BAND III TRANSMITTING AERIAL FOR THE MOEL-Y-PARC V.U.F. TELEVISION STATION

Transcription

1 RESEARCH DEPARTMENT BAND TRANSMTTNG AERAL FOR THE MOEL-Y-PARC V.U.F. TELEVSON STATON Technological Report No. E-1l7/7 UDC /59 D.\\-. O:"borne, A.\U.l:.E. R.D.C. Thoday, Grad..E.R. E. for Head of Research Department

2 This Report is the property of the British Broadcasting Corporation and may not be reproduced in any form without the written permission of the Corporation. Thn ""pjrt S U)\to tn ~ccord{\n~f' with n.~1. {1{}(,um~!1t PO ~OA6.

3 October, 1966 Research Report No. E-1l7/7 UDC /59 BAND TRANSMTTNG AERAL FOR THE MOEL-Y-PARC V.B.F. TELEVSON STATON NTRODUCTON The Moel-y-Parc relay station came into operation on the 28th October t provides a service to an area including most of the north coast of Wales and to Denbigh, Wrexham and Ruthin to the south. SUMMARY OF NSTALLATON The site is approximately 6-4 km east north-east of Denbigh, grid reference S , height m a.m.s.l Support Structure: General Arrangement: Channel: Aerial: The structure, which supports both BBC and TA aerials, consists of a m (753 ft 6 in.) triangular mast having side dimensions of 2-59 m (8 ft 6 in.) up to the m (563 ft 6 in.) level and 1-98 m (6 ft 6 in.) over the remaining section. One stay lane is_oriented along a bearing of 92 ETN. Provi sion is made for a cantilever u.h.f. aerial. See Fig. 1. Channel 6, with vertical polarization is used. The aerial 1 consistsof four tiers of 1A.dipoles, formed by two panel aerials mounted off each face of a square framework supported between the legs of the mast. The panels are oriented on bearings 20 0, 113, and 285 ETN. A plan view of the panel aerial arrangement is shown in Fig. 2. Each panel consists of two tiers 1'425 m (56-1 in.) apart. Each tier has two vertical la. dipoles with a horizontal separation of 0'798 m (31'4 in.) mounted 0-51 m (20 in.) from a 1-34 m (52-8 in.) by 2'98 m (117 in.) rectangular wire mesh screen. The details of the panels as mounted on the mast are shown in Fig. 3. The panels on bearings 20, 113, and 285 ETN are fed with relative current amplitudes and phases 0'61 /57, 1-0L![', 0-7 /260 and 1'0/180 respectively. The distribution feeder arrangement is shown in Fig. 4. There are independent main feeders to each half aerial. The mean aerial height is m (641 ft) a.g.!. Power: Templet and horizontal radiation pattern (h.r.p.): Gain: Two 2'6 kw transmitters are used. See Fig. 5 and Note Mean intrinsic gain Deduct: loss due to distribution feeder and possible misalignment Mean net gain 6-2 db 0'1 db 6'1 db Deduct: loss in main feeder, type F & G in, Network 10 s s Mean effective gain 1-4 db 0'1 db 1-5 db 4-6 db --

4 2 Programme Source: Note: Programme is provided by s.h.f. link from Great Ormes Head, an intermediate site where the transmissions from Llanddona (Channel 1) are received. The aerial design was carried out by contractors. REFERENCE: 1. Detailed information on the construction and dimensions of the aerial are given on the following drawings held by BBC Transmitter Planning and nstallation Department: General Arrangement of Aerials Schematic Layout and Details of Transformer and Feeders P.LD SA4 RACAL Drawing No. DD SMW

5 ---1~~ cornar on ~.2, of T.N. 22Q 7m (753ft 6in) n 1 ~ provision for u.h.f. aarial 11 \ 2 59m ""( 8ft 6in) Plan of mast from ground to 171 8m (563ft 6in) czvczl 213.7m.l_.T.A.Bandill (701ft) -!:.- --transmitting aarial 195'4m _{_ ( 641ft) BBC Band m --transmitting oarial [>j-~ \ 1 98m '((6ft 6 in) corner on 92 E of T.N. Plan of mast abovcz 171 8m (563ft 6in) czvczl 171 8m (563ft 6in)- 107m (351 tt) 20 E of T.N. 70 7m passiva ra11actor (232ft) - - on E 01 T.N. 200 D E of T.N. 42'06m (138ft) Plan of BBC Band m transmitting aczrial Elczvation Fig.1. General arrangement of aerials on mast

6 N t panal 3 (uppar panal) panal 7 (owar panal) E of T.N. ~ triangular mast J panal 2 (uppar panal) ponal 6 (owar panal) po nal 1 (uppar pa nal) panal 5 (owar panal) panal 4 (uppar panal) - Fig.2. Plan vi<zw of pan<z1 a<zrial arrang<zm<znt

7 t m (6B gin) 1'425m (56 1 in) lowar part of ~ panal 1 /" panal 5 ~ r / ~ t --r ~ '" / ~0.51m\--.. (20 in) i, 1+ 1L Jl ~ ZF :' ~ i\ 1+ r---' Ui r+ ~ lit ~ :~ ' r-- 'r "-.L r t owar part of panal 2 / ~, ---:-1 panal 6 ~ ~~ t------,, _...J Lr /:'1 // /// //1 ////, rrrlr+~~r-~+--~~~, -:.,,,/.--/ v ', ~ / 1,1 r+ H---+-t--t/-r-;-.'H - : ' ', r----' " / " 1'1 r 11 /// < /// - 1,1 11 /// 11" ~V'/ ~ 1'\ // 11// 1 / / 11 r / : 1 / ~~ --c--- r-r-- ~ t~--_l~ ~"" '-...J : ~\ \ \ \ lowar part of panal 3 '\7 datum 195'4 m (641 tt) o.g.l. panal 7,, ~ " 0'75)8m.---. i 1\\ \ s rue ura ~\ \ triangular mast 1\\ \ t t (31'4in) ~~~ _-----~------! \\ \ >~ tj ~..\ Ld Fig.3. Details of panels on mast.

8 , panal 1 panal 2 panal 3 panal 4 "' 1 0 LOo 0 61 L L L i : 99 ~~ ~ ~ ~$ : : 9~ ~~ ~~ ~9 i facing facing facing facing uppar panalsl E of rn. E of tn. E of N. E of T.N. : transformq;r A!, transformar B facing E of T.N. facing 20 E of T.N. facing 285 E of T.N. facing 200 E of T.N. lower panals 1 0 LOo 0 61 L L L2600 L panal S panal G panal 7 panal 8 J BBC Band m transmitting aarial structura. Mountad about 1QS'4m (641ft) datum two son faadczrs of aqual alcctrical langth. / / transmittar (at ground Javel) Fig.4. Sch<zmatic of distribution f<z<zd<zr arrang<zm<znt.

9 Fig.5. T(2mpl(2t and horizontal radiation patt(2rn. VERTCAL POLARZATON Channczl 6 (Vision carriczr Mczan czffczctivcz gain: 4 6dB Transmittczr powczr: 5 2kW Mczan E.R.P.: 15kW MHz Sound carriczr MHz) Maximum pczrmissiblcz E.R.P Minimum dczsirabl,(l E.R.P. Unit ficzld corrczsponds to an E.R.P. of 10kW

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