4G and TV Issues
Roll-out of LTE (4G) services in the 800MHz band previously used for UHF television services will begin in 2013.

UHF TV amplifiers that are currently in use are at risk of being overloaded as they will be amplifying the signals in the LTE band in addition to the current DTT signals.

It is recommended that amplifiers currently in use are removed as in almost all cases they should not be needed for the reception of DTT signals. All planning for the DTT network has been done on the assumption that amplifiers are not used.

In the small minority of cases where an amplifier is required, a good quality LTE filter should be inserted between the antenna and any other device that may be part of the TV system as shown in the diagram below.

In the unlikely event that no amplifier is used but the TV or SAORVIEW box is still overloaded it may be necessary to install a filter directly at the input of the receiver.

LTE filters are currently available from reputable TV equipment suppliers.
Filter installation
Installer Implementation Guidelines
These guidelines only relate to DTT systems in the presence of mobile telephony signals at 800MHz. They are not intended for installations of cable systems and satellite installations.

Background
LTE/4G Mobile networks have been licensed to operate in the 800, 900 and 1800MHz bands. The 800MHz band frequencies were previously used for services of analogue TG4 and TV3. Some existing aerial installations may thus suffer from overload and blocking effects as the existing aerial systems and many DTT (SAORVIEW/Freeview) receivers were built for sale at a time when these frequencies were still used for DTT in Europe.
Some aerial systems may have been fitted with mast head amplifiers in order to overcome co-axial cable losses in the downlead, or to receive deflector services or overspill services from the UK and NI.

When used with care, amplifiers can resolve some reception problems but if not used properly they can make things worse. The wide bandwidth of many amplifiers can cause them to amplify both wanted and unwanted signals. Too many signals and the amplifier will overload. Too much gain and it could overload the television. RTE advise that mast head amplifiers should not normally be needed to receive SAORVIEW services. The network has been designed for adequate reception at 98% of households with a suitable aerial at 33 ft (10m) above ground. In very rare cases aerials may need to be positioned higher in order to overcome some local obstacle causing a signal shadow. In certain situations, such as where a long cable run is unavoidable, a masthead amplifier can give a worthwhile improvement.

Steps to take where SAORVIEW reception deteriorates
Confirm that the aerial is pointing in correct direction and has not been blown off alignment due to wind or otherwise misplaced. Check that the co-axial cable used is low loss screened cable.
1) Check whether the prevalent meteorological conditions are of high pressure. These conditions would have given rise to co-channel interference in the past but can result in complete failure of reception of DTT. The steps outlined in this guide are not suitable for solving problems due to high atmospheric pressure.
2) Check whether the existing aerial installation has an amplifier between the aerial and SAORVIEW TV/STB. Determine whether the SAORVIEW signal in the area is adequate for reception without an amplifier and remove the amplifier if it is not needed. In the rare event that an amplifier is still required, it should be a screened amplifier and a suitable (Ch. 59 LTE reject) filter should be placed between the aerial and the screened masthead amplifier.
3) The removal of any unnecessary amplifiers and the removal of the associated power supply located indoors may improve reception as such amplifiers could be suffering from signal overload and generating spurious signals.
4) Where problems persist it may be necessary to fit a suitable (Ch. 59 LTE reject) filter between the Aerial and TV/STB.
5) Where these steps do not solve the problem, it may be necessary to point the DTT aerial to receive a different DTT transmitter where available or move the aerial to shield it from or, otherwise, adjust it, to null out the interference.

Multi-room installations
It is common practice to install multiple televisions in houses. The simplest approach householders may use is set top aerials on each TV. This has the advantage in high signal areas of avoiding significant cabling through out a house. However each TV may require a filter where a house is located very close to an LTE cellular base station. As an alternative, households may choose to install a passive signal splitter or multi-way distributor and run co-axial cable into various rooms.
Any LTE Reject filter should be placed between the aerial and the amplifier or before any splitter where an amplifier is not fitted.
Where DTT typical signal levels exist a Distribution amplifier, similar to a masthead amplifier, might be used to make up for the losses in cables around the house as well as splitting the signal to a number of different televisions. Distribution amplifiers do not improve the signal and will fail to work unless there is an adequate quality signal available to work with. Care needs to be taken that amplifiers do not amplify the signal too much as DTT receivers will also fail to decode signals where a DTT signal is too strong.
It is essential that where a distribution amplifier is used, any LTE reject filter installed should be placed between the aerial and the distribution amplifier. In multi-storey communal installations consideration should be given to installing a filter prior to any splitter or amplifier placed on each floor.
Care needs to be taken that any internal cabling and fly leads are of a suitable standard, e.g. double screened CT100. Even if a filter is used before signals are split for multi-room distribution, LTE signals could enter via poor quality leads in the internal cabling or between wall sockets and DTT receivers. Wall sockets should be checked to ensure that the hidden co-axial cable behind the wall/plaster is appropriately connected to the socket and that the socket is of a screened design suitable for the wall installation.
Filter Availability
As the rollout of cellular mobile telephony services is taking place all over Europe in the 800MHz, appropriate filters, banded aerials and training material are widely available from reputable suppliers.

You can buy a 4G LTE Filter kit here