Feedback: your letters

So what do E&T readers have to say for themselves this week? Cars effected by radio interference, educating power consumers and studying the 'classics' enjoy a renaissance.

When cars and radio don't mix

It is very disconcerting, when, from no fault of your own or your car, it won't start. We visit a relative who lives nearby about once a week and have done so for a long time. For the last five years we have made this journey in our current car, a Rover 25, although as we subsequently discovered, the make is irrelevant.

This week, when intending to return home, on turning the key to start all we got was a 'nee-naw' noise from the dashboard with lots of warning lights illuminated. We phoned the RAC fearing that something serious had gone wrong with the engine management. A very helpful patrol man eventually arrived from Wigan and was able to park his large van right alongside our car. In the meantime, we had discovered that the central locking did not work.

We gave him the key and he immediately demonstrated that it did work and started the engine. His instruction then was don't switch off, drive home and he would follow us. At home everything worked perfectly.

He then explained that the problem was radio interference, it affects all makes of car, and that it was particularly bad on the top of a multi-storey car park in Wigan where the solution was to push cars down to the lower floors. He had a gadget for checking key fobs and explained that in some places the green light showing a signal would light when there were no keys in the vicinity. His explanation for being able to start our car immediately was that his van had screened us from the interference.

As roadside patrols seem to be well aware of this problem, I assume car industry insiders are also and perhaps they could explain where the interference is coming from and what is being done to solve this problem.

Some advice on what to do if this occurs again would also be welcome - is there a substitute for driving a large van alongside your car - perhaps a piece of sheet metal or a roll of chicken wire in the boot?

Philip Quayle, Preston, Lancashire

Style or substance?

Your article discussing the work of Philippe Starck ('The Art of Avoiding Lemons', Vol 4 #16) confirms that there are 'designers' producing products that don't really work, or at the least, aren't any better than prior products doing the intended job. I expect that they are getting pretty rich on it. What does this say about these people and about consumers?

To my mind, these people aren't really designers at all. Twenty years ago we would have called them 'stylists'. Children are sucked into this misnaming early on, conned into believing that a 'designer product' is something special, whereas almost everything made by humanity is designed, the result of someone's thought process. My teenage daughter and her friends looked very carefully at the designer shirt that one of their rich contemporaries had bought, and had to agree that it was a waste of £90 as it neither looked nor functioned better than a £5 alternative.

Brian Hannam, Basingstoke

People power

'Power to the People' (Vol 4 #18) describes how combining smart meters with home display units helps consumers to control their energy consumption.

Last year I conducted a survey on 'How to save energy if we only knew how' in conjunction with Scottish and Southern Energy and display manufacturer Current Cost. Over 100 premises were visited and some 75 Current Cost monitors fitted. The occupiers, from various groups, were asked to record all items of electrical equipment and to take note of their recorded consumption, before installation and after.

I found that pensioners were already taking steps to minimise their consumption and in some instants leaving a number of rooms unheated. Working families with children found it very difficult to educate their children to switch off appliances and lights when not in use, even to leaving their bedroom windows open.

It emerged that consumers were not aware of the cost of leaving multiple lighting on when a room is unoccupied. People on social security do not seem to be concerned because the State 'picks up the tab'. The display unit must be designed to encourage people to want to look at it. Showing 'weather' and 'temperature' is one possible solution.

Two questions need to be asked. First, how often will the information be seen to be useful or contributing to a users daily routine and how do you get people to regularly use this information? Second, how do you educate people who think nothing of driving their cars a short distance at around 15p per mile, when alternatives such as walking are much cheaper? A tank full of fuel buys a lot of energy for the home.

The exercise proved that it is not difficult to save energy once you know how.

David Le Clercq MIET, Bournemouth

What I personally 'really, really' want is a cheap home energy meter that allows me to, for instance, monitor the day-to-day and week-by-week consumption of devices that turn themselves on and off, such as washers, dryers, freezers and immersion heaters, as I know from the nameplate/IB what the instantaneous consumption should be. For instance, I have no means of checking whether my freezer is working as efficiently as it should do.

Brin Hodge MIET, Wokingham

High grades lose appeal

Dominic Lenton makes several interesting points in 'Making the grade' (Vol 4 #16) about why students seem to be switching back to the traditional science subjects at school. He concludes by suggesting that it may be because we are doing a better job about the public perception of science and engineering.

My feeling is that while presentation is always important it is not driving this change. Teenagers are fickle and maybe the smart ones realise that record-breaking grades and numbers are good for their school and government but not much use to them, especially when their currency is devalued. There is not much point being the same among many with wonderful grades that employers see as easy options.

Perhaps the smart ones have realised that they can stand above the rest with the traditional and respected qualifications so are choosing harder subjects that will pay dividends.

Ben Mason CEng FIET, Kolossi, Cyprus

Early magnetic recording

EurIng TRH Sizer (Letters, Vol 4 # 17) asks about the early development of magnetic recording. There is an excellent history of post-World War Two tape recording on Wikipedia (under 'reel to reel') which refers to the American effort started by Jack Mullin and Colonel Ranger of the US Signal Corps at the end of the war. I don't know how the British work began but I was at EMI in 1950 in Dr GF Dutton's Engineering Development Dept where the work was well advanced on the BBC's BTR 1 and 2.

We were designing an over-the-shoulder recorder to be used by correspondents going to the 1952 Olympic Games in Oslo. We delivered a few very expensive hand-made models in time for this event. However we later received a report that one of these had gone overboard when the shoulder strap clip gave way.

Tape was not new to the BBC. They had been using the Marconi-Stille recorder for Empire Service repeats and delays since 1933. The steel tape ran at about 50 ips so the reels were very large and it used DC bias. The great invention of the Magnetophon was to use high-frequency AC bias and dispersed iron oxide on a plastic tape. We measured 60 dB S/N below a peak level of 3 per cent total distortion at 1Hz which was at least 10dB to 20dB better than any other system at the time.

The broadcast industry standardised on 30ips instead of the slightly higher metric speed of the German machine because their lager capstans could be ground down to fit the imperial inches rather than the other way around.

John L Mack, Laguna Beach

Thick or thin

Your report 'Arctic survey data confirms rapid ice loss' (Vol 4 #18) gives credence to an expedition that has been debunked in parts of the scientific media. It has been PR not science from the start using the BBC as its main outlet to broadcast regular messages to the world. The results had to confirm what they had already concluded - ice is disappearing fast with catastrophic results for the northern hemisphere. The whole exercise was to go out in the glare of publicity and bring back some data that would prove them to be right.

The expedition never reached the north pole as it planned because of the unexpectedly severe cold weather, which also rendered their ice radar sounding equipment useless. Hence they had to resort to drilling holes and use a tape measure. Nevertheless, they came back with the results they wanted, which was the whole point of the exercise.

Another data source of Arctic ice thickness in 2009 came in the form of an aerial survey using a towed radar array from the Alfred Wegener Institute for Polar and Marine research in Bremahaven. They didn't have to risk lives, create drama or bleat constant headlines to the BBC while doing the science; they simply flew the plane over the ice a few times. Their conclusion? At the North Pole the ice sheet is thicker than expected!

John Thompson CEng MIET, Coventry

[Nick Smith responds to comments prompted by his story in 'If You Ask Me' on page 16.]

Bright ideas

The letter from John Harrison on recharging primary batteries (Vol 4 #16 ) reminded me of my own experiments in the 1950s. I was apprenticed to a Nottingham firm of telecommunication engineers and cycled to work and to night school, and trained for my chosen sport of cycle racing.

In winter, the cost of replacement batteries for the conventional twin-cell cycle lamp was, for an apprentice, considerable, and I employed a system of recharging using a half wave rectifier, with a small discharge current via a bleed resistor during the other half cycle. Although the recharged battery life was less than that of a new battery, the initial terminal voltage was slightly higher, and I was able to repeat the procedure for many cycles, degradation of the zinc casing probably being a limiting factor. I believe my call-up for National Service terminated the procedure.

Ray Booty CEng MIET, Allestree, Derby

John Harrison describes a couple of interesting ways of recharging 'dry cells', without giving away too many secrets. Does no-one remember the 'dirty DC' method that was so popular many years ago? All you have to do is connect the dry cell to a low voltage AC supply via a single-phase rectifier across which you have connected a suitable resistor. Don't ask me what value resistor!

Stuart Bridgman CEng MIET, Wellington, New Zealand

New routes

John Norbury (Letters, Vol 4 #18) suggests some route possibilities consequent upon the introduction of new buses into central London. While I can see the logic of introducing terminal interchange points for suburban routes, I can also foresee problems since some passengers do not wish to make changes, if avoidable. This is a problem that current rail planners have failed to realise with their breakdown of cross-country routes into individual sectors in order to avoid delays rather than tackling the causes of those delays.

I certainly appreciated the service that took me from Euston out to Hammersmith Broadway avoiding the heat and congestion of the tube.

Alan D Crowhurst, Cleobury Mortimer, Shropshire


The article 'Sounds of History' in the 24 October 2009 issue of E&T included the sentence: "The underlying principles of pulse code modification were the brainchild of telecommunications engineer Alec Reeves, who developed the concept to reduce interference on analogue telephone calls." This should, of course, have read "pulse code modulation".

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