New digital radio stations and the introduction of DAB+

Digital Radio; photo by Stephen Martin, used under terms of a Creative Commons licenceReaders could be excused for not knowing that a new digital radio multiplex launched in the UK today, containing 18 new stations. There has been little in the way of fanfare; in fact, there has been virtually no media coverage at all. Take-up of DAB radio continues to be poor, thanks mainly to two factors. One is that people don’t see the need for, and are not interested in, the additional stations available. The other is that the sound quality fails to live up to what was promised: better than FM quality.

A quick glance through the list of stations shows that the stations are largely more of the same from the same big commercial broadcasters. More Absolute radio, More Kiss, more “chill” and “smooth” pop music stations. These are hardly going to have people rushing out to buy a DAB set. There are also stations aimed at particular religious or ethnic groups: Muslims, Christians, the Asian community. Surely these are only going to attract a small number of listeners? There is also a children’s station, plus Jazz FM makes a welcome appearance on national terrestrial radio (having only previously been available in London or online).

Sadly, when it comes to sound quality, it’s the same old story we have become familiar with on DAB. Most of the stations are in mono, and have bitrates or 80 kb/s for music, or 64 kb/s at a lower sampling frequency for speech stations. Once again, rock bottom sound quality in order to squeeze in the stations, and that fantastic improvement of stereo FM to mono DAB. There is, however, one interesting new development. Three of the stations are being broadcast in the newer DAB+ format, using the HE-AAC v2 codec (also known as aacPlus). What’s more, these stations are in stereo! Before we get too excited, though, the bad news is that the DAB+ stations are only being broadcast at 32 kb/s. Now, while HE-AAC is much more efficient than the MP2 codec used in old-fashioned DAB, is it really that much more efficient? The people who developed HE-AAC claim 48 kb/s gives similar performance to MP3 at 128 kb/s. But we only have 32 kb/s. Do these new DAB+ stations sound even as good as the few existing 128 kb/s DAB stations such as Classic FM?

A quick listening test immediately shows the answer to be no. Tuning to Jazz FM on its new DAB+ channel, the sound quality leaves a lot to be desired. There is that clear rasping sound, an immediate sign that the audio has been encoded using too low a bitrate. Switching to the 128 kb/s MP3 internet stream, the difference is stark. A much wider soundstage, clearer, deeper, smoother tones, none of the artefacts due to low bitrate. Even if anyone thought the DAB+ version was OK, I would challenge anyone to say they couldn’t hear the difference in the MP3 version.

Turning now to Classic FM on DAB, at 128 kb/s MP2, although the sound is always slightly harsh, it doesn’t have the same raspiness that belies a low bitrate. Switching to internet radio, 128 kb/s MP3, there is still an audible difference, but it is more subtle. The sound is more pleasing to the ear, but it’s harder to place quite why. The conclusion is that 32 kb/s DAB+ does not sound as good as 128 kb/s DAB. But then, it only takes up a quarter of the bandwidth.

It would be interesting to know why Jazz FM chose to go down this route. Were they desperate to broadcast in stereo? Their London broadcast is only mono. Or did they want to save money by going for DAB+, and stereo is just a by-product of that? The argument against switching to DAB+ in the UK is that many people have DAB sets that can not decode DAB+. However, I’ve long doubted that to be significant. Radios sold for a long time now have been DAB+ ready (although some Pure branded sets apparently didn’t actually include the HE-AAC codec to save on licensing fees, making a complicated download process necessary!) Surely only very early adopters, and then only those who have hung on to their by-now rather antiquated DAB sets, wouldn’t be able to pick up the new DAB+ stations? In any case, the naysayers have been proved wrong, and DAB+ has come to national digital radio.

Jazz FM and the other two DAB+ stations should be considered experiments. If they attract a significant number of listeners on DAB+, that should make the case for other stations to swtich to DAB+. The trouble with digital radio is always that these is commercial pressure to squeeze in the stations, and that means poor audio. By switching from DAB, to DAB+, you can have the best of both worlds. An 80 kb/s mono DAB station can become a DAB+ at 56 kb/s – the highest possible bitrate for HE-AAC – providing higher quality, stereo sound in 70% of the bandwidth. That way, it would be possible to improve the sound quality of all of the stations on the original national commercial DAB multiplex, while leaving room for four or five additional stations. Everyone wins except a few people with old DAB radios, and if they are early adopters, they will have enjoyed the original DAB transmissions at 320 kb/s, and will likely have thrown the radio in the cupboard in disgust at the degradation of the service many years ago.

The current choices made for the DAB+ broadcasts are a poor demonstration of the technology, just as squeezing the DAB bitrates have made those stations unpleasant to listen to. Yet if, despite this, DAB+ listener numbers are seen to be on par with DAB, and it results in an industry-wide switch to DAB, something good could yet come of it, and the UK may eventually have digital radio broadcasts that live up to their original promise.

Aristocratic titles that shaped physics teminology

William Cavendish, 7th Duke of Devonshire (public domain)

The 7th Duke of Devonshire

I recently read that the buildings of the old Cavendish Laboratory at Cambridge University are under threat of partial demolition, which led me to consider where the laboratory’s name came from. Most people who work in physics will have heard of the Cavendish, and may assume the laboratory, and the associated professorial chair, are named after Henry Cavendish, the man credited with discovering hydrogen, who also measured the density of the Earth, and carried out research into electricity. In fact, construction of the laboratory was funded by William Cavendish, 7th Duke of Devonshire. It was originally to be named the Devonshire Laboratory, but the first appointee as professor, James Clerk Maxwell, suggested it should be named the Cavendish instead, to honour not only its patron, but also the famous scientist, who happened to be the duke’s great uncle.1 Perhaps this was just as well. “The Devonshire” sounds as if it should instead be a hotel, or perhaps a brand of clotted cream. This raises the issue of the difference titles in the British peerage make to the names of buildings, positions and theorems named after distinguished people.

Oxford University’s equivalent of the Cavendish, the Clarendon Laboratory, was also named after a nobleman: Edward Hyde, 1st Earl of Clarendon, who, like Devonshire, also served as Chancellor of his university. In this instance, the laboratory was named after his title, as opposed to his surname. Had he not been an earl, Oxford could well have the Hyde Laboratory instead, which perhaps is where a Dr Jekyll would work.

Names of buildings is one thing, but do titles have an impact on names in physics itself? Returning to Cambridge, before Maxwell accepted the first Cavendish Chair, it was offered to and turned down by none other than Lord Kelvin. He was actually born William Thomson, but chose to take his title from a river that flows through Glasgow. He was eventually honoured by having the unit of temperature named after him. Had he not been made a peer, we might now be measuring temperatures in thomsons rather than kelvins! That could have caused confusion when it came to symbols, as T is now used for the unit of magnetic flux density, the tesla. T is also used in equations for the physical quantity of temperature. Fortunately, we don’t have to face such confusion as the Glaswegian river came to the rescue.

Lords Rayleigh (left) and Kelvin, c.1900 (public domain image)

Lords Rayleigh (left) and Kelvin, c.1900

Maxwell’s successor at the Cavendish was Lord Rayleigh. His name was originally John William Strutt, but he inherited the title from his father to become the 3rd Baron Rayleigh. He lends his name to Rayleigh scattering, which in simple terms is the answer to the most classic of all physics questions: why is the sky blue? “Strutt scattering” somehow wouldn’t sound quite as poetic. There is also a rather obscure unit of measurement in acoustics, the rayl, named after him. His son, the 4th Baron, followed up his father’s work on the sky’s light scattering, and as a result, another fairly obscure unit, the rayleigh, a measure of photon flux, is named after him.

There is further confusion for physics students when using American text books. The Americans don’t understand British titles, and therefore there are plenty of references to those famous physicists, John Strutt and William Thomson. The latter must surely have been the one who came up with Thomson’s model of the atom, the so-called “plum pudding”? No, in fact that was J. J. Thomson, Rayleigh’s successor as Cavendish professor. Thomson was never raised to the peerage, only receiving a mere kinghthood. But what if he had been? Perhaps he would have chosen the title Baron Cheetham, after his birthplace. That would have given us the Cheetham model of the atom, which perhaps sounds as if it was deliberately contrived to mislead people (cheat ’em!) Yet Thomson was disadvantaged by the fact the nucleus had not yet been discovered; it was hardly deliberate deception.

The discovery of the nucleus came about thanks to the work of Thomson’s successor at the Cavendish, Ernest Rutherford. He did receive a peerage, choosing the title Baron Rutherford of Nelson. Rutherford was unable to choose a purely geographical title based on his birthplace, Nelson in New Zealand, as a certain naval officer had beaten him to it. Otherwise, we may now have Nelson scattering, the Nelson Appleton Laboratory in Oxfordshire, and an element in the periodic table called nelsonium.

What happened to the titles that helped shape physics terminology? After all, before 1958, all titles were hereditary. Lords Kelvin and Rutherford both died without any sons to inherit their titles, which then became extinct. Lord Rayleigh’s title lives on, with the present 6th Baron still living in the family’s manor house, Terling Place in Essex. As for the universities’ wealthy patrons, there is still a Duke of Devonshire and Earl of Cavendish. Today, peerages are still occasionally granted to renowned scientists, but they usually choose titles based on their surnames. Combined with the fact that physics is more collaborative these days, and therefore new discoveries are less frequently named after individuals, it’s unlikely we’ll see aristocratic titles making their mark on physics in the same way in the future. It can be fun to invent fantasy titles, though. Anyone like to suggest an alternate, aristocratic name for the Higgs boson?

1 Reference: “A new era for the old Cavendish?” Physics World, October 2015, p. 12 (not available online)

One constant good: Semper eadem

The Queen in March 2015. Licensed under the Open Government Licence v3.0As a child, I remember reading in my treasured 1990 edition of the Guinness Book of Records about the longest serving monarchs. Back then, the book was a scholarly work, and amongst the detail, it gave the date, a quarter of a century in the future, when the Queen would take that record.

Today, that day has finally come. Much has been said of how the Queen has been a beacon of stability as the world changed around her. This has long been recognised. At the time of Her Majesty’s silver jubilee in 1977, Philip Larkin wrote:

In times when nothing stood
But worsened, or grew strange,
There was one constant good:
She did not change.

This idea of constancy in a rapidly changing world reminds me of the motto semper eadem: “always the same”. This was actually the motto of the first Queen Elizabeth, and has since been adopted by the city of Leicester. By all accounts of both Queens’ lives, it would seem far better suited to our present Queen Elizabeth than to her earlier namesake.

Return of the giant hogweed?

Giant Hogweed. Photo by Fritz Geller-Grimm, CC BY-SA 3.0This summer has seen numerous stories in the media about giant hogweed, including plenty of cases where people, particularly children, and even pets, have been injured after coming into contact with it. My fascination with the giant hogweed began in childhood when on holiday in Cornwall one year. There was an article in a local newspaper with a remarkably familiar story of some boys who had used stems of the plant to have a sword fight, and had been burned in the process. The idea of a plant that was not only big and impressive, but also dangerous, and even more dangerous in sunny weather, somehow appealed to me and seemed to be something worth looking out for.

It must have been the late ’80s when I saw that newspaper article. But then Genesis even released a song in the early ’70s entitled The return of the giant hogweed, which more or less tells the true-to-life story of how the plant was first brought here from the Caucasus Mountains (albeit with a touch of John Wyndham). Yet from the recent newspaper reports, you would think giant hogweed was a new threat that has only just emerged in this country.

Giant hogweed, Heracleum mantegazzianum, was first recorded as growing in the wild in Great Britain in Cambridgeshire in the 1820s, so it’s been here for 200 years and is hardly a new arrival. But why spoil a good headline? Some tabloids have even branded the plant the “Taliban weed“, claiming it comes from Afghanistan. (I thought the Caucasus were between Russia and Georgia.) The newspapers appear to have caused some panic among the public this summer, with some people scared to walk in the countryside as a result. Yet despite being on the lookout for this plant for the last 25 years, and walking in many parts of the country, I have very rarely seen it. It surely can’t be as widespread as the tabloids are making out. I suspect many people are confusing it with the native hogweed, Heracleum sphondylium. There was an article in the Oxford Times earlier this month where a lady was complaining about council inaction over “giant hogweed”, yet the plant shown in the picture is clearly not giant hogweed at all (it’s most probably common hogweed).

There are, however, some voices of common sense. Experts in Warwickshire have urged people not to let fear or giant hogweed spoil their enjoyment of the outdoors. Parents teach their children not to brush against stinging nettles, or for that matter not to eat deadly nightshade berries or mess with all sorts of other hazardous plants. People just need to know not to touch this particular plant, either. In that respect, the newspapers are performing a useful function. However, in a year or two, no doubt people will have forgotten about giant hogweed – exactly because it isn’t really that common – and in a few years the cycle will repeat with a load of new stories about people being injured by it. It’s not really the return of the giant hogweed, just the return of stories about it.

Giant hogweed towers over a well-protected expert. Photo by The New York State Department of Environmental Conservation, CC BY-NC-ND 2.0

Giant hogweed towers over a well-protected expert

It should be easy to identify giant hogweed, not least because of its size, with a height of up to 5 metres, leaves a metre long, flower umbels 50cm across, and stems up to 10cm in diameter. Its leaves are much more serrated than common hogweed, and the umbels contain far more individual flowers, whereas common hogweed typically only has a dozen per umbel. Giant hogweed also has purple blotches on its stem. It is a member of the Apiaceae or carrot family, and in common with relatives such as carrot and parsley, it is monocarpic, i.e. once it flowers, it dies. It usually grows as a biennial, putting out leaves in its first year, storing energy in its roots, then flowering in the second year. It can flower in a single year, or may take several years, particularly if it is cut back. However, it only flowers for one year, and doesn’t mature like a tree over the years, as some sources seem to imply. Its danger lies in chemicals called furocoumarins, which are a defence mechanism against various types of pest. These chemicals cause skin that has been in contact with the plant to burn when exposed to ultraviolet light, which is why the effects can be worse on a sunny day.

It is actually perfectly legal to grow giant hogweed in your garden, should you be so inclined. It was originally introduced as an ornamental plant, after all. These are a few laws that apply, the best known being the Wildlife and Countryside Act, which makes it illegal to plant or cause it to grow in the wild. This act usually only applies to animals, but a small number of invasive plants are specifically scheduled. Giant hogweed is also covered by hazardous waste regulations, so if it’s cut down, it can’t go in with the normal garden waste. Finally, recent laws give local authorities powers to order people who fail to control invasive plants on their land to act, ultimately with a hefty fine or even prison sentence if they ignore it. (The usual advice for controlling the plant is to use Roundup, but this is being progressively banned around the world due to health concerns – good news for giant hogweed.) I don’t really know why anyone would want to grow it in their garden. While it is a large and impressive plant, it does look like many of the common weeds that grow everywhere.

Giant hogweed can be an problem when it does colonise large areas, usually along river banks. It is a real issue along some rivers in Scotland in particular, as these dramatic images from a drone show. Not only does it prevent people from enjoying the river, it crowds out native plants, and once it does, the hole where the roots were causes the river bank to erode. This is an issue largely confined to waterways, though. The plant thrives next to water, which also carries the seeds downstream.

Paolo Mantegazza: cocaine and cohabitation

The oversize giant hogweed has an equally formidable-looking botanical name, Heracleum mantegazzianum. It is clear that the hogweed genus, Heracleum, comes from Heracles or Hercules, due to the plant’s Herculean size and stature. In the 19th century, when European explorers were discovering new plant species, they each classified plants they encountered as they saw fit. When giant hogweed was first brought to Great Britain, it was most likely known as Heracleum giganteum. French-Italian botanist and anthropologist Stefano Sommier (1848–1922), and Swiss-Italian doctor and botanist Emilio Levier (1839–1911) visited the Caucasus in the late 19th century, and named giant hogweed in honour of the Italian polymath Paolo Mantegazza. Their choice of name was to become the accepted scientific name for the plant, as is still used today.

Paolo Mantegazza

Paolo Mantegazza

Paolo Mantegazza (1831–1910) is himself a fascinating figure; a neurologist, physiologist, and anthropologist. He travelled and lived for a while in South America, and some of his best known work is on the effects of coca leaves, which he experienced first hand. Yet he was not only a scientist, but also an author of fiction. His The Year 3000 predicted technological developments including artificial intelligence, modern aircraft, prefabricated buildings, air conditioning, credit cards, and instant global communications. However, he didn’t just predict scientific and technological changes, but also social ones: for example, the couple depicted in his book spend a five year period together, “with love but not children”, before they marry. He also correctly predicted the First World War, with “One million deaths in a single day”. Just about the only thing he got wrong was the timescale, which was out by roughly a millennium.

It’s worth remembering that, at the time, the Catholic Church strongly influenced science and culture in Italy, and his views on sexual liberation can hardly have been met with official approval; nor could his scientific views, as an athiest and staunch defender of Darwinism. The Church may have found Mantegazza’s views toxic, whereas to others he was an impressive giant, which perhaps makes it fitting that the toxic but impressive giant hogweed is named after him.

Edited on 29 February 2016 to replace deleted Youtube video

TV licensing: i-Playing fair

BBC iPlayer

BBC iPlayer

As expected, the government have decided that the BBC should meet the cost of providing free TV Licences for over-75s. Also as expected, to soften the blow of an effective £600m a year cut in revenue, the BBC has been promised a change in legislation to allow the TV Licence to cover the BBC iPlayer. Leaving aside the rights or wrongs of making the neutral BBC pay for a government policy that exists for political reasons, I would like to focus on the practicalities of licensing the iPlayer.

It seems fair enough to close the loophole, which exists only because catch-up TV services such as iPlayer did not exist when the law was drafted. Extending the law to cover catch-up TV isn’t straightforward, however. It’s important to remember that a TV Licence is required to watch any broadcast TV, not just BBC channels. Even if a viewer has subscription-based pay TV and never watches the BBC, a licence is required in order to stay within the law. Extending the same principle to catch-up TV throws up the question of which sites would be covered. If it only applied to the BBC’s iPlayer, that would be a departure from the principle of universality: that the BBC is free to everyone at the point of consumption, and that there is no specific subscription charge for watching the BBC. But if the law is to encompass other catch-up sites, the line between catch-up TV and other online video is rather blurred. It seems clear that ITVPlayer should be covered, but what about the BT Sport app? How about videos on a newspaper’s website? What about video sharing websites such as Youtube, which sometimes show TV episodes on a pay-per-view basis? And what about shows from foreign TV stations that are available online?

Across the different news sources, there seem to be a range of suggestions as to what the new law could cover. Some suggest only the iPlayer; others that servies such as ITVPlayer would be included. There have been suggestions that iPlayer would be offered on a subscription basis, with TV Licence holders entering a code to watch for free, or that there would be a cheaper “digital only” TV Licence that would cover iPlayer use. At the moment, there are actually no details of the proposals, so all these are speculation. Let’s look at what the minister, John Whittingdale, actually said:

As part of these new arrangements, the Government will ensure that the BBC can adapt to a changing media landscape. The Government will therefore bring forward legislation in the next year to modernise the licence fee to cover public service broadcast catch-up TV.

The key phrase is “public service broadcast catch-up TV”. This doesn’t necessarily only apply to the BBC. I believe ITV, Channel 4 and Channel 5 all to varying degrees have public service requirements as conditions of their licences to broadcast: for example to broadcast news, children’s programmes and the arts. It seems likely that a change in the law would therefore also cover, ITVPlayer, 4oD and Demand5. It presumably wouldn’t cover Sky, BT Sport or Youtube as these can’t really be construed as public service broadcasters. That would be a slightly narrower coverage than the Licence as applied to broadcast TV. However, trying to make it broader could open a can of worms, as it could then apply to all manner of online video that few people would consider television at all.

The final question is whether the new licence requirements would be enforced by the BBC by requiring a licence number to be entered before watching programmes via the iPlayer website or apps. Technically, this should be fairly simple to implement. However, the BBC may not want to go down a road that could form the basis of a subscription model were the BBC’s Charter not to be renewed at some point in the future.

While the whole saga has been prompted by the funding arrangements for over-75s, it may be worth noting that one group of people who would be hit hardest by a licence for iPlayer would be university students. Students have always been required to buy a TV Licence for their individual rooms in university accommodation, but many now avoid this by using iPlayer to watch only catch-up TV. Given the huge increase in university tuition fees in recent years, students may resent having to pay more money out of their student loans in order to watch television, while wealthy over-75s all receive a non-means tested free licence. We therefore are back to where we started, with the question of whether making the BBC fund free TV Licences is really fair in the first place.

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