A Solid Step Forward 

12 March 2018 tbs.pm/65193

From ITV75, published in December 1974 by the Independent Broadcasting Authority

A new uhf transmitter brought on air every week… some 50 a year in 1975, 1976, 1977, 1978 and 1979. This intensive constructional programme will bring the total of uhf transmitting stations to over 400. Some 150 are now in operation, enabling 19 out of every 20 people in the UK to receive 625-line colour or black-and-white pictures.

But the days when a new transmitter would bring 625 lines for the first time to several million people have gone. Only The Wrekin transmitter in 1975 will add some hundreds of thousands. Most of the stations now being built are for under 10,000 people – some only just over 1,000. The big commanding stations with tall masts and high powers are mostly built and working. But, unfortunately, such is the nature of uhf television that there are still many hilly areas where it is difficult if not impossible to receive uhf television.

And wherever one of those ‘gaps’ has more than 1,000 people not receiving the existing stations then you can be sure that the site planners working on the joint iba-bbc programme will have tentatively identified it and marked down the need for a local relay. Unfortunately it is one thing to identify a requirement, another matter to bring the necessary relay on the air.

Power supply and drive unit for a high-power uhf transmitter with the drive unit withdrawn for servicing. Normally the transmitters are run unattended.

Transmitter buildings for a high-power unattended UHF transmitter.

Often the need for a relay is well defined; occasionally one cannot be certain until other nearby stations are transmitting. It’s a question of surveys, computer studies, a patient search for suitable sites where a transmitting aerial would put the signal where it is needed without causing interference to other stations.

The UHF transmitting aerials are normally enclosed in a large cantilever section at the top of the mast.

Often an ideal site does not exist, or if one is found it may not be available or may be subject to lengthy inquiries and negotiations. Local people may not want a transmitting tower at the bottom of their gardens, or may feel it would be an eyesore on the nearby hill. In practice television engineers have developed designs that are as unobtrusive as possible and often avoid the ridge of a hill. But still sometimes it is a matter of carefully weighing questions of environment against the need for a good TV service. And sometimes a TV mast – such as the iba’s unique concrete tower at Emley Moor – actually proves to be a tourist attraction!

But it does take time; and these days nobody sees why they should not have good TV at the turn of a switch. Anything that can be done, once all the necessary permissions have been obtained, to speed up the building of a station is welcome news to public and broadcasters alike.

And one very important step forward was taken by the iba engineers during 1974. For the year saw the first use of a new range of all-solid-state transmitters and a novel form of pre-fabricated steel container units to replace conventional buildings.

‘All-solid-state’, some readers may be saying, ‘that means transistors instead of valves doesn’t it? And surely valves went out years ago in favour of transistors?’

Well, yes and no. Certainly for all iba uhf transmitters the number of ‘valves’ has been very small indeed. But they have always been needed in the final amplifier stages. Nobody has yet been able to develop, for example, the 80,000 watts of TV power needed at the Crystal Palace or even the 1,000 watts used at some local relay stations from transistors.

But real progress is being made and it is now possible to have ‘all-solid-state’ transmitters of 10 watts output (and soon possibly 50 or even 100 watts). This may not seem much power, but it is just what is needed for the small gap-filling stations that cover a radius of perhaps two, three or four miles.

And by going solid-state with carefully designed transmitters, many advantages are possible both for viewers and the broadcasters. Reliability and consistent performance over long periods; stations that can be confidently left unattended, not just for days or weeks but for months. Maybe the flying squad of mobile maintenance engineers will drop in just once or twice a year, after, that is, any ‘teething troubles’ have been eliminated.

And when a fault does occur the design is such that the team will not have to carry out any highly-skilled work on the spot, but just have to pull out and replace a complete subunit which can then be repaired without undue urgency at the base workshops. The whole of the transmitting equipment has been designed so that no longer will it be necessary for these teams to take along elaborate test equipment.

But that is not all. The use of the special ‘container’ building means that it becomes possible for much of the station to be built into the container at iba’s central stores and workshops in north-west London, and then taken on a specially-built vehicle to its final destination, which may be a remote hill in Wales or whenever gap-filling is needed. The vehicle is designed so that the container can be slid off gently on to a prepared site within the base of the aerial tower or immediately alongside. No special cranes or other unloading equipment are needed, and the final connecting up of the station takes just a few days.

The first of these container stations, equipped with all-solid-state transmitters, was installed at Morpeth in the summer of 1974, but already many more of these stations are now in operation.

Of course, this does not mean that a new station now takes only a few days. There is still the aerial tower, often 150 ft high, to build; and often the most time-consuming operation is getting permission to use the site.

But it is a step in the right direction. And the new ‘10-s container stations’ as they are known by the iba engineers, have certainly speeded up the opening of stations. And if by chance you switch on your TV receiver at 9.10 am on any Tuesday morning you’ll receive the special iba service to dealers, listing the new transmitters on test or opening shortly. There have been significantly more names in the lists since iba went container solid-state.

Name Area UHF VHF Reference
Aberdare WW 106,06 SO 034 013
Abergavenny WW 106,18 6,2 SO 244 126
Abertillery WW 106,12 SO 224 023
Abertridwr WW 106,31 ST 123 886
Aldeburgh E 114,02 TM 441 596
Alston NE 109,08 NY 730 478
Angus NS 123 12,1 NO 394 407
Arfon WW 135,03 29,1 SH 476 493
Ashbourne M 102,12 SK 182 460
Aviemore NS 56,2 NH 940 126
Bacup La 103,08 SD 878 224
Bala WW 145,08 29,2 SH 969 375
Balgownie NS 112,04 NJ 927 104
Ballycastle NI 7.2 D 077 423
Bargoed WW 106,08 SO 145 010
Bassenthwaite B 137,07 NY 207 305
Bath WW 110,02 6.1 ST 769 654
Beacon Hill SW 136 SX 857 619
Bedlinog WW 106,43 SO 102 005
Belmont Y 120 20 TF 218 836
Bethesda WW 118 04 SH 613 663
Betws-y-Coed WW 118,01 SH 825 582
Biggar CS 105,03 NT 016 325
Bilsdale NE 116 SE 553 962
Birch Vale La 103,11 SK 028 861
Black Hill CS 105 5 NS 828 647
Black Mountain NI 107,07 7 J 278 727
Blaenavon WW 106,17 SO 277 063
Blaen-Plwyf WW 135 SN 569 756
Blaina WW 106,14 SO 196 083
Blair Atholl NS 123,07 NN 894 658
Bluebell Hill Ln 158 TQ 757 613
Bolehill M 102,13 SK 295 552
Brecon WW 106,49 6.3 SO 054 287
Bridport SW 132,06 SY 450 920
Brierley Hill M 102,03 SO 916 856
Brighton S 108,05 TQ 329 045
Bristol Ilchester Crescent WW 110,08 ST 577 700
Bristol Kings Weston Hill WW 110,07 ST 547 775
Bromsgrove M 102,06 SO 948 730
Broucher Mountain NI 151 H 350 527
Burnhope NE 9 NZ 184 474
Buxton M 102,24 SK 060 753
Caldbeck B 137 37 NY 299 425
Calver Peak Y 104,18 SK 232 743
Campbeltown CS 152,06 NR 707 192
Caradon Hill SW 131 31 SX 273 707
Carmel WW 119 SN 576 153
Carnmoney Hill NI 107,02 J 336 829
Catton Beacon NE 109,09 NY 822 591
Cerne Abbas WW 110,29 ST 645 013
Chartham S 113,05 TR 103 561
Chatton NE 155 NU 105 264
Chesterfield Y 104,05 SK 383 764
Chillerton Down S 8 SZ 475 835
Cirencester WW 110,19 SP 005 058
Clyro WW 106,51 SO 204 432
Congleton La 103,27 SJ 865 619
Coniston La 103,45 SD 327 966
Conway WW 118,03 SH 781 765
Cop Hill Y 104,11 SE 058 138
Craigkelly CS 147 NT 233 872
Crieff NS 123,02 NN 814 200
Croeserw WW 106,27 SS 858 952
Croydon Ln 1 TQ 332 696
Crystal Palace Ln 101 TQ 339 712
Cwmafon WW 106,24 SS 798 936
Darvel CS 152 NS 557 341
Darwen La 103,01 SD 708 223
Deri WW 106,57 SD 121 022
Divis NI 107 J 286 750
Dover S 113 13 TR 274 397
Dunkeld NS 123,11 ND 046 415
Durris NS 112 12 NO 763 899
Ebbw Vale WW 106,13 SO 159 088
Eitshal (Lewis) NS 154,00 NB 306 302
Emley Moor y 104 4 SE 222 128
Eyemouth B 161,01 NT 947 599
Fenham NE 109,03 NZ 216 648
Fenton Ai 102,11 SJ 902 450
Ferndale WW 106,19 ST 006 970
Ffestiniog WW 29,3 SH 709 391
Findon S 108,07 TQ 120 072
Fremont Point Ch 28 49° 15’N, 2° 8’W
Galashiels B 161,02 NT 507 360
Gartly Moor NS 112,02 NJ 547 326
Gilfach Goch WW 106,28 SS 982 890
Girvan CS 152,05 NX 211 981
Glossop La 103,13 SK 027 953
Great Missenden Ln 101,14 SP 905 006
Guildford Ln 101,01 SU 974 486
Gunnislake SW 131,04 SX 440 720
Halifax Y 104,06 SE 103 242
Haltwhistle B 137,05 NY 674 628
Hannington S 126 SU 527 568
Haslingden La 103,03 SD 795 236
Hastings S 139,02 TQ 807 100
Hawick B 161,03 NT 510 148
Heathfield S 139 TQ 566 220
Hebden Bridge Y 104,09 SD 988 267
Hemel Hempstead Ln 101,05 TL 088 045
Henley-on-Thames Ln 101,10 SU 780 822
Hertford Ln 101,02 TL 320 137
Heyshaw Y 104,44 SE 170 631
High Wycombe Ln 101,07 SU 856 942
Huntshaw Cross SW 138 32,1 SS 527 220
Icomb Hill M 102,19 SP 202 229
Idle Y 104,13 SE 164 374
Innerleithen B 161,08 NT 325 368
Keelylang Hill (Orkney) NS 134,00 HY 378 102
Keighley y 104,07 SE 069 444
Kendal La 103,36 SD 540 912
Keswick B 137,02 NY 279 224
Kidderminster M 102,02 SO 808 739
Kilkeel NI 107,03 J 281 180
Killearn CS 105,06 NS 483 848
Killowen Mountain NI 107,30 J 207 174
Kilmacolm CS 105,01 NS 343 691
Kilvey Hill WW 106,01 SS 672 940
Kirkconnel CS 152,02 NS 746 150
Knock More NS 153 NJ 321 497
Ladder Hill La 103,09 SK 027 789
Lancaster La 103,35 SD 490 662
Langholm B 137,15 NY 358 831
Lark Stoke Ai 102,08 SP 187 426
Larne NI 107,01 D 395 037
Leek M 102,10 SJ 999 561
Lethanhill CS 152,04 5,3 NS 438 106
Lichfield M 2 SK 164 043
Limavady NI 130 C 711 296
Littleborough La 103,22 SD 950 166
Llanddona WW 118 SH 583 810
Llandovery WW 29,4 SN 831 405
Llandrindod Wells WW 119,04 29,5 SO 019 635
Llanelli WW 119,01 SN 510 023
Llangeinor WW 106,22 SS 905 886
Llanhilleth WW 106,26 SO 213 004
Londonderry NI 130,01 C 404 175
Luton E 101,08 TL 081 210
Maesteg WW 106,04 SS 841 913
Malvern M 102,07 SO 774 464
Marlborough S 110,24 SU 209 688
Membury M 2,1 SU 307 763
Mendip WW 110 ST 563 488
Mendlesham E 14 TM 122 641
Merthyr Tydfil WW 106,07 SO 057 066
Midhurst S 125 SU 912 250
Milburn Muir CS 152,10 NS 378 796
Moel-y-Parc WW 145 45 SJ 123 701
Morpeth NE 109,10 NZ 218 864
Mounteagle NS 56 NH 639 580
Mynydd Bach WW 106,42 ST 168 925
Mynydd Machen WW 106,03 ST 223 900
Newcastle NI 107,05 J 362 303
Newhaven S 139,01 8.1 TQ 435 006
Newry Nl 107,04 J 091 221
Newton NE 109,02 NZ 035 653
North Oldham La 103,25 SD 929 060
Nottingham Ai 102,23 SK 503 435
Oakenhead La 103,31 SD 806 234
Ogmore Vale WW 106,30 SS 929 894
Oliver’s Mount Y 104,38 TA 040 869
Oxenhope Y 104,17 SE 028 338
Oxford M 117 SP 567 105
Peebles B 161,07 NT 228 418
Penaligon Downs SW 131,10 SX 027 683
Pendle Forest La 103,02 SD 825 384
Penicuik CS 147,01 NT 252 590
Perth NS 123,01 NO 108 212
Peterhead NS 112,01 NK 112 453
Pitlochry NS 123,05 NN 923 565
Plympton (Plymouth) SW 131,05 SX 531 555
Pontardawe WW 106,56 SN 731 037
Pontop Pike NE 109 NZ 148 526
Pontypool WW 106,15 ST 284 990
Pontypridd WW 106,05 ST 085 905
Porth WW 106,20 ST 029 919
Presely WW 129 29 SN 172 306
Redruth SW 141 SW 690 395
Reigate Ln 101,03 TQ 256 521
Rhondda WW 106,02 SS 989 939
Rhymney WW 106,09 SO 127 042
Richmond Hill B 37,2 SC 335 748
Ridge Hill M 149 2,2 SO 630 333
Ripponden Y 104,10 SE 043 189
Rosehearty NS 112,03 NJ 933 663
Rosemarkie NS 156 NH 762 623
Rosneath CS 152,11 5.1 NS 258 811
Rothesay CS 105,11 5.2 NS 125 690
Rowridge S 108 SZ 447 865
Rumster Forest NS 148 56,1 ND 197 385
Saddleworth La 103,06 SD 987 050
St. Austell SW 131,01 SX 008 536
St. Hilary WW 6 ST 026 741
St. Thomas (Exeter) SW 132,01 SX 898 922
Salisbury S 108,01 SU 136 285
Sandy Heath E 124 14.1 TL 204 494
Scarborough Y 4.1 TA 009 880
Scilly Isles SW 141,01 SV 911 124
Sedbergh La 103,15 SD 607 879
Selkirk B 161 37,1 NT 500 294
Shatton Edge Y 104,08 SK 194 814
Sheffield Y 104,03 4,2 SK 324 870
Skipton Y 104,04 SD 909 517
South Knapdale CS 105,02 NR 837 748
Stanton Moor M 102,09 SK 246 637
Stockland Hill SW 132 32 ST 222 014
Strabane NI 151,01 7,1 H 393 947
Stroud WW 110,18 SO 836 077
Sudbury E 115 TL 912 376
Sutton Coldfield M 102 SK 113 003
Tacolneston E 114 TM 131 958
Taff’s Well WW 106,29 ST 123 848
Tay Bridge NS 123,08 NO 430 284
The Wrekin M 121 SJ 629 081
Tideswell Moor Y 104,22 SK 149 780
Todmorden La 103,05 SD 958 241
Tonypandy WW 106,35 SS 986 924
Trawden La 103,18 SD 909 378
Treharris WW 106,23 ST 103 964
Tullich NS 112,05 NO 379 984
Tunbridge Welli Ln 101,04 TQ 607 440
Ventnor S 108,03 SZ 567 783
Walsden La 103,20 SD 927 235
Waltham M 111 SK 809 233
Weardale NE 109,06 NZ 025 384
Wenvoe WW 106 ST 110 742
West Linton CS 147,03 NT 164 508
West Runton E 114,01 TG 186 412
Westwood WW 110,03 ST 817 597
Weymouth SW 132,08 SY 663 778
Whalley La 103,19 SD 729 352
Wharfedale Y 104,01 SE 198 485
Whitby NE 116,01 NZ 903 113
Whitehaven B 137,01 37,3 NX 992 123
Whitewell La 103,32 SD 833 245
Whitworth La 103,12 SD 886 202
Windermere La 103,38 SD 383 980
Winterborne Stickland S 108,10 ST 838 051
Winter Hill La 103 3 SD 660 144
Wooburn Ln 101,09 SU 916 873
Woolwich Ln 101,06 TQ 460 794

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