Feedback: your letters
This issue: readers respond to our review of cloning technology.
Amateurs well aware of long-range radio
The experiments with radiowave propagation at 2GHz described in Vol 3 #10 ('Research promises boost for emergency radio communications') do not break new ground. Anomalous tropospheric propagation is a phenomenon well known at frequencies above 50MHz. The relationship to meteorological conditions has been well explained although prediction remains less certain.
As far back as 1963 radio amateurs contributed to an IGY project to study this aspect, using results largely obtained from observations of distant TV transmitters in Band I and also amateur transmissions at 144MHz. Papers by RG Flavell published in the RSGB Bulletin in March 1963 and March 1964 fully describe the physics of the meteorological conditions which give rise to such propagation. A further paper by Newton, published in February 1965, describes the results of the many observations made during the project.
Of recent years, supported by the development of better equipment, there are many recorded instances by radio amateurs of such propagation at frequencies around 1300MHz and there is no reason to suppose that higher frequencies might not be similarly supported, albeit on fewer occasions. The benefits of a sea path in achieving long-range communication due to tropospheric anomalies are well known to today's radio amateurs using frequencies upwards of 144MHz. Temperature inversion and tropospheric ducting are terms well established in their vocabulary.
In 1955 I was, as a fresh graduate, involved with experiments carried out by BBC Research to establish the propagation characteristics across a sea path at UHF. Using a frequency of (if my memory serves) around 650MHz, the received field strength of transmissions from Scheveningen on the Dutch coast were recorded at five sites along the east coast, from Kent in the south right up to Fife.
The results provided valuable input to the planning of the UHF TV transmitter network in Europe which culminated in the 1962 Stockholm Plan. Those results demonstrated the existence of enhanced tropospheric propagation just as described in your article and enabled the planners to minimise the likelihood of co-channel interference for much of the time although for those on the south and east coasts not entirely.
Professor RC Hills FIEE (licensed as G3HRH), Winchester
Cloning: right or wrong?
I am saddened that the usually excellent E&T should include a rant against pro-lifers and the Catholic Church regarding the use of embryos ('Cloning cures', Vol 3, #11). I am a 'pro-lifer' and a Catholic and I take exception to Philip Hunter's disparaging remarks about my views on when human and spiritual life begin.
Many others, of all religions and none, share concerns on ethical grounds about recent developments in embryo research. According to some scientists there is no demonstrable scientific or medical case for creating, without any clear scientific precedent, a wide spectrum of human/non-human hybrid entities or 'human admixed embryos'.
Philip Hunter seems to think that we, the British, have got things right and that the US and EU, and presumably the rest of the world, have got it wrong. I suggest that the real reason that the rest of the world is not so eager to undertake such research is that they are unwilling to follow us into this ethical minefield. Many scientists in these countries are of the opinion that such research is mistaken and misleading and will lead to unrealistic expectations and lack of public confidence.
Edgar Martin CEng MIET, West Wickham, Kent
Philip Hunter's comment that the recent House of Commons vote on embryo research "...preserved the UK's position as one of the world's most liberal regimes" is unfortunate, implying that the utilitarian aspects are all that really matter.
Of course it is important to try to minimise the ravages of Alzheimer's, for instance, and its effects on the patient's dignity, but surely the philosophical, human, and religious issues are far from settled - as even a cursory reading of the recently-released 'Human Dignity and Bioethics' essays of the US Presidnt's Commission on Bioethics will show. Indeed, there is no consensus among the contributors to that volume on precisely how to define human dignity
When the so-called 'slippery slope' to eventual chimeras and human cloning leads to something like Huxley's Central London Hatchery and Conditioning Centre, it will be too late for a rethink. The technologically sweet is so alluring that, as J Robert Oppenheimer reportedly said - albeit in a different, but ethically loaded context, "you go ahead and do it and argue what to do about it only after you have had your technical success". The issue today is no less important than that facing humanity in the post-war era.
Francois Duminy CEng MIET, Pretoria, South Africa
Philip Hunter's interpretation of the 'absurd' Catholic position on embryo research seems to be derived more from Monty Python's 'Every sperm is sacred' than the reality of the church's standpoint. The church teaches that the human embryo must not be used, exploited or destroyed. This is an ethical stance which is not changed just because recent scientific advances have enabled different means to create embryos.
The Catholic Church is singled out as an opponent to this research but this disguises wider unease. In a poll on the British Medical Journal website after the Parliamentary debate, a majority of readers thought that MPs were wrong to allow the creation of human-animal hybrid embryos. In fact, a range of opinion polls show that the majority of the public is against the creation of human-animal hybrid embryos.
The article conceals the fact that the scientific benefits of human/animal hybrid embryonic research are seriously in question. Take for example a letter to The Times signed by a number of scientists and academics which said: "There is no demonstrable scientific or medical case for insisting on creating, without any clear scientific precedent, a wide spectrum of human-non-human hybrid entities or 'human admixed embryos'."
Compare this with the recent exciting advances in adult stem cell treatments which in addition offer a more ethical alternative.
Phil Kershaw IET member, Didcot, Oxfordshire
Not so fast
It is all very well for Ofcom to plan superfast broadband (Vol 3 #11) but what about people like my daughter who lives on the A617 Newark to Mansfield road in Nottinghamshire? She is trying to run a business on a dial-up Internet connection as the BT line is not good enough for broadband. She has investigated a mobile 'dongle' but none of the networks give an adequate signal even though she lives at the top of a hill. The first priority should be to extend the fibre to a satellite box which then feeds by wire to the nearby properties.
Rob Waldron, Bilsthorpe, Notts
William Knight ('More gas than wind', Vol 3 #11) might have referred to the possibility of extending the methane life of old landfill sites by recirculating the leachate through the landfill. I believe SITA has done this at the Packington Estates 6MW generation scheme in the Midlands, as the morphology of the site has changed since it began in the late 1980s.
Brian Mallalieu, Youlgrave, Derbyshire
While I agree with David Laverty's letter in E&T Vol 3 #11 regarding invisibility and cloaking devices, could I just point out that invisibility is not only possible but actually in use. As a member of the St John Ambulance brigade I can vouch for the fact that once you put on the uniform, including the high visibility jacket, you are instantly rendered invisible. I have personally witnessed the surprised looks on the faces of members of the public when you ask them if they need help after they have fallen down right in front of you.
The effect isn't confined to personnel either. On one occasion after an accident, one of our members overheard an incredulous policeman ask the driver who'd just driven into the back of the ambulance: "You mean to tell me you didn't see a large white vehicle with blue and yellow flashing lights!?"
No doubt members of the British Red Cross Society, or indeed anybody who drives an emergency vehicle of some kind, will bear out the fact that the cloaking device is not just confined to the Klingon Battle Cruiser.
Reid Thomas MIET, Cranleigh, Surrey
Keri Allan ('Forging a firm future', Vol 3 #12) should really know that Hurricanes and Spitfires were fighters not bombers. They formed the backbone of Fighter Command for much of the Second World War.
Perhaps if would be good to have an article on these aircraft, why they were so good and what they contributed. While this might be old hat to many older people, the Battle of Britain remains an iconic part of our national heritage, of who we are as a people.
It is interesting to note that at my first airshow I went to a couple of years ago, the only time when everybody stood up was for the arrival of the Battle of Britain Flight. There was a palpable change in mood, completely unorchestrated.
Revd Dr Robin McKenzie, CEng MIET, by email
On the road already
The Acabion car, said to be the world's fastest road vehicle ('Rocket on wheels', Vol 3 #12), seems brilliant. However, it bears a striking similarity to the Monotracer (www.monotracer.com [new window]), also from Switzerland, which is in production and has been around for several years.
David Manners, Gateshead, Tyne & Wear
Who remembers coalene?
Thank you for publishing my letter under the heading 'Into the black' in E&T Vol 3 #10. What I did not know when I wrote it was that oil and petrol from coal called Coalene was being sold by petrol forecourts in 1935. This was revealed in the Mail on Sunday on 15 June. A photograph shows Labour MP Tom Williams filling his Rolls-Royce with Coalene. I was 13 at the time and well remember the wide variety of petrol types on offer, but not this one.
This predated the German wartime efforts. Do any readers know the history of Coalene and why it was discontinued?
Alan E Lott, Reading
Solar returns aren't just financial
Geofffrey White (Letters, 21 June) is unduly pessimistic about the case for solar thermal. In answer to his final question of who would invest in a system knowing that the returns are likely to be low, I can answer "Me, for one!".
I had such a system installed two years ago, partly because I had to renew a hot water system anyway. It is reasonable to offset the cost of other options in arriving at the extra cost of using solar in the case of new build or when renewal is necessary. Also, the rate of VAT quoted by Mr White is incorrect - it was only 5 per cent, even for an installation on an existing building. Overall, the net cost was £3600 net of grant, and I would have had to invest at least £600 whatever I did, so the net cost of the solar option was more like £3000, which gave me a mains pressure system capable of delivering up to 18 litres per minute - a vast improvement on the previous gravity fed arrangement.
Overall, I consider the return to be closer to 3 per cent than 4 per cent at current energy prices (I use off peak electricity for the non-solar portion), which compares well with leaving cash in the bank, although financing it by borrowing would, I agree, be less attractive. One can do more sophiscated investment calculations, to arrive at a net present value based on assumptions about future energy costs; these look much more attractive, particularly if energy prices are expected to rise faster than inflation generally.
Of course, not all investments are made for economic reasons, and it is satisfying to have taken out a reasonable chunk of demand. In the end, there is a feel good factor about it, and I hope a future purchaser of my property might agree.
John Keepin MIET, Swindon
Geoffrey White gives us a well argued costing of domestic solar power. However, as one of the characters in Oscar Wilde's 'Lady Windermere's Fan' said: "A man who knows the price of everything and the value of nothing". The point is not to save money, but to save the planet! If there was money in it there would be no problem; global capitalism would be on the case!
Phil Hingley MIET, London
Back in service?
When I retired from the CEGB 20 years ago about 50 500MW sets provided a large part of the total national load. The dash for gas by the subsequent companies has led to predictable consequences. I imagine that many of these power stations are still in existence on sites connected to the transmission network .Is it a practical suggestion to return these sets to service with their fossil steam raising plant replaced with nuclear fuelled boilers?
HG Hawkes, Bristol
Home energy stores
Given the current debates about local versus national power generation, I have been reading recent discussion about proposed supplier obligations. One proposal under review is to charge an increasing amount as consumption rises. I have been intrigued with the concept of every domestic property having an energy store such as a battery or fuel cell and only drawing from the grid the average domestic consumption and not the peak. Can anyone in the industry with access to appropriate data give an indication of what impact this might have on the our National Grid as I have a feeling it may be very significant?