BBC Freedom Of Information - transmitter radiation patterns
It has always been a great disappointment that the full radiation patterns for transmitters are not published by the transmitter companies.
A few weeks ago, I used the Freedom of Information Act to request this information from the BBC.
And, very kindly, they have provided it all!
This will mean, when I have processed the data, to be able to provide improved prediction maps and other facilities on the site.
I'll be posting more about what this data means in the next week. However, if you want to look at the raw information yourself, it can be downloaded here as a ZIP file (10.2MB).
- There is one file for each multiplex on each transmitter (3713 patterns in total), although not all sites are guaranteed to be built, and other sites might be required to be added later. Note that the two-digit number in the file name is the frequency channel.
- The attached spreadsheet is an index which lists each transmitter, multiplex, and filename.
- The antenna pattern files all end in a .plt file extension, but these are all plain text files that can be read by any text editor. However, they are in unix format, not MSDOS format, so they use only line feed instead of line feed and carriage return at the end of each line. If your text editor does not support this, there are plenty of free unix-to-MSDOS conversion utilities that you can download.
- There are two types of PLT files 2-dimensional and 3-dimensional.
- The 2-dimensional patterns contain a line near the start that says, for example, "HORIZONTAL 360" meaning that this file contains a horizontal radiation pattern (ie a normal top-down view of the antenna pattern not to be confused with the antenna polarisation) with 360 measurement points. This is followed by 360 measurements (1 degree apart) in dB below maximum erp. Not all 2D files have a 1 degree resolution some may be 5 degrees or 10 degrees.
- The 3-dimensional patterns (recognisable by their much larger file size) are more complex. These contain a line for example like "PATTERN 360 101". This means the antenna pattern has 360 horizontal measurements around (1 degree resolution) and for each of those there are 101 sets of results at different angles of elevation from the horizontal (ie. the vertical radiation pattern at each of the 360 degrees). The next line of the file lists those 101 angles which might typically run from -5 degrees (above the horizontal) to +20 degrees (below the horizontal) in 0.25 degree steps. For each of these 360 x 101 points is a measurement in dB below maximum erp. The number of horizontal points is not always 360 (but mostly is) and may be 5 degree or 10 degree resolution instead, and the number of vertical elevations recorded will vary a lot, and will not always be at the same resolution (eg. another possibility might be 76 different elevations between 0 and 15 degrees below the horizontal in 0.2 degree steps). The steps are not guaranteed to be evenly spaced in all cases, so you must read the top line of elevation angles in order to interpret the data correctly.
- A small number of antennas (27) do not yet have a plt file assigned to them. For these, in the spreadsheet, there is a column which gives a simple 10 degree resolution pattern as a 72 character string (36 two-digit values for the angles between 0 and 350 degrees).
- This is similar to the above (520 patterns in total) except that the antenna pattern files all end in a .rpd file extension.
- Within the RPD file is information about the transmitter name and frequency channel, and the filename consists of the transmitter number (5 digits) followed by the 2 digit frequency channel. The included spreadsheet includes a transmitter number to name conversion for these files.
- The format of the antenna pattern data is similar to the PLT files, giving the number of points around the pattern, and the number of elevations for which patterns exist, and the range of those elevations. Eg 72 11 0.00-10.00 means 72 points around (5 degree resolution, starting at zero degrees), and 11 elevations between 0 and 10 degrees (below horizontal), ie 1 degree apart. Unlike PLT files, the RPD elevation angles are always equally spaced.
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Mike Dimmick: Thanks for doing all of those.
I have now - after some considerable copy and pasting - linked the images into the transmitter pages for these 853 transmitters:
Aberbeeg, Abercraf, Abercynon, Aberdare, Aberfoyle, Abergavenny, Abergwynfi, Abertillery, Abertridwr, Aberystwyth, Abington, Acharacle, Addingham, Afon Dyfi, Ainstable, Aislaby, Aldbourne, Alexandra Palace, Allenheads, Allesley Park, Alltwen, Alston, Alton, Alverton, Ambergate, Andoversford, Ardentinny, Ardintoul, Ardnadam, Arisaig, Armitage Bridge, Arrochar, Ascott under Wychwood, Ashburton, Ashford in the Water, Assendon, Attadale, Auchmore Wood, Auchtermuchty, Austwick, Avening, Aveton Gifford, Aviemore, Avoch, Ayr South, Backbarrow, Backwell, Bacup, Badachro, Bainbridge, Bala, Balblair Wood, Balgownie, Ballachulish, Ballintoy, Ballycastle, Balmullo, Balnaguard, Baltasound, Bampton, Banbridge, Banff, Bangor, Bargoed, Barnstaple, Bassenthwaite, Bath, Batley, Beaminster, Beddgelert, Bedlinog, Beecroft Hill, Bellair, Bellanoch, Bellingham, Belper, Ben Tongue, Berwick, Bethesda, Bethesda North, Betws-yn-Rhos, Bidston, Biggar, Biggin Hill, Birch Vale, Birchover, Bishops Stortford, Blackburn, Blackburn In Rotherham, Blackmill, Blaenau Gwent, Blaenavon, Blaenllechau, Blaina, Blair Atholl, Blakeney, Blaydon Burn, Bleach Green VP, Boddam, Bolehill, Bollington, Bonchester Bridge, Borve, Boscastle, Bossiney, Bovey Tracey, Bovington, Bowmore, Box, Bradford West, Braemar, Brailes, Bramford, Branscombe, Braunton, Brechfa, Brechin, Brecon, Bressay, Bretch Hill, Bridge of Allan, Bridgnorth, Brierley Hill, Brinscall, Bristol Barton House, Bristol Ilchester Crescent, Bristol Kings Weston, Bristol Montpelier, Bristol Warmley, Briton Ferry, Broadbottom, Brockwell, Broneirion, Bronnant, Bronwydd Arms, Brook Bottom, Broughton, Bruernish, Brushford, Bruton, Buckfastleigh, Buckna, Bucknell, Builth Wells, Burbage, Burgar Hill VP, Burrington, Burry Port, Bury St Edmunds, Buxton, Byrness, Caergybi, Callander, Calne, Calver Peak, Camperdown, Cane Hill, Canford Heath, Cannongate HP, Carhampton, Carie, Carnmoney Hill, Carno, Carradale, Cartmel, Castle Caereinion, Castleton, Caterham, Cathcart, Catrine, Catton Beacon, Cefn Mawr A, Cerrigydrudion, Chagford, Chaigley, Chalford, Chalford Vale, Charlbury, Chatburn, Chatham Town, Cheadle, Chepping Wycombe, Chepstow, Cheselbourne, Chesham, Chesterfield, Chideock VP, Chilfrome, Chingford, Chinley, Chisbury, Chiseldon, Chitterne, Chudleigh, Cilfrew, Cilycwm, Cirencester, Claonaig, Clearwell, Cleckheaton, Clovenfords, Clun, Clydach, Clyro, Coalbrookdale, Coed Derw, Coleford, Collafirth Hill, Compton, Congleton, Conisbrough, Coniston, Conlig, Cop Hill, Copley, Cornholme, Corris, Corsham, Corwen, Cow Hill, Cowling, Cragg Vale, Craig Cefn Parc, Craigellachie, Creake, Crediton, Creetown, Crewkerne, Crickhowell, Crieff, Crockerton, Croeserw VP, Cromarty, Crosby Ravensworth, Crosthwaite, Croyde, Croydon (Old Town), Crucorney, Crumlin, Cullingworth, Culm Valley, Cumbernauld Village, Cupar, Cushendall, Cushendun, Cwm Ffrwd-Oer, Cwm Twrch, Cwmafon, Cwmaman, Cwmfelinfach, Cwmgors, Cwrtnewydd, Cyffylliog, Cynwyl Elfed, Daliburgh, Dallington Park, Dalmally, Darley Dale, Dartmouth, Deanston, Deiniolen, Delph, Dentdale, Derby, Deri, Dog Hill, Dolgellau, Dollar, Dolwyddelan, Donhead, Dorking, Dowlais, Draperstown, Dromore, Dronfield, Duffryn, Dumfries South, Duncraig, Dunkeld, Dunkeld Town, Dunsford, Dunure, Durham, Durness, Dursley, Dychliemore Link, Eardiston, Earl Sterndale, Easdale, East Grinstead, Easter Compton, Eastwood, Ebbw Vale, Ebbw Vale South, Edale, Edginswell, Edmonton, Efail Fach, Elland, Ellon, Elton, Erwood, Esh, Eskdale Green, Eston Nab, Ewyas Harold, Exford, Eyemouth, Falstone, Far Highfield, Farleigh, Farningham, Faversham, Felling, Fenham, Ferndale, Fernhill, Ferryside, Fetlar, Finchley, Fintry, Fitful Head, Fiunary, Fodderty, Forest Row, Fort Augustus, Fowey, Foxdale (IoM), Frome, Galashiels, Garelochhead, Garth Hill VP, Gartley Moor, Gellifendigaid, Gib Heath, Gigha Island, Gilfach, Glasgow West Central, Glen Convinth, Glen Urquhart, Glenariff, Glencoyne (Glenridding Link), Glenluce, Glenridding, Glespin, Glossop, Glyn Ceiriog, Glyncorrwg, Glyndyfrdwy, Glynn, Gorleston on Sea, Gortnageeragh, Gourdon, Grandtully, Grangemouth, Grantown Link, Grasmere, Grassington, Gravelly Hill, Gravesend, Great Missenden, Great Torrington, Greenwich, Greystoke, Grimsby, Grinton Lodge, Gronant, Guisborough, Guiting Power, Gunnislake, Haddington, Haden Hill, Hagg Wood, Halesowen, Halifax, Haltwhistle, Halwell, Ham Street, Hammersmith, Hampstead Heath, Hamstead, Harbertonford, Harborne, Hartington, Hasland, Haslemere, Haughton Green, Hawick, Hawkshead, Haydon Bridge, Haywards Heath, Hazler Hill, Headingley, Hebden Bridge, Hedleyhope, Hele, Helston, Hemdean, Hemel Hempstead, Hemel Hempstead Town, Henley-on-Thames, Hereford, Hertford, Heyshaw, High Keil, High Wycombe, Holmfield, Holmfirth, Holmhead, Honiton, Hope, Hope under Dinmore, Horndean, Hughenden, Humshaugh, Hunmanby, Hurstbourne Tarrant, Hutton, Icomb Hill, Idle, Innerleithen, Inverarish, Inverness, Ipstones Edge, Ireshopeburn, Ironbridge, Jedburgh, Keelylang Hill, Keighley, Kelvindale, Kendal Fell, Kenilworth, Kenley, Kenmore, Kensal Town, Kerry, Keswick, Kettlewell, Kewstoke, Kidderminster, Kielder, Killearn, Killin, Kilmacolm, Kilve, Kimpton, Kings Lynn, Kingskerswell, Kington, Kingussie, Kinlochbervie, Kinlochleven, Kinross, Kintraw, Kinver, Kirkby Stephen, Kirkconnel, Kirkcudbright, Kirkfieldbank, Kirkmichael, Knockmore, Knucklas, Kylerhea, Ladder Hill, Lairg, Lamberhurst, Lambourn, Langholm, Langley, Largs, Larne, Lauder, Lea Bridge, Leadhills, Leamington Spa, Lees, Leicester, Limber Hill, Lincoln Central, Lindores, Linnet Valley, Little Eaton, Little Walsingham, Littleborough, Liverton, Llanarmon-yn-Ial, Llanbrynmair, Llandderfel, Llanddulas, Llandinam, Llandysul, Llanelli, Llanengan, Llanfach, Llanfoist, Llanfyllin, Llangadfan, Llangeinor, Llangernyw, Llangollen, Llangurig, Llangybi, Llangynog, Llanharan, Llanhilleth, Llanidloes, Llanrhaeadr ym Mochnant, Llansawel, Llanuwchllyn, Llanwrtyd Wells, Llwyn Onn, Llyswen, Loch Feochan, Lochearnhead, Lochgoilhead, Lochinver, Lochmaddy, Lochwinnoch, Long Compton, Longwood Edge, Lorton, Lostwithiel, Lowther Valley, Luddenden, Ludlow, Lumphanan, Luton, Lydbrook, Lydgate, Macclesfield, Machen Upper, Machynlleth, Maentwrog, Maesteg, Mallaig, Manchester Hulme, Marlborough, Marlow Bottom, Marystow, Matlock, Melling VP, Melvich, Merthyr Tydfil, Methven, Micklefield, Mickleham, Middleton, Millbrook VP, Millburn Muir, Millhouse Green, Millom Park, Millport, Millthrop, Minnigaff, Mochdre, Modbury, Moel y Sant, Moffat, Moneymore, Monksilver, Monmouth, Morpeth, Moss Bank, Mottram in Longdendale, Mountfield, Muddiford, Muirkirk, Mynydd Bach, Mynydd Emroch, Mynydd Machen, Nailsworth, Nant Y Moel, Nantyglo, Neath Abbey, Ness Of Lewis, Netherton Braes, New Addington, New Barnet, New Cumnock, New Galloway, New Radnor, Newbattle, Newchurch, Newnham, Newton, Newton Abbot VP, Newtownards, Norden, North Bovey, North Hessary Tor, North Oldham, Norwich Central, Nottingham, Oakamoor, Oakeley Mynd, Oakenhead, Oban, Ogbourne St George, Ogmore Vale, Okehampton, Old Coulsdon, Onich, Orpington, Orton, Otford, Oughtibridge, Over Biddulph, Over Norton, Ovingdean, Oxenhope, Parbold, Parkend, Parwich, Peebles, Pembroke Dock, Pen-y-Banc, Pencader, Penderyn, Pendle Forest, Penicuik, Penifiler, Pennar, Pennorth, Pennsylvania, Penny Bridge, Penrhiwceiber, Penrhyn-Coch, Perry Beeches, Perth, Peterchurch, Peterhead, Peterlee, Pierowall, Pillowell HP, Pitlochry, Plymouth North Rd VP, Plymouth Weston Mill, Pontardawe, Pontfadog, Pontypool, Pontypridd, Poolewe, Pooley Bridge, Poplar, Porlock, Portbury, Porth, Porthleven, Portishead, Portreath, Portwood, Poulner, Prestatyn, Prestbury, Presteigne, Primrose Hill, Pwll-glas, Queslett, Rampisham, Ramsbottom, Ramsey (IoM), Ravenscar, Ravenscraig VP, Ravenstonedale, Redbrook, Redcliff Bay, Redditch, Repton, Rhayader, Rheola, Rhondda Fach, Rhymney, Ribblesdale, Ripponden, Risca, Roadwater, Romaldkirk, Romiley, Rookhope, Roose, Rosedale Abbey, Rosehearty, Rosneath, Ross on Wye, Rothbury, Rothesay Town, Rugeley, Rumster Forest, Saddleworth, Scalloway, Scoval, Seagry Court, Seaham, Sedbergh, Sedlescombe, Selkirk, Sennybridge, Shatton Edge, Sheffield, Shotleyfield, Shrewton, Singleton, Siston, Skinningrove, Skipton, Skipton Town, Skirmett, Slad, Somersham, Sorn, South Brent VP, South Maesteg, South Tredegar, Southway, Spean Bridge, St Albans, St Anthony-in-Roseland, St Bees, St Briavels, St Fillans, St Marks, St Neot, Staffin, Staithes, Stamford, Stanton Moor, Stavely In Cartmel, Stockport, Stocksbridge, Stow, Strachur, Strathallan, Strathblane, Strathyre, Strathyre Link, Strontian, Stroud, Sunderland, Sutton in Craven, Sutton Row, Swimbridge, Swinster, Taffs Well, Talley, Tarbert, Tarbert (Harris), Tavistock, Tay Bridge, Taynuilt, Tayvallich, Tedburn St Mary, Tenbury Wells, Tenby, The Bournes, Thetford, Thornhill, Threlkeld, Thurso, Tideswell Moor, Tidworth, Tighnabruaich, Till Valley, Tillicoultry, Tintern, Tiverton, Todmorden, Tomatin, Tomich, Tomich Link, Tomintoul, Ton Pentre, Tonypandy, Tonyrefail, Totley Rise, Totnes, Trawden, Trebanog, Trecastle, Trefechan, Tregaron, Tregynon, Treharris, Troon, Truro, Tullich, Tummel Bridge, Turnpike Hill, Turves Green, Twechar, Tynewydd, Ubley, Uig, Ullapool, Union Mills (IoM), Upavon, Uplawmoor, Upper Killay, Upper Soudley, Urswick, Usk, Van Terrace, Voe, Wall, Walsden, Walsden South, Walthamstow North, Walton Le Dale, Wanlockhead, Wardle, Washford, Wattsville, Waunfawr, Weardale, Weaverthorpe, Weisdale, Welwyn, West Burton, West Lavington, West Linton, West Wycombe, Wester Erchite, Westwood, Whaley Bridge, Whalley, Wharfedale, Wheatley, Whitaside, Whitehead, Whitewell, Whittingslow, Whitworth, Widecombe In The Moor, Winchcombe, Wincobank, Windermere, Winshill, Winterbourne Steepleton, Wivenhoe Park, Wonersh, Wooburn, Woodcombe, Woodford Halse, Woodnook, Wooler, Wootton Courtenay, Worlds End, Wrexham Rhos, Wye, Yetholm, Ynys-Pennal, Ynysowen, Ystalyfera, and Ystumtuen
The 281 transmitters without radiation patterns are confirmed as:
Aldeburgh, Alderney, Amlwch, Angus, Arfon, Armagh, Ashbourne, Bagillt, Ballantrae, Barrow Town Hall, Barskeoch Hill, Beacon Hill, Beary Peark (IoM), Beer, Belcoo, Belmont, Benagh, Berrynarbor, Betws-y-Coed, Bevendean, Bexhill (new), Bilsdale, Bincombe Hill, Black Hill, Black Mountain, Blackwaterfoot, BlaenPlwyf, Bluebell Hill, Bow Street, Brading, Bridport, Brighstone, Brighton (Central), Brighton (Whitehawk Hill), Brixham, Broad Haven, Bromsgrove, Brougher Mountain, Burnham, Burnham on Crouch (new), Burnhope, Bushmills, Caerhendy, Caernarfon, Caldbeck, Cambret Hill, Camlough, Campbeltown, Caradon Hill, Carmel, Castlebay, Castlederg, Cemaes, Cerne Abbas, Chambercombe, Charmouth, Chartham, Chatton, Chelmsford, Churchdown Hill, Clachan, Clacton (new), Claudy, Clennon Valley, Clettraval, Coldean, Combe Martin, Conway, Coombe, Corfe Castle, Countisbury, Craigkelly, Croydon, Crystal Palace, Dalton, Darvel, Darwen, Dawlish, Derrygonnelly, Divis, Dolybont, Douglas (IoM), Dover, Dover B, Dover Town, Downderry, Dunoon Forest Row, Durris, East Dean, Eastbourne, Eastbourne (Old Town), Ederny, Edgebaston, Eitshal, Elham, Emley Moor, Exeter St Thomas, Fawley, Felixstowe, Fenton, Ffestiniog, Findon, Fishguard, Flint, Folkestone, Fremont Point, Girvan, Glenelly Valley, Glengorm, Glenmaye (IoM), Gorey, Gortnalee, Gosforth, Great Yarmouth (new), Greenhill, Guildford, Gulval, Hangleton, Hannington, Hartland, Haslingden, Hastings, Hastings (Old Town), Haverfordwest, Heathfield, Hollington Park, Holywell, Horn Street, Huntshaw Cross, Huntshaw Cross B, Hythe Marina, Ilfracombe, Ipswich Stoke, Isles of Scilly, Ivybridge, Jurby (IoM), Keighley Town, Kendal, Kilbride South Uist, Kilkeel, Killowen Mountain, Kilmelford, Kilvey Hill, Kimmeragh (IoM), Kingsbridge, Kirkoswald VP, Lancaster, Lark Stoke, Laxey (IoM), Leek, Leitrim, Les Touillets, Lethanhill, Lewes, Lichfield, Limavady, Lisbellaw, Llanddona, Llandecwyn, Llandrindod Wells, Llandyfriog, Llangranog, Londonderry, Long Mountain, Looe, Lowestoft (new), Luccombe, Lulworth, Luscombe Valley, Lydden, Lyminge, Madingley (Cambridge), Malvern, Margate, Mendip, Mevagissey, Midhurst, Moel-Y-Parc, Morfa Nefyn, Mounteagle, Muldonagh, Mynydd Pencareg, Newcastle, Newhaven, Newport Bay, Newry North, Newry South, Newton Ferrers, Occombe Valley, Olivers Mount, Overstrand, Oxford, Patcham, Penaligon Down, Penmaen Rhos, Penryn, Perranporth, Piddletrenthide, Pinwherry, Plumbridge, Plympton, Polperro, Pontop Pike, Poole, Port Ellen, Port Isaac, Port St Mary (IoM), Porthtowan, Portnahaven, Portpatrick, Portslade, Praa Sands, Preseli, Preston, Ramsgate, Redruth, Reigate, Rhondda, Ridge Hill, Ridge Hill (HTV West), Rosemarkie, Rostrevor, Rothesay, Rouncefall (new), Rowridge, Rye, Salcombe, Salisbury, Saltdean, Sandale, Sandy Heath, Sidmouth, Skriaig (Skye), Slapton, South Knapdale, St Austell, St Brelades Bay, St Davids, St Dogmaels, St Helier, St Just, St Peter Port, Steyning, Stockland Hill, Stokeinteignhead, Storeton, Strabane, Stranraer, Sudbury, Sudbury B, Sutton, Sutton Coldfield, Tacolneston, Teignmouth, The Wrekin, The Wrekin B, Torosay, Torquay Town, Torteval, Trefilan, Trefin, Trefor B, Tunbridge Wells, Ventnor, Waltham, Wells next the Sea, Wenvoe, West Kilbride, West Kirby, West Runton, Westbourne, Westward Ho, Weymouth, Whitby, Whitehaven, Winter Hill, Winterbourne Stickland, Woodbridge, Woolacombe, Woolwich, and Workington.
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Brian, are you up for doing anything to get the other radiation patterns off the BBC ?
I spoke to Ofcom again this morning and theyt repeated that they cannot think of any reason why the BBC should not release some of the transmitter patterns.
If, understandably, you`ve lost enthusiasm for it, I could have a go, but could you get in touch with me and tell me how to go about it ?
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Further to my last post I've attached a 50dbi powered internal aerial. I can get all Freeview channels with 100% clarity when antenna is vertical but not HD on ch21 474.2 MHz . Rotate it to horizontal and I get all HD channels but not all Freeview channels. Did the polarisation change in early December? When I lost the signals it was like someone had switched something off. Can anyone shed light on this please.
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Regarding the foi file and the radiation patterns.How did you determine which file is associated with each transmitter?Naively, I thought that the radiation patterns would be equal in all say vertical ddirections (for a vertically polarised transmitter), because the transmitter look like an omnidirectional antenna (single vertical pole)
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