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Recollections of BBC engineering from 1922 to 1997

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Date inserted	Title	(See end of table for Expired and Resolved* items)*
6-Dec-11	DK419 Mixing Desk	Victoria Forbes recently purchased a DK419 Mixing Desk in an auction of old equipment. Unfortunately, the faders were removed as souvenirs, and she would be pleased to know where she could get some replacements.
1-Dec-11	Gain adjustment on AM7/12	Flavio Encinas writes: "Now I'm ready to mount all of the units I have after testing the power supplies (all test perfect), but still missing a couple of details. On the pdf that you have sent to me there is a gain adjustment on AM7/12 modules that I don't know how to set, if it needs an external pot or if its a link I have to add between pins 8 , 10 and 11. If you can search for this information will be good for me. I'm still looking for any info on PS2/167 and nothing came up yet if you can find some will be fantastic. Thanks a lot."
10-Nov-11	TE1/7 transistor tester	John Sykes is seeking information on the TE1/7 Transistor Tester. Click the thumbnail to enlarge.
10-Nov-11	LL/106SA line transformers	Nick Sharwood-Smith has a couple of LL/106SA line transformers and wonders if anyone has the pin-outs and spec for them.
10-Nov-11	Unidentified early BBC Camera	Brian Summers writes: "In this picture of the experimental colour studio, the smaller of the two cameras is unidentified, the larger is a Marconi three-tube 3" IO RGB camera the BD848. The unidentified camera is a bit of a conundrum, in the early 1960s colour cameras were Huge! and this camera is very compact for a colour camera at that time. To me it has the look of a Marconi. From the size it must have used Vidicons in a two or three tube arrangement. I have asked the most likely person to know, who suggested it might be a Philips LDK2 precursor, I'm not so sure myself. There seems to be 2 camera cables at the rear, possibly BICC Mk4b, it was common at the time for colour cameras to have more than one cable. This would have given 6 co-ax circuits back to the CCU, R,G & B plus Live Drive (scan?) and return viewfinder. If anyone can help with the identity I would be very pleased. I have not seen this one before and have no other pictures of it. The original pictures came from Michael Barrett. Subsequently Brian added: I have found a bit more about the camera, it is a Philips 3 x Plumbicon experimental camera. There is a picture and a short description in the "SMPTE volume 73 page 475". There is also a reference to the Philips technical review 25 1963/64 no. 6/7 which may have an illustration.
10-Nov-11	Request for restoration	Jake Clark-Darby writes: "I recently obtained some equipment from a storage clearance from one of the engineers from Radio Caroline. Amongst some other things I have a rack with: 1x UN10/47 telephone control and balance unit 1x AM20/4 program peak level meter 2x AM6/18 limiting amplifiers (All in a 2U rack with power supply.) I would love to use this equipment in my studio and although it powers up it does not seem to function properly. Would somebody be willing to restore this equipment for me?
10-Nov-11	Faders: why pull?	Peter Neill asks: "When the BBC adopted quadrant, then linear strip audio faders, they chose that they opened as you pulled the fader towards you. The rest of the world seemed to choose the other direction. Were the BBC first and the others contrary or vice versa? Are there good reasons for either choice. The BBC has now adopted the "push" variety, but probably only because they now buy "off the shelf" kit. And, presumably computer controlled desks could be configured to do either. But are they?"
10-Nov-11	Mixer from BBC Radio Bristol	Ahmed of Studio 1999 writes: "Has anyone ever seen a mixer like this before? Its not like any BBC desk I have ever come across. Apparently it came out of BBC Radio Bristol. It is 12 channels and stereo with bass, treble, pan, echo and cue send on each channel. All the pcb boards have 'acorn' written on them. Any info much appreciated as I hope to begin to bring it back to life soon! Click thumbnails to enlarge:
10-Nov-11	BBC master clock, model CA1/6A/118	Robert Wilkes collects electric master clocks and has an old BBC master clock model CA1/6A/118 together with an SE1/1 changeover unit. He has managed to get it running again, but this was difficult without circuit diagrams etc. So, he is seeking any information such as circuit diagrams, service handbook and operating handbook. The circuit boards are marked with the following part numbers: AM24/1 (amplifier PCB), OS2/41 (oscillator PCB), UN1/160 (frequency divider PCB). He would also like to know what approximate year it would date from. Click thumbnails to enlarge:
7-Nov-11	Rolls Royce Radio!	David Adams would like to know if anyone can identify this picture (click to enlarge) and the occasion. He writes "It is a local Daventry photo obviously of the boy in front of a BBC vehicle. The Rolls Royce Club have identified as possibly a Phantom II or 20/25 chassis which were of used for hearses and ambulances etc. They suspect it was later obtained and modified as a BBC publicity vehicle possibly post 2nd World War. I wonder if it was to advertise the new Third Programme which started transmission from Daventry on MW in March 1950. The BBC Photo Archive are currently scratching their heads as are the RR Enthusiasts Club. The photo is in the Daventry Town Museum Photo Archive".
7-Nov-11	HF transmitting station on Antigua	Dave Porter is seeking the answer to this question from Mike Cooper. "DXLD coverage of the closing of the BBC Caribbean service makes me wonder whatever happened to the relay and monitoring station the BBC had on Antigua. The antennae, located on the eastern side of the island, were impressive. I vaguely remember hearing that the site was to be put up for sale years ago, but have heard nothing since. I wonder about the equipment (transmitting, receiving, antennae) and the land. Perhaps a DXLD reader has some insight? (Mike Cooper, Apr 3, DXLD)"
25-Oct-11	LSU10 speaker cabinet	Jimmy (London) is seeking a BBC LSU10 speaker cabinet(LB8).
23-Oct-11	DRD5 transciption turntable	Jimmy (London) is seeking information on the DRD5 studio BBC transciption turntable unit circa 1956. He has the upper part of the unit and is searching for the drive electronics and/or cabinet.
18-Jun-11	BBC Engineering Manuals	Chris Friedlander has kindly offered to provide information from various BBC Engineering manuals, within reason, on request: BBC Engineering Practice, BBC Technical Instruction S10, London Control Room operations manual. The equipment described in these publications was replaced by the BBC many years ago. Click here for more information.
7-Mar-11	ME16/3 standard level meter	Chris Friedlander has an ME16/3 standard level meter (the thermocouple AC one) and is wondering if there is any maintenance / calibration / schematic info around for this. According to the pcb the design drawing number should be D40934. He says that the unit seems to be working perfectly (after a long-ish warm up) and giving accurate readings. However, as with all these things, having service information would be wise insurance.
7-Dec-10	Frances David Northam	Holly Hesselgreaves would like to know more about her granddad Frances David Northam, who worked for the BBC in the 70’s & 80’s and passed away in 2002. It is thought that he was an engineer and as he probably lived in East Kilbride, it seems likely that he worked at BBC Glasgow studios or BBC Kirk O'Shotts/Blackhill transmitters. Any help would be appreciated.
6-Dec-10	Crowborough transmitter	Mark Casebow is working for BBC South East in Tunbridge Wells - on the Inside Out BBC1 show. He is making a piece about the Crowborough Transmitter, its role in WWII and its later life as a BBC transmitter and would like to get in touch with anyone who worked there - ideally during the war - but also afterwards. He would also be interested in getting in touch with people who have restored working equipment from the period that might have been used at Crowborough. Any advice or information gratefully received! (Many thanks to Doug Morris, Clive McCarthy and Mike Pollock who have already provided some information.)
6-Dec-10	Computer Originated World	Philip Pemberton is thinking about doing an FPGA reimplementation of the Computer Originated World, as shown on Andrew Wiseman's "TV Room" website, and elsewhere. He writes:- "I've got a pretty good idea how the hardware "might" work, but I have some questions about the BBC implementation -- specifically how the anti-aliasing worked (I'm guessing the 'landmass' data was alpha-blended), the compression method for the image data, and if any copies of the EPROMs and/or circuit diagrams are known to exist. (this would be an incredible long-shot, but it'd be nice to make the reimplementation as accurate as possible) I've been told that the design was done by Brian Mason but thus far I've been unable to find any further information. Do you have any idea how I might be able to contact Brian, or someone else who might know about the COW?"
31-July-10	Midlands Media Museum	The Midlands Media Museum has recently set up a website dedicated to the history of broadcasting in the Midlands. Its ultimate aim is to be able to create a museum (either in the physical sense, or as online documentation) of Midlands TV and radio production history. They are looking for kind, generous donations of broadcast memorabilia from the Midlands. Maybe it's old scripts, broadcasting equipment, props ... anything that represents the history of broadcasting in the Midlands region. They're also looking for people to write their personal memories for the website. Perhaps you worked at the old ATV studios on Broad Street in Birmingham, or worked at BBC Pebble Mill - they would love to hear from you.
17-June-10	Manuals for ACS test jigs	Herve Cherry (Senior Transmitter Engineer, VT Group, BBC Indian Ocean Relay Station, Seychelles) is searching for manuals or tests procedures to use the test jigs for the BBC TCPD designed sender interface and array interface unit cards. These units form part of the Automatic Control System (ACS). Please note that there are available notes and circuit diagrams for the unit’s individual cards, but no test procedures on how to use the test jigs provided for troubleshooting. The pictures below show the the units that he is referring to (click to enlarge). Any help would be most welcome.
30-May-10	Studer B62 documents available	Neil Gilchrist says: "In the early 1990s I purchased an immaculate Studer B62 (for £10!) in a junk sale at Kingswood Warren. With it I acquired 2 documents: a complete service manual for the Studer A62 (the same machine, but in a "portable" case) and an RD "provisional handbook" for the B62, which appears to have been written by Studer. Both documents contain circuit diagrams, but those in the latter are specifically labelled "B62". The playback amplifier circuit has a couple of alterations, made in blue ballpoint, but that's all." Neil has kindly offered to scan these documents and make them available. Please click on the link above if you would like to request a copy. You might also be amused, and pleased, to read this story about a Studer A80.
29-May-10	AM6/11 Limiting amplifier	Karl von der Linden says: "Im working professionally at synthesizer service department in Germany to repair access and other synthesizers. But also I'm a hobby recordist. I've got a BBC AM6/11 Limiting amp. I do not know if the machine works or not because I have no pin assignment for the two multipin connectors on the module or the schematics. If you can help me it will great. Many thanks for help.
19-Mar-10	Specific shade of Grey	Dan Sansom says: "I am about to do some restoration on some ex-BBC equipment that I have, and also a couple of old 1960s/70s Bay Frames, and I want to repaint some of it. My question is: what is the specific shade of GREY that these things were painted? I have scoured the web, but I can find nothing definite. Is there a RAL or BS381 number? I read 'Aircraft Grey' somewhere, but I want to be certain. Thanks in advance for any help."
13-Mar-10	Local Radio Mk 3 Desk	James West says: "I'm interested in the development of the BBC Local Radio Mk 3 Desk, particularly the prototype installed at Radio Cumbria, any unusual variants such as the "music" version installed at Radio Merseyside and commercially produced versions by the likes of Neve. Do you have any information or pictures that would help please?"
13-Mar-10	AKG C414EB microphone	Ahmed of Studio 1999 says: "I recently bought an AKG C414EB microphone and it appears to be ex BBC. It has 'BBC OU 2' engraved on the front and 'BBC MK 03803' on the rear. If it is ex BBC is there any way of finding out any history on the mic.? Photos attached. Thanks". Click the pictures to enlarge them.
6-Mar-10	Grams: EMT 950/948/938 or similar	Lee Gardner is seeking Grams such as EMT 950/948/938 for the construction of a functioning 1990’s style radio studio. The project is intended to replicate a Radio 2 transmission suite studio (1G, 1H, 1J) as they were after the 1993 refurb. He would be most grateful if you could point him in the right direction.
5-Mar-10	HMV Concert 600 Electrical Reproducer	Mike Cronk is refurbishing an HMV Concert 600 Electrical Reproducer (amp and speaker) and seeking some drawings. In particularly he is keen to get some drawings of the speakers to see how the metal foil attached itself to what he believes is a moving coil. He also wants to find a source for the foil. He has tried the IET archive with no luck and also the gramophone museum. Any help would be appreciated.
5-Mar-10	Ken Chapman	Jamie Searle works as the engineer at BBC Radio York, having spent the early 1980s at Equipment Department in Avenue House, Chiswick, assembling and testing the BBC Local Radio Mk 3 mixer- these desks are still in service in several radio stations, including York! At the time he worked with Jeremy Lowe (now working at World Service) and Ken Chapman who was their supervisor. He is still in touch with Jeremy but would like to make contact with Ken. Any leads would be appreciated. Here is a picture from the test lab in 1985. Jamie is wearing the bow-tie and Ken is standing next to him. Click the picture to enlarge it.
Items that have expired (after one year) or been resolved
6-Dec-10	Transmitter at Bartley near Southhampton Resolved	Dan Goldfarb writes: "Until 23 November 1978 (i.e. on the implementation of the Geneva Plan), the BBC used at least one 10kW AM transmitter at BARTLEY. I understand that there was even an engineering maintenance unit based there." "Is it possible for a retired engineer or BBC records to give either Geographical Coordinates of where the transmitter site was or else what road is nearest to it?"
11-Mar-11	EMI type 903 desk (Painton Faders) Resolved	Iain Elliott (Chairman, Bristol Hospital Broadcasting Service) writes: "Hi I've just been browsing some of the BBC pages and found your request for Painton Faders. We have an old EMI type 903 desk circa 1962 with all the bits. We don't use it now and would like to dispose of it to a happy home. It was originally installed in the TWW studios in Bristol, they then donated it to us (Bristol Hospital Broadcasting Service and we used it in our OB vehicle. The meters are missing but all the channels and groups are there. I also have more or less complete circuit diagrams." Contacted by Ahmed of Studio 1999, see next item.
29-July-10	Painton Quadrant faders Resolved	Ahmed of Studio 1999 says: "I am building a vintage EMI style mixing console and looking for the following parts. Painton Quadrant faders and Ernest Turner 701 and 702 meters. Please can you put my request on the site." Contacted Iain Elliott, see previous item.
15-Nov-09	Radiophonic Workshop Expired	Richard Hollingum (University of Northampton) is researching into the pre-history of the Radiophonic Workshop, including the various strands in radio that developed after the Second World War that led to the creation of the Workshop in 1958, where his research ends. Part of his research is through oral history and he would be pleased to talk to, and record, anyone employed by the BBC in an engineering capacity during the period 1945-1958.
15-Nov-09	UN1/715 video measuring unit Expired	Brian Summers (who runs www.tvcameramuseum.org) is on the lookout for a handbook for the UN1/715 video measuring unit (weaver box). He has one in use and sooner or later it is bound to stop working! Please also see lists of other 'difficult wants': TV and Radio.
15-Nov-09	Eddystone receiver Expired	Chris Pettitt is currently researching an Eddystone receiver that was used by the BBC in 1956/7 to monitor band 1 and band 2 transmissions. It looks to be a special version of the Eddystone S890 which was sold to the BBC as a radio microphone receiver. The set has a designation which he thinks confirms it as BBC property HR/20A/176. Do you recognise this kind of designation? Do you know what the set was used for: local station monitoring or rebroadcast perhaps? Any information would be helpful. Click the picture to enlarge it.
22-Sep-09	Ottringham - OSE5 Expired	David Porter would appreciate any extra information that a reader of BBCeng could offer re Ottringham. See the article on Aspidistra and OSE5 in Technical Reviews.
22-Sep-09	Mystery BBC vehicle Expired	Catherine Porter writes: "I'm about to be the proud owner of an gold (believe this is the original colour) H reg (1990) VW Caravelle gl. The current owner tells me the van was originally used by the BBC as an outside broadcasting unit and I'm very keen to get more background on it, a picture would be fabulous. The van was then sold to the owner of a gym and then to the present owner in London. The current owner also told me that before he converted it to a camper the walls were lined with a bright green felt material and it still had some of the transmitter items and generator inside. The only tell tale sign of it's previous life are 6 black 'knobs' evenly spaced out on the roof (I have no idea what the use was). If you can shed any light on this or know of anybody who may be able to help I'd be very grateful. The owner was told by owner number 2 that there were pictures of it being used at a cricket match somewhere in England but I know this doesn't give much to go on. I've just received the old copies of the vehicle log book and the 1st owner listed is Britsish Broadcasting Corp CW Lease UK Ltd, CW House, Cookham Road, Bracknell, RG121RR. Perhaps this leasing firm will jog someone's memory."
25-Aug-09	Novachord Expired	Dan Wilson, an electronic design engineer & vintage synth enthusiast writes: "I'm currently importing an extremely rare 1939 Novachord into the UK. The Novachord was the world's first commercial polyphonic synthesizer, released in 1939, containing 163 valves and weighing 1/4 ton. The reason why I mention this is that I've been told that the BBC had several of these extremely expensive instruments ($1800 in 1939) during WWII and one of the most famous users was Arthur Young who played with Vera Lynn in many of her famous recordings. I have been advised that my instrument is one of few surviving in the whole of Europe - I am now very keen to know if there is just a chance one of these fine instruments is in storage or on show somewhere at the BBC." I am sure that any other relevant information would be of interest.
25-Aug-09	Hadrian Jeffs, Pulham Airstation Expired	Terry Clarkson of Dickleburgh and Rushall Parish Council is trying to contact Hadrian Jeffs on a matter pertaining to the Pulham Airstation. If you know how to contact Hadrian would you please let Terry know.
12-Aug-09	Audio Test Set Expired	Michael Ward writes: ".... looking for EP14/1 Audio Test Set line-up / calibration info. Maybe circuit info as well if possible. Thanks.
17-Jul-09	Studer A80 remote Expired	Sean Williams writes: "I have a couple of ex BBC Scotland Studer A-80s with the BBC fader start section on the right hand side. I am unable to get the fader start to work and am wondering whether this could be to do with the EDAC connector needing to have some pins shorted for full functionality. I have another A-80 remote control unit but this does not function either, when used with the ex-BBC machines. I am wondering whether there is some critical modification that has interfered with normal remote operation. What I am trying to do is configure remote operation generally and to install Capstan Control so that I can use the +/- 7 semitones varispeed for use in the studio for making Musique Concrète. This is part of my PhD research into the physicality of early electronic music practice. Any help or advice on working out the remote control functions would be greatly appreciated."
16-Jun-09	Sony VO 7630 Umatic Video Recorder Expired	Roy Phillips says: "I have recently purchased a Sony VO 7630 Umatic Video Recorder, from a large corporate AV Department that was closed down. I understand that this machine was used by the BBC TV production in large numbers, but is now generally obsolete. It is very difficult to obtain help from Sony for technical help. I am wondering if your library has a copy of the technical handbook for this machine ? I would be pleased to purchase a copy, should it be possible, or just a pdf/photocopy of the connection field at the rear of the machine. Although it is generally obvious what the inputs and outputs are, I would particularly like to have the connections for the TV Recording socket (this is a 8 pin Cinch socket), and what the connections are to the Dubbing in/out connectors (6 pin), I do not recognize the manufacturer of these latter connectors. Trusting you may be able to help to keep this excellent machine in full use."
19-Apr-09	Painton faders Expired	Erik Alderink would like to know if Painton faders are balanced, and how many steps they have. He says "I live in the States, and seeing one in person, let alone opening one up is an impossibility! Thanks for your time, any information would be greatly appreciated."
19-Mar-09	Studer B62 Expired	Doug Fisher would like to obtain (for a friend) a copy of the circuit diagram of the Studer B62, as modified by BBC Designs Department. Help would be much appreciated. Johan De Haan would also like a copy.
8-Mar-09	Woofferton staff list Expired	Jeff Cant would be pleased to receive an email from ex-Wooffertonians who do not yet appear on his tentative WOF Staff list. He would like anyone who qualifies to contact him with details of their service at this transmitting station.
3-Mar-09	Calrec J series MK2 Expired	Brian Moran is hoping that someone may be able to help: "I have part of a Calrec J series MK2 of which I am trying to complete restore and put back into action. So far I have an eight channel bucket loaded with PQ-14s, RL-23s & Painton faders. I also have in my posession the Monitor section. Therefore my first stop is to find an echo return section and hopefully more mic pre input console sections. These could be complete or various modules console frame, PQ-14s PQ-15s etc. Any help would be much appreciated."
12-Feb-09	Crowborough Expired	Doug Morris is seeking information, including photos and diagrams, of the the ASPI1 and other transmitters at Crowborough. He has "collected" virtually everything, pictures and information, that is available on the internet and has the following books "The secret Wireless War" by Geoffrey Pidgeon, 'The Secret History of the PWE' by David Garnett and 'The Black Game' by Ellic Howe.
2-Feb-09	BBC recovery vehicle Expired	Andy Lambert is seeking information about BBC Recovery Vehicles. At this web site you will find one of the many picture galleries that he hosts on his vehicle recovery site. The 15th vehicle down is a BBC recovery vehicle from around 25 years ago. The 14th picture has been suggested is the same vehicle some time earlier (He cannot see it himself). The question is does anyone know if it was re-boded, or if there were two of them, perhaps at different times.
29-July-10	Curriculum for A/B/C Courses Expired	Andy Hasluem, a veteran of BBC WN A79 course (TV) 1980, now works for Turner Broadcast in the US, and the Company is petitioning for his Permanent Residency (Green Card) with US Immigration. They need transcripts (details) of his course of study for the BBC Engineering Certificate, to evaluate his (foreign) education. That means the curriculum for his A/B/C Courses, and timeline if possible. He needs this information urgently, so would greatly appreciate any help. Records of courses from this era are no longer kept by the BBC.
29-May-10	PB1/L1 rotary faders Expired	Martin Kin says: "I am looking for one or more PB1/L1 rotary faders and housings for a Type A restoration project. I am also looking for hybrid transformers and anything else of interest related to this series of equipment. Please would you kindly post this message on your noticeboard - perhaps someone out there can help?. Resolved with help from John Phillips.
13-Mar-10	LL/81MSC Audio transformers Expired	Martin Dale (G6ABU) says: "I'm looking for any data on this and other similar audio transformers as used in BBC engineering equipment; Also LL/75MSC, LL/76MSC, LL/85ASC LL/88MSC Any info would be gratefully received such as impedance, wire colour / connections, ratios etc. I have trawled the web but no joy. Am I right in assuming these were made for the BBC by Gardners?" Resolved with help from John Phillips and John Meredith.
27-Jan-10	AM6/18 Limiting Amplifier and EQ3/27 Resolved	Tom Giles is looking for schematics for an AM6/18 Limiting Amplifier and an EQ3/27 Octave Equaliser. He has contacted the BBC to get schematics or service manuals for these 2 units but no joy yet, so any help would be appreciated. Resolved by Mark Timlin. Details available on request.
13-Nov-09	Frequency Standards Resolved	Paul Strickland is looking for old frequency standard equipment to display at The Time Machine. He would like to know who dealt with such matters in the BBC and what is happening to the frequency standards of the 'old' analogue transmitters. Resolved by John Philips
31-Jul-09	Radio 3 Medium Wave Mast Resolved	Chris Maxwell is seeking details of the design of the old now long demolished Third Programme / Radio 3 Medium Wave Mast that used to be at Dodford near Daventry. This 725 feet high split mast radiator operated on he believes 464 Metres – 647 KHz. He is particularly interested in the feeding arrangements of the two sections and the theory of it’s anti fading design. Any information would be greatly welcomed. Resolved with help from Clive McCarthy, Ray Cooper, Richard Lamont, Russell Barnes and Terry Beswarick.
8-Jul-09 10-Jul-09	Audio transformers Resolved	Geoff Atkins has just acquired a couple of BBC wire-ended audio transformers, type LL/88ASC, and would like to know the spec and the colour coding of the five connections. If anyone could help he'd be very grateful. Reply from John Phillips: I have found the following listed in Registered Designs and Coded Equipment Volume 2 dated April 1966:- Impedance ratio 1/1, 600/600 ohms. Colour codes for lead-out wires :- Highest impedance winding start = yellow, finish = blue. Next highest impedance winding start = red, finish = green. Screen = black. The usage is listed as General Use. Hope this helps. I knew my archives would come in useful eventually!
24-May-09 3-Jul-09	Galdenoch Radio Station Resolved	Peter Linzey is seeking information about this station near Stranraer 54.55N 05.10W which was built around 1942/3 to contain qty 2 ST&C CM8 LW 10kw broadcast transmitters, together with 4 off 315’ steel stayed masts arranged star formation, with aerials slung between them . He says that they appeared to be well pre-war designs, Litz wound coils, watercooled valves, frequency around 120khz, and never appeared to have been used. The station was occupied soon after by the USAAF signals who put their own gear in for air traffic purposes. Peter worked there 49 to 59, employed by Min of Civil Aviation, and eventually the CM8s were used for RTTY testing with BOAC aircraft. What was the reason for the station being built [around CM8s]? Did the BBC have any requirement/involvement? Peter is trying to write a history of the ‘early days’ of the unit, and this question is a major stumbling block. Any help would be appreciated. 30 May....I’ve now had a bit more news from our Estates Branch [whose records don’t go back far enough to be much use to me] to the effect that after the Air Traffic service from Galdenoch closed in mid-1970, the BBC had a ‘sub-let’ from NATS/CAA for a couple of years, and operated from the site. Have you any idea / can you point me where to ask what the BBC were up to? Doug Jordan explains: "It was a reserve in case either Lisnagarvey or Londonderry (can't remember which) took a hit during the terrorist campaigns. It was a T fed antenna and the transmitter was housed in something similar to a horsebox, if you want more info contact me."
8-Mar-09	AM1/4 and AM6/8 Resolved	Ahmed of Studio 1990 says: "I have a small rack containing 2 BBC AM1/4 RSAs and 1 AM6/8 limiter. I need them serviced but my engineer needs diagrams. Can you help me locate these diagrams? I would also be interested in what their original use would have been? I am using them as part of my recording studio setup as I love the sound of them and would have more if I could find them!" Partially resolved with help from Geoff Atkins.
2-Feb-09 12-Jul-09	TS10 and Amp-Det Resolved	William Blankley would like information on the TS10 and the associated Amp-Det. He wishes to build a modern version as he suspects that he will never find the originals at an affordable price. In particular, what was the circuitry around the 6BA6 meter-driver valve? Also, has anyone got a spare LL106S rep coil please? Information on TS10 provided by Geoff Atkins. Rep coil offered by Keith Orchard.
12-Jan-09	BBC broadcast mixers Resolved	Charlie Davy is looking for some information on a couple of BBC broadcast mixers... Specifically, the ones used at Radio 1 in Egton House from the late 80s until Mid-90s, and a BBC OB desk (which is also similar to the one in use at BBC Manchester) pictured here: http://www.flickr.com/photos/ledgard/82088858/sizes/o/ He is curious to know if these are made by the BBC or somebody else - there isn't much information on them. Aside from a few videos on YouTube about Radio 1 that's all there is. Resolved with help from Jim Harpur, and John Meredith.
1-Oct-08	BBC mobile recording equipment vans during WWII Expired	Phil Waterman is looking for information about BBC mobile recording equipment vans during WWII, as he has a truck which was used by the BBC in New York City at the end of the war. If you are interested about information on the truck and information he has tracked down take a look at this web page www.canadianmilitarypattern.com where he has information about the truck including video of it covering a parade at the end of the Second World War. While interested in all aspects of the mobile equipment, he is particularly interested in photos or list of equipment that the these vehicles would have carried. He has owned the truck for nearly 30 years and it and its history always draws interest at antique car and truck shows. Any additional information will be greatly appreciated.
19-Sep-08 20-Oct-08	Player for 10 inch tape reels Resolved	Trevor Carter is in possession of a couple of reels of original high quality, master, audio recordings of computer sound tracks from the 1980's. They are on 10 inch spools and recorded in stereo. He would like to convert these analogue recordings to digital media for use in present games software but does not have access to a good quality stereo reel to reel tape deck to play them back on. Does anyone know where he might find one or of any BBC professional means of doing the job? Trevor works in education and would be willing to engage in the task as a school based project for young people.
9-Jun-08	AM6/7 Expired	Waynne Smart recently bought from eBay a BBC AM6/7 Limiting Amplifier (No.254) and two power units PS2/4. He would like to get the unit restored and back to full working order and set in to its own rack unit with XLR in/outs with the power supply. He is looking for someone who may be able to restore and rack-mount the units for him. He would also appreciate help with sourcing the circuit diagrams. Click here to see the unit on eBay. The RD&CE book lists the following: AM6/7 - Programme Limiting Amplifier for transmitters and unattended studios and as a compressor for "pop" music types of programme. Includes noise gate. Voiceover input, top tilt for use at FM transmitters, and relay to guard automatic monitoring apparatus. CHl/26B, Pegs 23, 39. DD 1968. DD Spec 3.471. DDHB 3.94. EDI. ACO. OBSOLESCENT
4-Jun-08	BBC Leeds Expired	Stuart Childs would like to get in touch with people that used to work in the BBC Broadcasting House based on Woodhouse Lane in Leeds. He is currently conducting some research into the history of the building, with the aim of curating some interviews and photographs for an exhibition in the newly - renovated building.
23-Apr-08	Brian Fitt Resolved	Patricia Hunt Chase would like to get in touch with Brian Fitt. She may be a distant relative of his from the States. Brian is mentioned in Eng Inf No.11 as he was SCPD project leader for refurbishment of the Greenwood Theatre starting in 1979. Resolved by Brian Fitt.
11-Apr-08	DK4/16 presenters desk Expired	Jim Harpur writes: "I'm the proud owner of 2 x RP2/8 disc reproducers, and what's left of a DK4/16 presenters desk. The turntables still work pretty well, but only the 'bones' of the mixing desk survive. I would like to rebuild the 'desk', but have no circuit diagrams, or plans for the wooden framed desk. I wonder if anyone has any old 'plans' to help me with this project. Many thanks, Jim" According to the Registered Designs and Coded Equipoment book: The DK4/16 is a "Studio Presenter's Desk, used in Radio 1 Club programmes, with 2 RP2/8. Contains 8 channels channels. Transportable wooden desk, formica clad. DD 1972. DDMI 3.548. DDTM 3.125. EDI 10148(1)OCT72."
31-Mar-08 14-Nov-08	GE6M/564 Picture Store Resolved	Brian Summers (G8GQS, www.tvcameramuseum.org, ex BBC outside Broadcasts) writes: "As part of my camera collection I have a GE6M/564 general purpose picture store. It is a 4U high "silver unit" and it is in good condition and works well. The picture stored in the unit's EPROM's is the Eurovision identification logo. In addition it makes colour bars and a few other test signals. As I would like to keep this as part of my working collection I would like to acquire some information, the handbook and circuits. It's certain to stop working one day! I am also interested in details of the EPROM's and if it is feasible to program other pictures. Has anyone else got one?" 11-Apr-08: Comments from Richard Russell: "I don't know a great deal about the GE6M/564, but here are a couple of comments which may be of interest to Brian Summers: 1. The EPROMs are described in the EDI sheet as '128 k' which is somewhat ambiguous because it could mean 128 Kbits (i.e. the devices would be 27128s) or 128 Kbytes (the devices would be 27010s). It should be easy to determine which they are, because a simple calculation suggests a Rec.601 frame would require around 64 of the former but only around 8 of the latter. 2. It should certainly be feasible to program other pictures into the device (always assuming a suitable EPROM programmer is available) although the data format might be difficult to determine, especially if no circuit diagram can be found. I would caution that there is a possibility it needs Cb and Cr data separated by 74 ns rather than the co-sited samples specified by Rec.601. If so an interpolation process would be required as part of the data preparation. Regards, Richard."
15-Jan-08 14-Nov-08	Preservation of BBC Vehicles Partially resolved, as various contacts have been made regarding BBC vehicles. Entry moved to this Expired/Resolved area to save space in the Current area.	Phil Upton writes: "I have only just discovered bbceng.info and have been very intrigued by the items regarding Eagle Towers. I am sorry I missed the original enquiry from Neil Bennett as I would have replied instantly, although I could not have improved on the excellent account given by Jeff Longbottom. I too possess a treasured set of Dinky OB vehicles - models of vehicles still in use during my time on O.B.'s ! However, I was particularly interested in the reference to the two 100ft. towers mounted on the Leyland Lynx chassis because I, for my sins, was project manager for the design and construction of those vehicles, a two year nightmare when I was with TPID/TCPD Links Unit. I have long wondered whether anyone, anywhere, has had the brains to preserve one of the original 60ft. towers which were the backbone of Tel. O.B.'s for so may years. I have a presence in the commercial vehicle preservation world - my pride and joy is a 1927 Austin 7 delivery van - and at rallies I regularly see preserved GPO, RAC, AA and municipal vehicles but NEVER a BBC vehicle. The nearest was a beautifully restored flat bed truck whose registration I recognised - one of the RXX series which were in the BBC fleet for years. It was originally a film unit generator vehicle but was sold minus the generator and the current owner has done a lovely restoration but of course it is not in BBC livery. I briefly became Acting Assistant Transport Manager after TCPD and it was part of my job to dispose of redundant vehicles. I had to do so under some fairly stringent rules laid down by the BBC Governors designed to prevent ex-BBC vehicles falling into the hands of serving staff which, the Board believed, could have led to accusations of sharp practice. As a result, all vehicles went to open auction and I suppose they just melted away into the second-hand market. Does anyone know of any BBC vehicle which has escaped into preservation - especially an Eagle Tower!" 5-Feb-08: Comment from Chris Collingham: "I have just read the note from Phil Upton regarding Eagle Towers. I worked for BBC Comms Dept London for many years including attachments to Radio Links in Manchester and Birmingham and frequently worked on 60ft Eagles. I also had an attachment to TCPD working for Phil and spent many months at Brookmans Park helping to put together the first 100ft tower, he may remember me. I have also wondered if anyone had the foresight to save one, I am still trying to find a Dinky model in reasonable condition, in fact a search for that led me to the BBCeng.info site. When working on Match of The Day in the North, I was always impressed by the Granada Eagle Towers as they were so much shinier than ours as well as having chrome wheel trims! They always turned up in pairs as apparently an OB was once lost because the tower could not be erected. Following an accident one of the Manchester Eagles had its cab replaced by one from a 'Green Goddess' fire engine complete with flashing lights which of course were never used! After 11 years at the BBC I left to become Chief Engineer TV-am and held a similar position at Channel 5, I am now helping the BBC with their HD channel."
15-Jan-08 14-Nov-08	Audio Limiter Mk II Resolved	Dennis Johansson has in his possession an old and not very common BBC made compressor. It is called "Audio Limiter Mk II" and has the serial number 13. He has asked a few BBC people about it before but no one knows what it is. Could you maybe shed some light?? It has the same inductor "delay" board as other BBC comps as AM6/7 and AM6/17. You can see a picture of it here. A contributor has pointed out that there is a discussion on the BBC Audio Limiter MkI in a BBC monograph, published October 1967. There is a picture of the experimental unit on page 14.
6-Dec-07 10-Jan-08	Unknown microphone in BBC Heritage Collection Resolved	John Trenouth, who's sorting the BBC's Heritage Collection, has come across an unknown microphone and wonders if anyone can help. "It looks like a “one-off” and as such I suspect it’s a BBC made one. It’s beautifully made, a capacitor microphone with a capsule about the size of an AKG C451 capsule. It has a miniature “apple & biscuit” arrangement on the end of the body which is about 7 inches long by 1&3/4 inches diameter. The body is silver plated (real silver) and is removable (by depressing a latching pin) to reveal the insides. The electronics comprise an EF40 with encapsulated resistors & caps. The capsule remains inside the body, removable by unscrewing the top end of the body. There are no markings at all on the microphone except a small engraved arrow to help align the body with the latching pin. Surprisingly the connector is a 3-pin XLR (with an additional screw fitting – like an oversized inside-out tuchel!). I assume that pin 1 is earth, pin 2 is 6.3volts for the heater (must be DC?) & pin 3 is HT in & signal out (assuming that the anode resistor is in the (missing) power supply). Somebody must recognise it. There is a very faint suggestion that it may have been designed as a “Royal” microphone." John Trenouth discovered (not via bbceng) that it was made by Philips. It has an omni pickup pattern & was apparently much liked for single microphone orchestral pickup. The capsules were slightly variable (ie inconsistent response between “identical” microphones) and the connector was unreliable. It had to be used with a dedicated filter network.
3-Dec-07	Painton attenuator Resolved	Brian Moran is seeking a part for a PYE 84 4060 compressor/limiter and thought that there may be a similar part that has been used in some other BBC equipment. The part he needs is a Painton attenuator. The part number he has is 'G.S102784/763'. Any help would be much appreciated.
3-Dec-07 31-Dec-07	AM6/14 Resolved	Richard Barnes would be very pleased if someone could let him have a circuit diagram for the AM6/14 "delay-line" audio limiter. Unfortunately this circuit is no longer held by BBC Research. This limiter is in an "imperial" (white-fronted) chassis 3U high and 2 BBC Units wide. It was used in local radio stations in Leeds, London and Manchester, plus the desk in the Langham Local Radio Training Suite, which was later transferred to Radio Sheffield's Cubicle 2. None of these desks still survive. They were very good limiters, better than the the later BMM series, but the circuits seem as rare as hens teeth! He is still kicking himself for not liberating a copy of the circuit when Radio Leeds moved, only a couple of years ago! Response from Richard Barnes: "I have now received the service manual for this unit, including the full line-up details, from Brian Summers at the TV Camera Museum. I also had an offer of help from Mike Davies, and Brian Moran put me in touch with a guy in Denmark who sent me what he had. Altogether a very satisfactory outcome. Many thanks for your help, all power to your website, and a Happy New Year!!!!" Subsequently, an offer of help also came from David Porter.
3-Dec-07	Cromer Resolved	Sean Cooper has a request regarding the MF site that never was ... at Cromer! He has found out some information about this former Home Service site (e.g. it was actually at Hempstead near Holt, Norfolk), but would love to hear from any website visitors if they have any info, plans, logs, photos and/or stories of this site, however small. He is particularly interested to know what frequencies were used, when they were used, any transmission specs and when the site was finally closed down and dismantled. If any one has any of the BBC Radio Transmitting Station Handbooks from over the years (mainly 1950 to 1988) he would particularly love to hear from them, or even have scans of details about the 'Cromer' site. Resolved with help from Hadrain Jeffs and Martin Brown.
3-Dec-07	KEF LS5/1 LS5/1A Resolved	Malcolm Jones was at KEF from 1961 - 74 and is writing a book on the early days of the company. He will be writing about the LS5/1 and LS5/1A as they used to build some and converted them into the active version LS5/1AC. He is interested in the differences between the 1 and 1A. Any information would be appreciated. Resolved with help from Richard Carruthers.
6-Sep-07 14-Nov-08	Transformers etc. Expired	Stuart Winsor has, over the years, "broken up" some old white fronted bookcase units and he has a quantity of mains and audio transformers and other odd bits which might be useful if anyone is trying to repair/resurrect such. He also has some old TIs and information on quite a number of BBC transformers.
28-Jul-07 14-Nov-08	Painton faders Expired	Wilfried Kobiolka is looking for old quadrant Painton faders. Do you know where he can find such things. Type Number: GS 100 345 or GS 100 349.
31-Dec-07	SCPD monthly news magazines Expired	It has been suggested by Rik Brooks that it would be good to include SCPD monthly news magazines on this web site. If you have a copy of any of the issues and would be willing to help, then would you please email Martin Ellen.
28-May-07 14-Nov-08	Neve General Purpose Radio Console mk IV Expired	Marco Manieri has just purchased one of these mixing consoles, production no. 10180, from a broker in England. The broker did not have any documents whatsoever. Luckily, Marco is in possession of a technical manual for a similar desk, only from a different production run, and it appears that some wiring differs. He would like to get in contact with someone who might be able to help him track down any further documents.
3-Feb-07 14-Nov-08	Broadcasting history in the South West Expired	Tony Byers is researching the history of broadcasting in the South West with the aim of setting up an oral history archive based at BBC Plymouth. This will include interviews with former staff. He is interested in hearing form anyone who worked at Start Point or BH Plymouth in the war years or the immediate post-war period. He is also trying to find out what programmes were made at BH in Seymour Road in the 50s and 60s. One aspect he is trying to find out more about is the visits of war correspondents, including Frank Gillard. If anyone has any information, recordings or photographs dating from the war onwards please get in touch.
30-Jan-07 14-Nov-08	"Secret" sites and Mobile Transmitter Units Expired	Martin Briscoe is often asked about the old Deferred Facilities network, though like most people he was never told much about it. He remembers visiting a site at Normandy near Guildford which he would describe as "covert". How many more of this type of site were there and have any survived? If anyone has any photographs he is sure that Sub Brit and others would welcome seeing copies. Also, does anyone know the background to the Mobile Transmitter Units, or have any photographs of them when still equipped inside. As far as he knows there is there is just the one left rotting away which seems a shame as it should really be saved.
4-Sep-06 14-Nov-08	LSU/10 loudspeakers Expired	Tom Goulet has now received a Technical Instruction on LSU/10 loudspeakers, as requested below (The drivers inside turned out to be made by Parmeko and not Pamphonic). He is now looking for an original amplifier. If you can help then please make contact via the above link.
29-Jan-07 3-Dec-07	Tacolneston Cancelled	Sean Cooper is trying to write an article for his website about the history of the Tacloneston transmission site. He is researching the history of this Norfolk broadcast site, it's transmitters, operation, construction, etc as it is celebrating 50 years. Any help, and/or photos (especially from the earlier days) would be greatly appreciated. Please contact him via his web site. See also the 20-Mar-06 entry below. Project closed, but see request regarding Cromer dated 3-Dec-07.
21-Aug-07 26-Sep-07	BBC TV OB vehicle with elevating aerials Resolved	Neil Bennett is interested in the BBC television vans with elevating outside-broadcast aerials, referred to in the journal "Engineering" 11 Jan 1963. The elevating structure or ladder was made by the famous Merryweather & Sons company, which he is researching. It is likely that the DINKY TOYS model no. 969 ("TV Extending Mast Vehicle") was based on this (and he has an example). It looks a bit like a Green Goddess fire engine. Can you share with Neil any information or pictures on the 'real' version of the Dinky model, and (if different) the van(s) with Merryweather components? Also, he would love to know where the 'rotting' vehicle is. Neil has provided these three pictures of Dinky models of BBC vehicles: the Extending Mast Vehicle, Roving Eye Vehicle and Mobile Control Room (from Vectis Auctions website). Information on the 'real' version of all three is welcome, but can anyone confirm or expand on Merryweather's involvement? As a result of the notice above, help came from Jeff Longbottom who provided this good reply: Merryweather & Sons did supply such vehicles to the BBC but only up to 1951 and in view of the fact that the original one on which the Dinky model is based was not put into service until after 1952 then this does not apply. The vehicles on which the model is based were in fact built by Eagle Engineering of Warwick and somewhere in the region of ten units were eventually supplied to the BBC over the next five years. Identical examples were also put into service with ATV and Granada and were known within the industry as 'Eagle Towers'. In the case of those supplied by Merryweather, the original examples were provided on loan, the first such one dating from 1937 and was just a basic fire appliance to which an aerial was attached at the top. The first custom built model was put into service in 1938 and had an enclosed body mounted on a Albion coach chassis with the mast being capable of being raised to a height of 80ft. No further developments took place until after the war when a second example based on a Fordson 4X4 vehicle was purchased from the MOD in 1951. Two further examples were obtained from Merryweathers in 1951 which were rather more sophisticated in that they had aerials which could be raised to 100ft and also incorporated a transmitter and generator. These also had enclosed bodies and were based on AEC Regal coach chassis and were known as PTAs (Power Transmitter Aerials) and were to be the last purchases from the company. As mentioned above all future purchases were to come from Eagle Engineering with the common factor of having 60ft 3section triangular masts mounted on Bedford 4x4 chassis and this became the standard model. The final versions of this type of tower were supplied in 1973 on Leyland Lynx chassis and differed in the fact that they had 100ft towers. Future purchases came in the form of Simon Engineering hydraulic hoists and as before were operated in both 60ft and 100ft versions usually mounted on Leyland Freighter or Constructor chassis. Nowdays of course there is no requirement for such vehicles as all transmissions are uplinked via satellite from van mounted dishes, commonly on Mercedes Sprinters. All three Dinky models are faithful representations of the originals. The original of the Extending Tower was put into service in 1952 while the Mobile Control Room is based on a batch of four Bedford vehicles put into service in 1954. The third model in the set, the 1956 Karrier Bantam based Roving Eye was a second version of this type of vehicle operated by the BBC and was designed to be operated 'on the move' using two cameras. One camera was mounted on a gun ring on the roof with the second one mounted in the passenger position in the cab area to provide a view through the side, hence the enlarged passenger window. It also carried an onboard generator and had a pneumatic mast capable of being raised to a height of 45ft (but not while roving !!!). Surprisingly, Dinky never modelled the fourth type of vehicle employed on outside broadcasts, the radio links van although two models in the set, the control room and roving eye, were later produced in the colours of ABC Television as a control room and a links van even though the company did not operate these original versions. (See the Studio and Outside Broadcast Operations page for a relevant picture.)	Click to enlarge
28-Jul-07 10-Aug-07	Audio Line Amplifiers Resolved	Marnix Bosman has found a complete rack carrying AM7/11, AM7/12 and AM7/13 units and he would like to get them going again. Therefore he is looking for the schematics or the pin layout and hopes there is somebody able to help. Information provided via new arrangement with BBC (see next item below). Further information offered by Mike Davis and Richard Barnes.
7-Jun-07 10-Aug-07	AM6/21 and UN4/6 Resolved	Pablo Kahayan repairs and restores equipment for professional recording studios in Spain. He has two AM6/21 and two UN4/6 units to repair and he is seeking information, in particular schematics for the UN4/6. Information provided via new arrangement with BBC, as reported on Home page and copied below. Further information provided by the designer, Mick Gleave. The BBC has kindly established an arrangement whereby circuit diagrams of old equipment can be provided. This only relates to "BBC Coded Equipment" that was designed in-house (mainly by Designs Department) and the Terms & Conditions are given below. The information will be provided on PDF files, in response to requests regarding individual items. If possible, the Equipment Code should be given (e.g. AM7/11). This web site has all of the EDI Sheets that were produced and RD&CE listings, so this might help in identifying specific items of equipment. It is likely that most requests will emerge as a result of ex-BBC coded equipment being acquired and this probably doesn't happen very often, but we need to make sure that the BBC is not inundated so please send such requests to me for the time being. Terms & Conditions: "Any intellectual property rights in these [circuit diagrams] are owned/licensed by the BBC. They are made available for private study use only and on the understanding that no warranties are provided by the BBC (in relation to third party intellectual property rights or otherwise) and that all liabilities relating to the individual's use of this material rest with the individual and not with the BBC".
29-Jan-07 15-Feb-07	Who is she? *Resolved*	Andrew Dart would like to know the name of the young lady in the attached photo. Her picture appeared as a single frame in the leader of many films in the 1970's and earlier, and apparently she was well known to the engineers of the BBC. Click to see a larger picture. As a result of the notice above, help came from two people: Richard Russell: I can't tell you the lady's name but this is the famous BBC 61A "Flesh Tone Reference Chart" described in great detail here: http://downloads.bbc.co.uk/rd/pubs/reports/1977-20.pdf and still available from Image Engineering in Germany: http://digitalkamera.image-engineering.de/article.php/Testcharts Dave Buckley (TV Training 1969 - 1993): Lynn, the young lady on the make-up chart, was a secretary in TV Training Department during the 1970's. TV Training was then based at Woodstock Grove and there is an article about it in the July 78 edition of BBC Engineering (page 5). Subsequently it was the first department to move to the Elstree Centre. Lynn came third in a Miss Great Britain contest shown on TV and this may have been the way she got the job of posing for the chart (which must have come in to use around 1976/77 at the earliest).
20-Mar-06 23-Jan-07	LSU/10 loudspeakers *Resolved*	Tom Goulet is seeking information or the Technical Instruction on LSU/10 loudspeakers as shown in the pictures below (click to enlarge). He is specifically interested in the Pamphonics drivers the BBC used in them. As a result of the notice above, help came from David Birt: I have managed to track down D.E.L.Shorter's paper "Loudspeaker Cabinet Design" which I remembered seeing, and had (wrongly) thought had appeared as a BBC monograph. In fact it was published in two parts in the November and December 1950 issues of 'Wireless World". Moreover, I have managed to acquire originals and copy the relevant pages for you. Somehow the words 'research' and 'amplifier' had become connected in my mind concerning the integral amplifier housed in the cabinet. The name Leak also lurked in the background. All can now be revealed! Some LSU/10s did incorporate a Leak "0.1" amplifier (in its first and best incarnation using KT66 output valves). Fortuitously, this is confirmed by a Leak advert. in the same issue of Wireless World which shows a photo of an LSU/10 cabinet with the side cover removed to expose the amplifier. So where does the word 'research' fit in? It was not actually BBC research but the GEC research labs in Wembley. That is where the prototype amplifier was designed, and Leak were employed by GEC as a wiring-shop to build a batch. Subsequently a deal was struck whereby H.J.Leak marketed a simplified design as their own "0.1" amplifier. Thus early LSU/10s may have had a mixture of the original 'research' amplifier and then the subsequent commercial Leak amplifier. Shorter's article (along with many others of that period of Wireless World history) makes fascinating reading. He points out that to apply resistive acoustic damping, you have to position the damping material at a point of high air velocity, and that it is a complete waste of time gluing felt to the cabinet walls which are nodes. I recall that Hugh Britten took note of the physics in his design of enclosures for the GEC metal cone loudspeaker. Since then, enclosure designers have largely ignored the laws of physics, and persisted in putting damping on the walls of the cabinet! It is amazing how often art, craft, and science is forgotten; only to re-discovered decades later! Oh yes! BBC Equipment Department get a mention for building the cabinets which were in two parts, with the carpet-felt damping material stretched across an interconnecting aperture. (That's how 'carpet' got retained in my memory). The cabinets could be puchased from Lockwood. So there you have it! Further information from Richard Carruthers: "David Birt's response to Tom Goulet's post is interesting. I am not sure where the Pamphonic amplifier crept into the equation but I have heard this before; Pamphonic made quite nice domestic equipment but it was not up to the fidelity standard required by the BBC. What I found particularly interesting was the genesis of the "Point One" which I had always thought to be a Harold Leak original. The GEC involvement is consistent with the DSIR not being able to measure the harmonic distortion to the degree of accuracy claimed by Leak when the equipment was launched on the market! Another fallacy, this one much more widespread, is that the LSU/10 and earlier monitors were fitted with Tannoy drivers. As far as I have been able to determine, this never was the case. Mr Shorter's LSU/10 was the last of that particular line which started before the war as the LSU/1 with a Wharfedale driver. Subsequent variants of this early bass reflex cabinet were fitted with Rice Kellogg units which, in turn, were supplanted in the early 'fifties by a Parmeko dual concentric driver, known within the BBC as the LS/1 drive unit. This had a 3" diameter voice coil and 1,75" aluminium horn loaded dome tweeter with crossover at 1200Hz. This arrangement, adopted in 1952, was a bit thin in the mid range supposedly due to problems integrating the horn with the large woofer; nor was it wonderful at the top end - a characteristic not much in evidence before Decca's FFRR revealed all sorts of audio shortcomings. Additionally, noise generated by the 405-line television manifested itself at a bit over 10kHz and occasionally this would find its way into radio broadcasting. Since the Parmeko unit dropped off fairly rapidly after 7,5kHz, this interference could not readily be detected in the studio so it sailed off blithely into the ether. Since it was all AM in those days, I don't suppose many people noticed but the Beeb was always a stickler for quality. The HF deficiency of the LS/1 was disguised by the fitting of a Lorenz tweeter, often bolted to the expanded metal front grille! The LSU/10 was pensioned off in 1962 and superseded by the LS5/1 - a horse of very different colour having a 15" Plessey and two GEC plastic dome tweeters. That Tannoy Dual Concentric drivers were never fitted in this application is something I find a little strange, given that the Tannoy was streets ahead of anything comparable and the driver of worldwide choice for just about every quality monitoring system. Perhaps there was a political element to this as Jack Houlgate had left Tannoy to work for D E L Shorter in R&D. May I conclude by asking if anyone knows how I might obtain a copy of Edward Pawley's "BBC Engineering 1922-1972". Email (via martin Ellen)
20-Mar-06 9-Jan-07	405-line sync pulse generator *Resolved*	David Dunmall (SCPD engineer until 1992) is seeking information about a one-off 405-line sync pulse generator as shown in the pictures below (click to enlarge). It is believed to have been used to drive a breakdown caption generator at North Hessary Tor. "MWA SPG" is etched on the circuit board, which suggests that someone with the initials MWA may have been involved. As a result of the notice above, help came from Maurice Lovelock who identified the designer as Mike Axford. Then, after help from Phil Marrison and BT Directory Enquiries, David had a very interesting chat with Mike and learnt the history of the SPG. David commented that "It is so professionally built that I had previously thought that it was a Designs Dept. prototype that was never put into production".
30-Mar-06	Start Point: U-boat batteries Expired	In the 1950's Start Point had a roomful of submarine batteries to stay on air for 40 seconds in case of a power failure whilst starter cartridges were used to activate the standby generator. There was a wall plaque stating these batteries had been salvaged from a U-boat that had gone aground there in 1942 and that they were manufactured by Siemens. If you can provide any more information about these batteries please contact Anne-Marie Davies. In particular she would like confirmation that they were manufactured by Siemens, because www.uboat.net states that Uboat batteries were all made by AFA.
20-Mar-06	Tacolneston Expired	Hadrian Jeffs is writing a book and contributing to a television programme on BBC Look East to celebrate the 50th anniversary of Tacolneston transmitting station in Norfolk, England. Please contact him if you have any interesting information or anecdotes that would be suitable for publication. He would like an account of an average day’s transmitting routine in the 1960’s or 70’s (although not too technical as he is aiming for a fairly general audience), as well as what it’s like to go up the tallest structure in Norfolk.