Codes & Guidance Notes

ITC Code of Practice on Changes to Existing Transmission and Reception Arrangements

Introduction

1. In order to accommodate the transmission plan for digital terrestrial television (DTT), there are certain changes which need to be made to the transmission and reception arrangements for the existing terrestrial television services. Details of the required transmitter changes and the predicted extent and location of interference to existing analogue reception will be notified by the ITC to the multiplex service licensees in the Joint Planning Project (JPP) detailed deliverables and confirmed in the subsequent D-TPG paper which will form the basis for national and international clearance of the assignment.

2. It is a condition of the national clearance of the digital transmission plan that the costs involved in carrying out these changes must be met by the relevant multiplex licensee. This Code of Practice sets out the ITC's detailed requirements in relation to these obligations. The ITC expects that where more than one multiplex provider has such an obligation relating to the same change on the transmission side, or to the same premises on the reception side, then the relevant work will be done co-operatively with each multiplex provider bearing an appropriate share of the costs.

3. Any interference or potential interference arising from DTT and covered by this Code will occur in one of the following categories, which are taken as headings for the sections of the Code that follow:

• Transmission Changes Only: Where the Deliverable notifies a need to change some aspect of the existing transmitting arrangement (e.g. the implementation of precision frequency control) which does not affect viewers.
• Changes of Existing Transmission Frequency: Where the Deliverable notifies a need to change the broadcast frequency channel for an existing service at the affected transmitter (this does affect viewers, who will need to have their receivers retuned to the new frequency).
• Changes in Reception Arrangements Only: Where the Deliverable does not notify any changes to be made to existing transmission arrangements, but where existing viewers lose a service in practice due to interference caused by DTT transmissions.
• Provision of a New Relay Service: Where the Deliverable notifies a need to provide a new transmitter in order to restore an analogue service to existing viewers who would otherwise lose a service due to interference caused by DTT transmissions .



A. Transmitter Changes Only

4. The need for transmitter changes under this Code will be notified to the licensee by the ITC in the Joint Planning Project (JPP) detailed deliverables as part of the DTT planning and clearance process. These changes will only be published by the ITC when it has secured the necessary permissions (these may be granted immediately following Digital-TPG approval on a non-interference/non-protected basis) for the DTT assignment to be implemented. See Annex 1 for details of implementation guidelines for agreeing such notifications.

5. The cost of modifying or replacing transmission equipment must be met by the relevant multiplex licensee(s). Any consequential costs, for example where a change to precision frequency control at a relay station necessitates a change to precision frequency control also at the parent main station (and any intermediate relay stations in the signal chain), must also be met by the relevant licensee(s). The changes must be completed in advance of the commencement of service transmissions from the affecting DTT site.

6. Except for some self-help schemes, the transmission equipment which will need modifying or changing is currently owned and operated either by Crown Castle International (Castle) or NTL. In most cases arrangements will therefore need to be made with the appropriate analogue broadcasters, NTL and/or Castle for the necessary changes to be carried out. In the very small number of cases where self-help schemes might need modifying, arrangements will have to be made directly with the system operator.

   B. Change of Existing Transmission Frequency

7. In those cases where the frequency channel of an existing transmission needs to be changed, the provisions of paragraphs 4-6 above apply. In addition, the relevant multiplex licensee(s) will be required so far as is reasonably practicable to maintain the reception of the affected service, with no reduction in quality, for all viewers who directly receive a service from that transmitter. This will be at no cost to the viewers, and with as little inconvenience caused to them as is reasonably practicable.

8. In order to fulfil this requirement the ITC would expect the following procedure to be adopted:
   • The multiplex licensee(s) should identify the premises which might reasonably be expected to be receiving services from the transmitting station which is to be affected by the planned change of frequency.
   • The multiplex licensee(s) should offer to the occupier of each affected premises the services of an authorised person to carry out the necessary retuning. If the occupant would prefer to do the retuning themselves, then the licensee should offer written instructions on how to carry out the work.
   • The transmission of the services which stand to be affected should commence on the "new" frequency before the switching off of the transmission on the "old" frequency to enable the necessary retuning to be carried out during the overlap period. This period of dual-transmission should last for at least one week, and should be sufficient to allow the necessary retuning to be carried out in advance of the start of DTT broadcasts.
   • If practicable, the transmission using the new frequency should during this overlap period use the same equipment and aerial configuration as that which will be used after the change has been completed. If this is not practicable, then the initial period of the transmissions (using the new frequency) should provide a coverage which is as close as is reasonably practicable to the coverage which will be provided after the change has been completed. In cases where there is potential for mutual interference between the “old” and the “new” frequencies, the dual transmission period may be dispensed with, and retuning should be carried out as quickly as possible after the change-over of frequencies.

9. The "necessary retuning" referred to in paragraph 8 above includes:
• The retuning of any television set in the affected premises which is tuned to be able to receive services from the transmitter whose frequency is to be changed.
• The retuning of any other domestic equipment (eg. VCR) which is tuned to be able to receive services from the transmitter whose frequency is to be changed.
10. This retuning should be carried out in a way which so far as is reasonably practicable results in no reduction in the quality of reception of the affected television and teletext services (and the ease of use of the equipment which is involved) after the frequency change has been made, compared with that which was available before the change. It may be necessary to provide and install a new high quality receiving aerial and/or amplifier in order to meet this requirement. The licensee(s) should use all reasonable endeavours to ensure that the necessary retuning has been completed before the transmission frequency change is made.

11. In cases where the viewer has made additional arrangements to receive services from another transmitter (for example via the installation of an additional aerial) the licensee(s) should make reasonable attempts to support this installation (e.g by supplying a co-axial switch). However, where such reception is by fortuitous means (e.g. via reception from the back of existing antenna) no such requirement will apply.

12. The licensee(s) will remain liable for a period of three months after the frequency change has been made to respond to requests from viewers to carry out the necessary retuning, where this has not been carried out in advance. This three month period must be notified in advance to each premises which might reasonably be expected to be affected by it.

C. Changes in Reception Arrangements Only

13. The trigger point for the application of the requirements of this Code for changes in reception arrangements only is that the picture, sound or teletext component of an existing high priority broadcast service is lost (i.e. reception quality falls below Grade 3 or, where Grade 3 was not previously available, is rendered unusable) as a result of the introduction of DTT transmissions. For these purposes an “existing high priority broadcast service” is a UK terrestrial TV service which was on-air or which had its spectrum plans agreed nationally by 30 March 1997. Included also in this high priority category are any transmitters planned after this date for the purpose of restoring coverage to the 1997 level. The relevance of this date is the status afforded to it by the Government guidance note on priorities for the use of the Broadcasting Spectrum, issued in October 1998 and available from the ITC. For the avoidance of doubt, all BBC 1, BBC 2, ITV, Channel 4/S4C and Channel 5 transmitters which were on air or were approved by TPG before 30 March 1997 are protected by these provisions. TV Restricted Service Licensees (RSLs) and DTT services are not protected under the terms of this Code. For the purposes of this Code households would in general only be served by one regional variation of the above national services, and in Wales they would in general expect to receive the S4C service.

14. The obligations to restore or maintain reception for viewers under this Code extend to direct reception by viewers of any kind, whether the TV viewing can be considered as domestic (e.g. in homes, hospitals or nursing homes) or as non-domestic (e.g. in schools or businesses). The principle in either case is that the direct reception of a current broadcast service is affected. For the avoidance of doubt the licensee is obliged to use reasonable endeavours to restore the service to a level comparable with that which existed prior to the start of the DTT transmissions. Were this is not practicable the licensee should provide the best possible quality of service.

15. The obligations do not apply in general to reception for the purpose of re-distribution, although in cases where reception at the head-end of a community-funded self-help scheme (that is all self-help schemes licensed by the DCMS except those provided by commercial organisations responsible for the coverage deficiency being addressed) is significantly degraded by the digital service the licensee(s) will be required to use reasonable endeavours to restore the service through replacement of input filters or the realignment or replacement of the master antenna.

16. JPP deliverables will outline the predicted extent and location of interference to existing analogue reception where this is expected from a particular DTT site. In these cases, the licensee(s) must use suitable publicity in the vicinity of the predicted area of potential interference to inform viewers of the potential for interference and freephone numbers to contact, in case of interference, in order to arrange a visit to reinstate satisfactory television reception.

17. The licensee(s) must also respond to reports of interference from DTT to the reception of existing broadcast services as defined in Paragraph 13 above.

18. The multiplex licensee should offer to the occupier of each premises that requires a visit the services of an authorised person to carry out the necessary work. If the occupant would prefer to do the work themselves, then the licensee should offer written instructions on how to carry it out. This procedure should be carried out in a way which allows for the remedial work to be completed within 14 days of a request being received for a visit, using all reasonable endeavours.

19. Where the existing principal television service is lost, due to the introduction of DTT services, an alternative service needs to be provided. In such cases the relevant multiplex licensee(s) will be required to use all reasonable endeavours to restore reception, with no reduction in quality and where possible providing the same regional content, for the affected viewers. This will be at no cost to the viewers, and with as little inconvenience caused to them as is reasonably practicable.

    The "necessary work" referred to in paragraph 18 above includes:

• The retuning of any television set in the affected premises to be able to receive services from an alternative transmitter.
• The retuning of any other domestic equipment (eg. VCR) to be able to receive services from an alternative transmitter.
• The realignment or replacement of the existing domestic receiving aerial so as to enable adequate reception of an alternative service. In such cases where the viewer has made additional arrangements to receive services from another transmitter (for example via the installation of an additional antenna) the licensee(s) should make reasonable attempts to support this installation (e.g by supplying a co-axial switch). However, where such reception is by fortuitous means (e.g. via reception from the back of existing antenna) no such requirement will apply.
• In cases where no alternative service can be received by use of the above measures, licensees should consider other possible measures such as replacing access to the analogue service with its digital equivalent (using a digital satellite or terrestrial receiver together with appropriate distribution arrangements if more than one receiver is affected), or the installation of a self-help transmitter where the ongoing costs of operation and maintenance are met by the multiplex licensees concerned.
20. The licensee will remain liable for a period of three months after the start of the affecting digital service to respond to requests from viewers to carry out the necessary work. This three month period must be notified in advance as part of the publicity referred to in paragraph 16 above.

    D. Provision of a New Relay Station

21. Where an JPP deliverable states that it is necessary to provide a new relay station to maintain analogue reception which would otherwise be lost, then this must be implemented to an appropriate specification in accordance with current NTL and Castle practice as agreed by the ITC and BBC. The relay station must be completed in advance of the commencement of the appropriate digital transmissions and must be publicised within the target service area.

22. The procedure for restoring a service to viewers whose reception is adversely affected by the commencement of the appropriate digital broadcasts is the same as that described in paragraphs 18 to 21 above, where in this case the “alternative service” is that provided by the new relay station.

Interference to VCRs, Cable or Satellite Receivers

23. It is possible that in some cases a digital transmission will cause interference to the UHF output of a home VCR, a cable or satellite receiver. There is no obligation on the relevant multiplex licensee to provide a solution to viewers affected in this way, but licensees are required to ensure that information about the proposed changes are made available to local dealers and aerial installers, as well as the relevant satellite and cable operators advance of the changes being implemented.

24. There is no central record of the frequencies to which VCRs or satellite receivers are tuned, but for licensees information Annex 2 gives some estimates provided by Channel 5 of the proportion of such equipment in particular transmission areas which were tuned to different frequencies as part of its retuning programme. Figures for the absolute numbers of homes retuned in each area are given for the channel 35 and 37 retuning.

Test Transmissions

25. Multiplex licensees may, with the ITC’s agreement as to their timing and duration, use test transmissions to assist with identifying and resolving the interference issues covered by this Code. Test transmissions do not count as formal service transmissions for this purpose. At all times, care must be taken to minimise any inconvenience which might be caused to viewers. Where viewers might be affected, advance details of test transmissions should be announced through appropriate publicity.

Annex 1: DTT Frequency Changes: Implementation Guidelines

In order to allow a clear and transparent process for changes in DTT frequency assignments to be agreed and implemented by the ITC and multiplex licensees it is recommended that the following guidelines are to be adopted.

• Stage 1. JPP Deliverables: The Joint Planning Project (JPP) will produce a series of detailed planning documents (deliverables) which will be sent to the digital broadcasters, TV TAP and the transmission operators. These will detail the proposed changes for each site. The deliverable will also make an assessment of any interference arising from the digital services which is predicted to affect existing analogue services together with the proposed remedies (as detailed in the revised Code). They will also identify any additional impact such as changes to current levels of digital coverage or frequency changes which may require viewers and interested parties to be informed.
• Stage 2. Formal Assignment: When the appropriate national and/or international approvals have been granted (please note that clearance may be given following Digital TPG approval on a non-interference/non-protection basis) the ITC will write to each multiplex operator (licensee). For each site this letter will inform each operator of the frequency, power and HRP of the new DTT assignment. The operator will normally be required to write back accepting this assignment and undertaking to inform the ITC at least 8 weeks in advance of their intention to implement this new assignment.
• Stage 3. Public Bulletin: The ITC will maintain on its web site an up to date list of DTT assignments. This will incorporate any changes, as described above, following their formal notification in a Public DTT Update Bulletin which the ITC will issue through a email list. (A draft proposal to this has now been circulated to interested parties for comments).
• Stage 4. It will be the responsibility of the digital broadcasters and their agents to ensure that those affected by these changes are informed in reasonable time according to the provisions of the ITC Code of Practice on Changes to Existing Transmission and Reception Arrangements.

Annex 2: Channel 5 Estimates Of Percentage Of VCRs Retuned To Preset Frequencies




Transmitter	Preset 1	Preset 2	Preset 3
Bilsdale	Channel 39 : 50% 46,000 homes	Channel 40 : 50% 46,000 homes	Channel 32 : 0%
Black Hill	Channel 34 : 60% 315,000 homes	Channel 32 : 30% 158,000 homes	Channel 29 : 10% 53,000 homes
Black Mountain	Channel 39 : 30% 8,700 homes	Channel 35 : 60% 17,400 homes	Channel 29 : 10% 2,900 homes
Cambret Hill	Channel 33 : 20% 5,000 homes	Channel 39 : 80% 21,000 homes	Channel 30 : 0%
Croydon	Channel 40 : 5% 94,000 homes	Channel 41 : 0%	Channel 39 : 95% 1,777,000 homes
Darvel	Channel 39 : 60% 18,000 homes	Channel 31 : 20% 6,000 homes	Channel 38 : 20% 6,000 homes
Emley Moor	Channel 30 : 15% 141,000 homes	Channel 39 : 45% 423,000 homes	Channel 31 : 40% 376,000 homes
Fenton	Channel 39 : 60% 8,400 homes	Channel 38 : 0%	Channel 41 : 40% 5,600 homes
Hannington	Channel 32 : 15% 5,700 homes	Channel 31 : 70% 26,600 homes	Channel 30 : 15% 5,700 homes
Kilvey Hill	Channel 38 : 35% 12,600 homes	Channel 40 : 25% 9,000 homes	Channel 39 : 40% 14,400 homes
Lichfield	Channel 30 : 30% 390,000 homes	Channel 31 : 15% 195,000 homes	Channel 32 : 55% 715,000 homes
Mendip	Channel 31 : 22% 105,000 homes	Channel 34 : 58% 276,000 homes	Channel 39 : 20% 95,000 homes
Presely	Channel 32 : 5% 1,200 homes	Channel 29 : 5% 1,200 homes	Channel 34 : 90% 21,300 homes
Redruth	Channel 31 : 10% 5,000 homes	Channel 29 : 10% 5,000 homes	Channel 34 : 80% 35,000 homes
Ridge Hill	Channel 40 : 10% 4,700 homes	Channel 31 : 0%	Channel 38 : 90% 42,300 homes
Sudbury	Channel 38 : 20% 5,200 homes	Channel 32 : 80% 20,800 homes	Channel 29 : 0%
The Wrekin	Channel 38 : 50% 17,000 homes	Channel 32 : 20% 6,800 homes	Channel 41 : 30% 10,200 homes
Waltham	Channel 39 : 20% 21,000 homes	Channel 32 : 40% 42,000 homes	Channel 30 : 40% 42,000 homes




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