VHF Broadcast Re-planning
This brief study reviewed the potential for further sound broadcasting services to be accommodated in the VHF/FM band (Band II). Its intention was to determine the likelihood of frequencies being available for the introduction of further services within the UK, using London and Leeds as case studies. It is essential to note that the study did not undertake the full frequency planning exercise that will be required to confirm the availability or otherwise of potential new frequencies; it was however the necessary precursor to such work.
The study considered the provision of three categories of service for London and Leeds within the present usage of Band II spectrum:
The report concluded that there is scope to introduce a number of services with a radius up to 5 km with little or no impact on existing services. However, it is unlikely that new larger-scale services could be introduced under current planning criteria in the areas examined, without impacting to a greater or lesser extent on existing services, notably by way of the need for frequency changes and/or the loss of coverage. This study sought to determine the approximate magnitude of the penalty to be paid for the introduction of new services in each area.
The study suggests that a single London-wide service might be planned at a cost of either reducing the population coverage of two existing stations in the Home Counties by 25% or by reducing the coverage of a BBC National service by 100,000 listeners.
As another extreme, the study assumed the need to plan for an arbitrary number of nine new London-wide service frequencies. The implications of this would be a cost of loss of services to over 4 million listeners in stations in and around London (including the closure of some services altogether) and the need for frequency changes by around 28 existing services.
To illustrate the possibilities of planning for smaller scale services, the study considered a number of arbitrarily-chosen new local low powered stations within London and concluded that a number of such stations with a service radius of 3‑5 km, could be introduced with little or no impact on existing stations.
It appears possible to accommodate a new Leeds-wide service from two transmitters with a coverage of around 1.5 million listeners by moving the frequencies of three existing stations.
In addition, other moves of existing stations in the close vicinity could deliver a further two stations covering Bradford and one service covering Leeds. However, this leaves a trail of knock-on effects to stations in the wider areas to all but offset the benefits.
In addition it is possible to introduce smaller scale (3‑5 km) stations in towns in the area, particularly those shielded in valleys, without any significant impact on existing services, most easily using frequencies in the Classic FM and BBC National bands. To validate this, the study examined the feasibility of introducing stations in Leeds and Bradford. A station in Leeds, for example, could be planned to give coverage to an audience of around 110,000 listeners.
The study also endorsed the efficiency with which the spectrum is currently planned by the Radio Authority and the BBC bearing in mind their differing requirements and the obligations they face under the Broadcasting Acts and the BBC Charter.
The study also examined some other areas to consider in order to increase the productivity of the spectrum, including relaxing current planning criteria and standards and making different assumptions about receiver performance etc. The study concluded that:
Copyright Acknowledgement Notice
Maps in this document are reproduced from 1:250000 Scale Colour Raster (2nd June 2000) Ordnance Survey mapping with permission from Ordnance Survey on behalf of the Controller of HMSO, © Crown Copyright.
Coverage predictions in this document are based on Land-Form PANORAMA (2nd June 2000) Ordnance Survey mapping with permission from Ordnance Survey on behalf of the Controller of HMSO, © Crown Copyright.
Population counts are derived from 1991 Usually Resident Population data at Enumeration District level using MapInfo Enhanced Centroids with permission of MapInfo and the Office of National Statistics, © MapInfo, © Crown Copyright.