Feedback: your letters

E&T hosts a forum for your letters; this issue looks at the arguably flawed switch-over strategy from analogue to digital radio, recovering aircraft black boxes, electric London cabs - circa 19th century, and Senster watch has an update. 

A question of coverage

The British Government is considering a change to broadcasting frequencies that is ill advised. The proposal is to improve the coverage of DAB services on Band III for the national networks and local radio so that the present services on Band II FM can be closed down in six years' time to make way for micro local FM stations.

Quite apart from approximately 150 million owners of FM receivers who may not like this, it is a waste of a valuable frequency resource. Bands II and III are very good frequencies to give large coverage areas that do not need relay stations and for portable receivers inside houses. Band II is currently a wise choice of frequency for analogue FM national networks and for the same reasons could be a wise choice for future single-frequency digital national networks.

According to the BBC, approximately 20 per cent of radio listening is in cars, the majority of which do not have DAB. Micro-service areas will require a lot of manual retuning, which has its own dangers.

The national networks cover most of England, Wales and Scotland using about 30 high-power stations. The BBC provides a large number of relay stations that improve and duplicate coverage very well, but which are not considered necessary by Classic FM. For comparison, the UHF television networks use twice as many high-power stations and over a thousand relay stations to provide 99 per cent coverage for roof-mounted aerials.

Local stations on Band II provide a good coverage for the local area and a much bigger area of patchy reception which prevents re-use of the frequency. Where I live, I can easily listen (on a portable radio with a whip aerial) to local radio stations on the south coast 70 miles away.

There are ways of radiating digital signals to existing DAB radios to give much more precisely defined coverage and closer re-use of frequencies. This is the way forward for local and micro local broadcasting if it proves popular.

It looks like the switch to digital radio will use less expertise and more public debate than any previous technical broadcasting decision.

Kristen J Cadman CEng MIET, Marlow, Buckinghamshire

Outsourcing's upside

I wholly disagree with Martin Gilbert's view that "outsourcing is a euphemism for destroying the manufacturing base" of the UK (Letters, Vol 4 #13). The picture of a closed factory and Mr Gilbert's argument remind me of the stance of the trade union leaders when companies went for automation for improved performance.

Many renowned manufacturing companies have vanished not because of outsourcing but due to dereliction of duties of the management and greed for bonuses. Outsourcing helps to do the mundane work for the engineers who can then concentrate on the complex aspects of the extant problem and plan ahead for the future.

In a competitive world, cost must be reduced to gain wider market. Outsourcing will help the British industry to achieve that. Like opposition to automation in the past, criticism of outsourcing has been a fashionable noise for the nationalists that will do more harm to British industry than good.

Sunil Kumar Pal, London


I must own up to being an inveterate supporter of vertical integration, of adding maximum value and maintaining in-house control of key processes. However, I have some experience which runs contrary to my natural instinct.

In the manufacture of a pressure sensor for hydrostatic measurement of tank contents, the printed circuit board might be 35 per cent of the total cost. Outsourcing of the PCB to, say, China, could result in significant savings, reducing the overall product cost by 20 per cent, thus giving the opportunity for more competitive pricing and higher volumes. This in turn gives rise to higher in-house production rates of the housings, assembly and calibration. The result was an increase of volume and in-house work.

An example of this principle was the decision by Dyson to outsource assembly to the Far East. The consequent economies and opportunity for keen pricing resulted in an increase in volumes and the employment in the UK of a substantial number of additional engineers.

John Welch CEng MIET, Slaugham, West Sussex

Recovering black boxes

'Lightning Reactions' (Vol 4 #13) discusses aircraft black boxes and the inability of authorities to recover them following incidents such as the crash of Flight AF 447 due to the depth of the wreckage.

The argument of increasing the flight data recorder sonar beacon battery life from 30 days to 90 days detracts from the capability of locating and retrieving the device. If it is such that the device cannot be physically retrieved within the beacon operating life then the information that it contains must be retrieved by some other means. Ejecting the device is fraught with complications.

In these technologically advanced years there should be no reason why the FDR cannot be interrogated by surface, or even underwater, vessels and the contents retrieved by water communications and data links. Submarines are capable of underwater communication, so why not FDRs?

Andrew Lavey MIET, Nuneaton, Warwickshire

Tracing Senster

Arthur Moore (Letters, Vol 4, #13) enquires about what happened to the robot that was exhibited at the Evoluon in Eindhoven during the 1970s. The robot, called the Senster, was designed by Edward Ihnatowicz.

The best resource is the excellent website edited by Alex Zivanovic at [new window]. I'm afraid that the Senster has not been preserved, at least not as a complete working sculpture. Zivanovic writes: "The Senster was dismantled in 1974. I thought for a long time that it was completely destroyed but thanks to Erik Frenks, we now know that parts of it have survived. It appears that the electronic components were given away to local electronics enthusiasts but the mechanical structure was given to an engineering company who became aware of the historical significance of the Senster and put it up as an outdoor sculpture next to their building and there it still stands today (2003)."

My own interest in the Senster is that it was controlled by a Honeywell DDP-416 computer (badged as a Philips P9201). I collect these Honeywell minicomputers. Source code for the Senster control program can be found on my website at [new window].

Adrian Wise, Bracknell

Lift safety

Lifts may have a good safety record ('Safer Than Houses', Vol 4 #13), but they have an Achilles' Heel that is probably only permitted by virtue of grandfather rights.

If lifts had just been invented, they would almost certainly be required to have adequate means of escape. On those rare occasions when fire breaks out in a building with lifts and immobilises them, there is little hope for any occupants.

Common sense requirements would be folding steps leading to a roof hatch and similar steps in the shaft leading to the nearest doors. Obviously, opening the hatch would have to immobilise the lift until reset by technicians, an alarm would have to be automatically given and other refinements added. It won't happen, however, until after the next big tragedy, if then.

JR Batts, Banbury, Oxon

London's electric fleet

Opinion seems to be equally divided between the belief that electric vehicles are either going to be the saviour of the ecosystem or they are so impractical they won't function with any degree of usefulness.

Readers might be interested to learn that the current move to establishing an electric cab fleet in London is not a new concept. The first electric cabs, operated in London from 19 August 1897, were called 'Humming Birds' because they ran so quietly and were considered a hazard as neither people nor horses could hear them.

The London Electric Cab Co, located in Lambeth between November 1896 and August 1899, constructed these vehicles. The company was liquidated in 1899 and its fleet seems to have disappeared over time until most people have forgotten that it ever existed.

The London Electric Cab Co was the successor to the Ward Electrical Car Co of London, founded by Radcliff Ward. In 1896 they received the capital to form a bus/cab syndicate and later became the London Electric Omnibus Co.

The electric cab has played a vital part in the development of the transport system in Victorian London - not what one would have expected.

Dan Little MIET, by email


Tim Watkins (Letters, Vol 4, #13) claims that Tesla's London dealership is "an electric vehicles first for London and for Europe". Modec, the Coventry-based manufacturer of electric commercial vehicles, has had six dealerships in London for over two years, a Netherlands dealership since late 2007, and now also has dealerships in Northern Ireland and France, with others planned worldwide.

Iain Cunningham MIET, Coventry

CCD research

The charge-coupled-devices described in 'The Latent Imager' (Vol 4, #14) brought back memories of the 1980s, when I attended the AGM of the Popov Society - the most prestigious of engineering societies of what was then the Soviet Union - in the opulent surroundings of the Officers' Club of the Red Army in Moscow.

During an open question and answer session with the cream of Soviet-engineering, a guy from Texas Instruments asked, "What is the current state of research in the Soviet Union on charge-coupled devices?". This threw the panel into chaos before an international audience which watched them writhe and struggle. With paranoia? With state-secrets? Engineers all, we knew, as they knew, this was absurd.

Finally a spokesman came up with: "No research is currently being done in the Soviet Union." Whereupon this irrepressible guy from Texas Instruments stood up again with: "I find it astonishing that no work is being carried-out in a country of the size and importance of the Soviet Union, on so manifestly important a subject." And sat down.

The following morning a large black limousine arrived at his hotel, and took him to all the research institutes in Moscow working on this subject.

C Reginald Russell FIET, by email

Whose pixels?

Mark Williamson comments in 'The Latent Imager' that the term 'pixel' was coined in the USA in the mid-1960s from a truncation of 'picture element', but notes that its "detailed etymology is unclear". Most technical dictionaries give the same definition, but without the proviso.

I believe that it is erroneous on two counts. I clearly remember visiting Standard Telecommunications Laboratories in Harlow in the early 1960s, where an engineer working in the then new field of on-screen character generation introduced me to the term which, he said, was derived from 'picture cell'. This makes much more sense than picture element, which would surely have been truncated to the much more etymologically-satisfactory 'pictel'.

Can anyone verify this? Should they find it they will have the rare pleasure of not only being able to offer a correction to the Oxford English Dictionary, Wikipedia and many others, but to also define it as "of British origin".

Colin Davis CEng MIET, Gosfield, Essex

Isle of Man

Vitali Vitaliev's After All column 'Engineer's Guide to Tax Havens' (Vol 4, #13) contains some incorrect information about the Isle of Man. Breath tests are legal, seat belts are compulsory and there are mandatory speed limits in nearly all towns and villages. However, when you pass a derestricted road sign, usually in the countryside, there is no maximum speed limit. Using a mobile phone while driving was made illegal here many years before the UK, and new drivers are restricted to 60mph after passing their test for at least one year.

Chris Calvert MIET, Isle of Man

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