The service area of the Llanddona television transmitter

Transcription

1 . RESEARCH DEPARTMENT The service area of the Llanddona television transmitter R'EPORT No. K 165 1H3fs8 THE BRITISH BROADCASTING CORPORATION ENGINEERING DIVISION,

2 RESEARCH DEPARTMENT THE SERVICE AREA OF THE LLANDDONA TELEVISION TRANSMITTER Report No. K-165 (1963/50 ) H.T. Madoc-Jones J.A. 'Carter ;l')"9.c~~~ -. (W. Proctor Wilson)

3 This Report is the property of the British Broadcast.lug Corporation and aa7 Dot be reproduced in any form without the written perals$lod ot tbe Corporation.

4 Report No" K-165 THE SERVICE AREA OF THE LLANDDONA TELEVISION TRANSMITTER Section Title Page SUBJECT..., L SUMMARIZED DESCRIPTION OF TRANSMITTER 1 2. SURVEY RESULTS., 1 3. COMMENTS ON SERVICE 3 APPENDIX., ,

5 2 MapT LLANDDONA Band I Channel 1 (Measureg) SITE HEIGHT: 460 ft (140 m) a.m. s.1. AERIAL: TWO TIERS OF VERTICAL DIPOLES -& N AERIAL HEIGHT: 256 ft (78 m) a. g.1. E.R.P. : kw RESEARCH DEPARTMENT POLARIZATION: VERTICAL H.R.P. TECHNICAL MEMORANDUM NO. E-I076 NO'rnS: 1. The contours represent the field strength in decibels (db) relative to lp.v/ m at 30 ft (9 Lm) above ~round exceeded at 50% 0 f recei ving si tes in a gi ven locali ty. The value exceeded at 90% of recei v- 1ng sites may be as much as 10 db below the value indicated by the contours, particularly in hilly and buil t-up areas. 2. -x--~ Limit of service area free from perceptible co-channel interference from all U.K. cochannel transmitters for 90% of the time based on a protection ratio of 45 db with a reduction of 10 db for cross polarization and 10 db for frequency offsets, allowance being made for receiving aerial directivity.

6 3 3. COMMENTS ON SERVICE Holme Moss provides a good service to the north coast of Wales to a point as far west as Colwyn Bay, while Blaen-Plwyf serves that part of the Lleyn Peninsula which has a southern aspect. The Llanddona transmitter serves the coastal strip of North Wales from near the extremity of the Peninsula to, and including, Llandudno and most of Anglesey. Co-channel interference is severe. A field strength of 57 d8(~v/m) is protected for 90% of the time; hence the service in the south-western half of the Lleyn Peninsula and the west of Anglesey will be poor from time to time. Holyhead will in due course be served by its own relay station. The service in North Wales is severely restricted by the mountainous terrain. Neither 8etws-y-Coed nor Llanrwst is served.

7 4 APPENDIX Town Field Strength (db(~v/m» for Stated Percentage Locations l<m 50% 90% * Aberdaron Abererch Aberffraw Abersoch *Amlwch * Bangor *Beaumaris Beddgelert Benllech Bethel and Saron Bethel *Bethesda Bodedern Bodfordd Bont-Newydd Botwnnog Bryngwran Brynkir Bryn-Siencyn Bryn-yr-Efail Cae-Athraw Caellwyn-Grydd Caergeiliog * Caernarvon Carmel Cemaes Bay Otwilog * Clynnog-Fawr *Colwyn Bay *Conway Cwm-y-Glo * Deganwy Deiniolen Dinorwic Dwygyfylchi Dwyran Edern Efail Newydd *Popu1ation over 1,000

8 5 Town Field Strength (db(~v/m» for Stated Percentage Locations 10% 50% 90% Fachwen Four Crosses Four Mile Bridge Gadlys Gaerwen Gallt-y-Foel Garn Dolbenmaen Gerlan and Braich Melyn Glanrhyd Groeslon Gwalchmai Gyrn <loch Hendre Hermon *Holyhead Llanaelhaiarn Llanbedrgoch Llanbedrog *Llanberis Llanddeusan t * Llandudno Llandudno Junction Llanengan Llanerchymedd Llanfachraeth Llanfaelog and Bryndu Llanfaethlu *Llanfairfechan Llanfair P.G. n Llanfechell 52 Llanfwrog Llanga o Llangefni Llangian Llanllechid and Caellwyn-Grydd Llanllyfni Llannor Llanrhos Llanrug Llansaintfrain-Glan Conway Llithfaen *Popu1ation over 1,000

9 6 ALG Town Field Strength (dbguv/m» for Stated Percentage Locations 10% 50% 90% *Menai Bridge Mochdre Moelfre Morfa Nevin NantlIe *Nevin Newborough Pen-Isor-Waen *Penmaen-Mawr Penrhyn-Bay Pen rhyn-side Pentraeth Pentre Berw Pen-y-Ffridd Pen-y-Groes Pen-y-Groeslon Penysarn Pi styli Pont-Llyfni Port Dinorwic *PwlIheli Rhiwlas Rhos-Gadfan Rhos-Meirch Rhosneigr Rhostryfan Rhosybol Rhyd-lliu Rhyd-Wyn Rhy-y-Clafdy Sarn Tal-y-Sarn Trearddur Bay Treffynon Tregarth Trevor T~dweiliog Tywyn Valley Waunfawr *Population over 1,000 Printed by B.B.C. Research Department, Kingswood Warren, Tadworth, Surrey