Transmitter shipments

 

 

Short Wave

 

This list was provided by Chris Gardiner and can be found here.  The following notes apply:

 

One transmitter not built was the B6125.  This was the first 500kW transmitter designed by Marconi’s.  It was a conventional (at the time) class C RF output stage with a class B push pull modulator.  This would have been around 1980.  However, events were moving very fast at that time with regard to efforts to improve overall efficiency and the B6125 RF stage was married to a switching modulator and became the B6127 but with the modulator still essentially coupled to the RF in the manner of the Class B modulator.  This was then rapidly overtaken by the advent of SSB for broadcasting and to do this dc coupling between modulator and RF stage was needed.  This was implemented by having the RF and modulator switching valve in series across the HT supply and became the B6128.  In terms of basic design the B6128, B6126 and B6131 are the same.

 

In the list above the only conflict is that the BD272 of the early sixties became the B6122.  It is possible that the BD274 is the same as the B6123; I have no knowledge of the BD274 but I know the BD253 and B6123 are different.

 

 

Medium and Long Wave

 

This list was provided by Chris Gardiner and can be found here.  The following notes apply:

 

Where the list says paralleled transmitters this does not necessarily mean a pair.  I seem to remember that somewhere in the Middle East there were three x B6026 giving 2.25MW carrier, I think this was the 1967 Kuwait order.  The transmitters were destroyed in the first gulf war of 1990 and although I saw the remains in 1991 it was impossible to tell how they had been configured.  Where you see one transmitter marked as parallel this will be because another was sold later to make the pair – see Abu Dhabi 1973 and 1976.  Also, the 50kW B6034 was sold as parallel pairs, parallel triples and parallel quads.  This was done at the BBC’s request so they had four power levels but only one set of spares and small output valves.  It could be argued that they needed more output valves with this arrangement but this transmitter was particularly gentle on its valves and it was not unknown for the output valve to last in excess of 50,000 hours.

 

The Yemen order of 1988 was also a quad parallel with the system in four containers, two 40 foot each containing two transmitters with a third open-sided that fitted between the other two to produce a transmitter hall and the 4-way combiner was fitted into a separate 30 foot container which also housed a 2-way combiner.  I never saw the final installation in Yemen but I believe that after a year or two with the parallel quad the system was broken up and run as two single transmitters and a parallel pair, hence the original order included the two-way parallel.  It was at about this time that North Yemen (Sanaa) and South Yemen (Aden) became one country so the need to blast a 200kW signal from Sanaa down to Aden disappeared and post reunification one of the transmitters certainly ended up down in the south at Mukalla.

 

Note that the B6046 (1986) is in fact a B6034 modified for long wave.  The reason the power is reduced is because the antenna VSWR at ± 4.5kHz on the carrier is so great.  Into a resistive dummy load the transmitter will produce 50kW.  Others may be able to confirm but I believe that one of our 50kW dummy loads at New Street was modified during lab tests to simulate the long wave antenna.

 

 

Note

 

Prior to receiving the shipment lists above a work-in-progress listing of Marconi Broadcast Transmitter shipments was being worked on and can be found here.  This will be retained in the short term for reference.

 

 

General customers

 

Click here for details - primarily photographs

 

 

Isle of Wight Radio

 

Neil Friday has kindly provided the following information on the establishment of the Isle of Wight Radio Station which was launched on Easter Sunday 15^th April 1990.  At that time he was its Chief Engineer. 

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In 1897, Gugliemo Marconi made a break-through which changed the world.  He established the first ever, permanent wireless station high on the cliffs above the Needles.  Over the next 30 years working from the Island, he made immense discoveries opening up the enormous potential of radio broadcasting.  Nearly 100 years later, Isle of Wight Radio is here to exploit that potential and make full use of Marconi's brilliant discoveries.  With such a pioneering background, Isle of Wight Radio will be dedicated to providing its listeners with a quality of programming never heard before in Local Radio.  Like Marconi, Isle of Wight Radio will offer ingenuity and originality, presenting new ideas in a fresh style and ensuring Islanders will have a new landmark to boast of.  Isle of Wight Radio will offer a new beginning of independence for the Island and bring Marconi's discovery back to the place it belongs.

 

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The following links can be viewed:

 

1. The Souvenir Programme Launch Issue available here
2. The audio copy of the first radio programme from Isle of Wight Radio is available here – a YouTube link
3. Reminiscences of setting up and running of the station available here

 

Rugby Radio Station

 

Wilf Roberts has kindly provided this YouTube link to a vintage Pathe film about the original Marconi installation at Rugby – regarded then, in 1932, the world's greatest radio station.

 

The various shots include; the huge telegraph masts supporting the main aerials (we go up and down one of the masts in a lift), the machinery and generating equipment inside the Wireless Station, a transmitter is seen sending out a message in Morse code, saying that Rugby Wireless Station is the most powerful in the world, blinking lamps assist in the sending of messages, and the huge tuning coils.

 

 

Dubai Radio and Colour Television (DRTC)

 

Installed in 1976 DRTC required a television relay transmitter to be installed at the top of a mountain to increase coverage.  Mike Baker provided the photographs and Peter Farnworth the copy.  Click here for details.

 

 

 

Large accounts

 

Please note that the DOWNLOAD tab has to be pressed when Project Plan summaries are selected.

 

 

The Voice of America - Botswana, Morocco, Sri Lanka and Thailand

 

The VOA contract was probably the largest broadcast order ever placed and was won after an evaluation of world suppliers by installing four transmitters in Greenville, North Carolina (there is a video on YouTube here of a tour of VOA Greenville showing the various transmitters installed there.  The B6128 starts at 5 minutes 16 secs).   One from Continental Electronics ( US ); one from Brown Boveri ( Swiss ); one from AEG Telefunken ( German ) and one from Marconi.  These were evaluated for a year prior to the main order being placed in 1988.

 

The original contract was for Marconi to provide 50 off B6128 500Kw HF Transmitters.  However, when President Clinton came into power this order was reduced to 21 units to be assembled in Cincinnati, for local content, from parts provided by Marconi at Chelmsford.  The allocation of these was to be 10 for Morocco, 7 for Thailand and 4 for Sri Lanka.  It is recollected that a single B6043 600Kw MW Transmitter was manufactured in Chelmsford and shipped to Botswana in Africa.

 

As at May 2013 the following Marconi-supplied stations were still operational: Botswana, Sri Lanka and Thailand.

 

Site photographs are available here.

 

Derren Felgate, who was on the original installation team in 1994, visited the Station whilst on holiday in 2016 and took these photographs.  He later added by email:  "The other person in the photos is Adisak Pattanajakr, is now the Station Manager, and was one of the original technicians we trained at the time of installing the site.

Phaitoon, although retired, has had his contract extended and looks after all the switch matrix and dummy loads.

As far as I am aware, this site is the last Marconi installation still running from the VOA contract. They have all the usable parts from both Sri Lanka and Morocco sites to keep running. Tx 6 & 7 are still in the original condition whereas Tx 1 thru to 5 have been modified for digital broadcast and are now running far more efficiently".

 

The project plan summaries are available here. 

 

 

Ministry of Information - Kuwait

 

Site photographs are available here.

 

 

Radio Republik Indonesia

 

The project plan summaries are available here.

 

Description provided by Andy Reed - September 2013

 

There were two projects in Indonesia for RRI. One for the domestic HF service and one for international.  The domestic service had two sites; one at Cimmangis near Jakarta and one at Ujung Pangang each fired back towards the other to cover the whole of Indonesia with a single programme for the first time. International services were added later at Cimmangis . I can’t recall the exact target areas but I think it was to provide coverage to the Mid East, South America, the east coast of the USA and I think Japan.

 

Each site used 250kW transmitters, 300 ohm switch matrix, R9010 curtain antennas and self supporting towers. Equipment was installed in existing buildings. While generally welcomed, there was opposition to the potential loss of the Cimmangis football pitch to accommodate one of the antennas. Local residents were so keen on the project they actually stole all of the copper conductors from the bayfeeder of one antenna; fortunately for them it wasn’t operational at the time.

Bidding and the negotiation of contracts was a long drawn out affair. Dick Baker led the high level negotiations with the detail being left in the hands of John Rolfe (transmitters), Andy Reed (antennas) and Robert Shales (commercial). Tony Barber also made occasional visits and John Mason was there as well for a while. In the days before the wide use of mobile phones, much of the time during our frequent visits to Jakarta was spent waiting for phone calls in the hotel rooms or around the pool at the Mandarin. They were long days with breakfast meetings with the Agent and calls from Chelmsford through to midnight For final contract negotiations we hired several rooms at a beach resort hotel where the three of us spent days convincing the clients’ team of (12+?) of the benefits of the Marconi solution. I do remember spending an inordinate amount of time (at Chris Bragg’s request) in trying to get them to include a telehandler in the erection gear that they were buying . 

 

 

 

 

ERTU ABIS Transmitter Station - Alexandria, Egypt

 

The project plan summary is available here.

 

Comments on the Project Plan Summary by Chris Gardiner - August 2013

 

Yes this is the same contract, but that is a document I have never seen before although the basic details are correct.  It’s odd that the price is quoted in US$ as the contract if I remember was in sterling.  I don’t think I have a copy of the commercial offer but I think the quoted price was around £1.3M

 

All my bid documents are dated January 1995 so the timescale is likely to be order in 1995/1996 and contract effective in 1996/1997 when the ILOC came through the bank.  It might have been a bit quicker because the transmitter was delivered and spent some time in store at ABIS before installation commenced in 1998.  Normally these large transmitters take 12 to 18 months to produce.  The problem was that ERTU would not start work on the building modifications until they had the transmitter in their possession, even though they had the installation/building drawings back in 1996.

 

Input from Chris Gardiner – August 2013

 

The transmitter was a B6132 shortwave of 500kW carrier.  We had sold this to ERTU in 1996 but it was not until 1998 that installation commenced.  The installation engineer was John Coleman but he was very much a “mechanical” person and although he got the filaments working he was not prepared to switch on the HT supplies.  I was sent out in June 1998 as the commissioning engineer,  even though I had never commissioned a transmitter before, with the comment “it will only take you about 8 weeks”   I left 13 months later!

 

In fact it only took about 8 weeks to commission; the rest of the time was spent trying to give ERTU staff enough confidence in the transmitter so that they would sign the acceptance certificate.

 

One problem was that all the building modifications were undertaken by ERTU themselves, working to a set of Marconi drawings but without any Marconi supervision.  With the result that many things were not as they should have been.  Inaccurate holes in walls were not too serious, John Coleman could easily modify these, but badly fitting doors on the cooling rooms meant that dusty air was being sucked into the plenum rather than passing through the filters.

 

The transmitter was the prototype B6132 but built to the final drawings so that it was saleable and no different from the later production model.  But when delivered it had modules missing, for example the SSB facility, and this had to be fitted and demonstrated while ERTU staff were watching – not a good idea when they were already uncomfortable with its complexity.

 

 

 

 

Chris Gardiner can be seen in the centre, the Station Manager is second from the right.

 

 

BBC Seychelles - Indian Ocean Relay station

 

The project plan is available here.

 

 

BBC Rampisham, Daventry and Skelton - England

 

Site photographs are available here.

 

The project plan summaries are available here.

 

 

Woofferton transmitting station 

 

Used initially by the BBC for their World Service a suite of YouTube videos is available here which shows much of its history including the commitment to the Marconi company.  Thanks to Martyn Clarke for finding these.

 

70 years on the air - the first HF relay station in the world is still going strong.  Here Dave Porter, G4OYX, one time senior Transmitter Engineer at the site, outlines its history and current status.

 

The Marconi BD272 and B6124 HF transmitters - a video tour, preceded by an introduction to Woofferton transmitting station.  Part 1, 2, 3, 4, 5, 6, 7 (BD272); 8 and 9 (B6124).  Click on the links to view each these videos, which were uploaded to YouTube by the presenter David Porter.

 

 

BBC Droitwich - England

 

A 1935 article is available here, and a 1994 paper entitled "Droitwich Calling" by John F Phillips is available here.

 

Neil Friday has kindly provided additional information relating to the Marconi transmitters at Droitwich including a link to an Avengers episode where the original building can be viewed.  Click here to view.

 

 

BBC Ascension Island 

 

An article describing the BBC at Ascension Island was written by D.A.V. Williams, the BBC project manager, in about 1966 and is available here.

 

Comments by Chris Gardiner - December 2013

 

This paper was published about a year before I arrived on the island and, not surprisingly, shows some very early pictures of the sites. They appear to have been taken ca. 1964 during the construction phase. By the time I arrived in September 1968 there was much more concrete hard standing around the transmitter building and Two Boats village was much larger and better developed. The station on Ascension was very much D A V Williams' pet project and because of his seniority in the BBC made it much easier to get things done on Ascension than it did at UK sites. If you needed something in the UK it was a long drawn out process usually being met with the response "do you really need it?". On Ascension you asked Dave Williams and it arrived on the next plane or ship! Much of the content of this article was published in the BBC's own magazine Ariel but written by someone from the programmes department so had a slightly different emphasis. Sadly, all my pictures taken on the island are on 8mm cine film and I don't have any way of scanning this to produce a few still photos.

 

Further comments:  The answer to your question is nothing apart from the antennas and their switches.  The control desk in the transmitter hall was BBC designed and built and there was a rack that contained the Marconi B6122 synthesisers but in any case they were part of the BD272 transmitters.

 

There was also a 1kW medium wave transmitter that was in a separate building and used for local programmes but this was unattended and I can’t ever remember anyone going in there so have no idea if that was of Marconi manufacture. The MW programme feed came direct from Butt Crater and most of the time carried the green network.  This was then called the General Overseas Service and was the main English service, now called World Service English.  There was a 10 minute opt out on Friday evenings when the local Ascension News was broadcast.

 

Butt Crater was the receiving station, just over the hill from the transmitter site and about 2.5 miles away.  This is now decommissioned as programme feeds are by satellite.  In those days it had Racal RA117 double diversity receivers and Leevers-Rich tape recorders.  There was also a small studio for the local broadcast (see above).  All the programme switching, including the main transmitters was done here at Butt Crater.

 

We installed two further BD272 transmitters in 1989 moving them from Daventry and at the same time built four extra antennas.

 

So far as I know most of the BD272 have now been scrapped and replaced with transmitters from RIZ in Zagreb.

  

 

BBC Overseas Service, Berbera, Somalia

 

The purpose of this transmitting station was to relay the BBC Overseas Service to Arabian countries using two 750Kw Medium Wave transmitters operating in parallel to provide the 1.5 Megawatts of power required.  At that time it was the largest transmitting system Marconi had made and probably remained so to this day.  It was known as “Project Beryl”.

 

This transmitting station was built on a sand bar at Berbera in a country then known as the British Somaliland Protectorate.

 

The system was so large that each 750Kw transmitter could only be assembled and tested at Marconi’s New Street Works one at a time.  This was because of its sheer physical size and the amount of electricity it consumed.  Testing at full power (750Kw) had to be carried out at night when the town’s power consumption was at its lowest.  The full system was never tested prior to shipment.

 

The timescale of Project Beryl was such that the documentation for commissioning the system would not be available in time.  This was clearly a major problem so Wilf Roberts, a senior commissioning Engineer with Marconi, took it upon himself to hand-write a set of notes and diagrams, and provide photographs.  This was a mammoth effort and has been recorded here (large file).

 

 

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