Amplifiers

Broadband distribution amplifiers supplying multiple outlets can amplify unwanted signals outside the television or sound broadcast bands. In locations where there are strong signals from broadcast or other types of transmitter, use of a channelised amplifier and/or a suitable filter may be necessary. If any of the amplifier outlets are unused, it is important to ensure that they are correctly terminated.

Share Button