(See end of table for resolved items)

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

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."

New: 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."

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!"

New: 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."

New: Mark Timlin 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.

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.

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.

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.

He is now looking for an original amplifier.  If you can help then please make contact via the above link.

10-Jan-08

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.

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

Cancelled

Project closed, but see request regarding Cromer dated 3-Dec-07.

26-Sep-07

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

10-Aug-07

Resolved

Information provided via new arrangement with BBC (see next item below).
Further information offered by Mike Davis and Richard Barnes.

10-Aug-07
 

Resolved

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".

15-Feb-07

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).

23-Jan-07

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.

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".

Old and unresolved

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.

Old and unresolved