Why bagpipes sound as they do

I wrote this somewhat technical article because Bagpipe players nowadays use an electronic instrument to tune their pipes, so that all the instruments in a band sound similar to each other on each note of the scale. The instrument requires the operator to take a reading from each note and then apply an “offset” correction to decide if it is properly in tune. This is a bit mathematical and tends to confuse people who are not technically or mathematically inclined. This article tries to make clear what it is all about.

Preliminary Note: Musicians speak of the ‘pitch’ of a musical note, and engineers prefer to talk of ‘frequency’. ‘Pitch’ and ‘Timbre’ are words that describe what our ears perceive when various musical notes are played singly or at the same time as one another. They are words that describe the subjective experience people have when  they listen to music. Frequency on the other hand is what we measure using scientific instruments. If a string on a violin or guitar etc. vibrates at a certain rate, say 440 vibrations per second, a classical musician will say they are hearing “A440” or “concert pitch”. It is the note called ‘A’ above the middle A note on the piano. In the middle of last century we techies used to say that the frequency of that vibration was 440 cycles per second. But in non-english speaking countries, other units were given to this vibrational speed (frequency). The Germans were always world leaders in this type of engineering, and they gave the name of a famous German scientist (Hertz) to the unit of frequency. Other countries had other names and there was a battle to arrive at standardised terminology. Somewhere around 1970, the Germans won the fight, and the whole world agreed to use the name ‘Hertz” (Hz) to describe the unit of vibrational rate, or frequency. For the record then, the number of vibrations per second (frequency) of a vibrating body or air-pressure wave is defined as the number of Hertz. 1 Hertz (Hz) is exactly equal to one cycle per second. There is no difference. It is just terminology.

Ever since early Egyptian times, or maybe earlier still, it was understood that if a number of musical notes were played, either together as a chord or rapidly after one another, they sounded better if the various notes had frequencies that were simple fractional numbers of each other. The simplest possible case is when the frequency of a particular note is exactly double that of another (a 2:1 ratio). Musicians will say they are one octave apart and they harmonise perfectly.  The result is very pleasing to the ear. A frequency ratio between the two notes of 3:1 is called a perfect fifth by musicians and is also very pleasing to the ear. It’s not surprising because some of the peaks of the two sound waves impinge on the listening ear at the same instant, and at moments when they do coincide, their powers are added together. Notes in harmony boost each other.

Most modern instruments have diatonic scales. That means there are 12 steps in the octave from the lowest to the highest pitched note (Including tones and semi-tones). If we look at how the scale is put together we see that the ratio between the frequencies of each pair of adjacent notes is the same as between any other adjacent pair. This is actually not exactly the ratio that pleases the human ear most, but it is close enough to still be pleasing.  Because all the intervals are the same, different instruments playing in different keys can play together and it will sound good. A scale with these intervals between notes is called an even-tempered scale and it is a good compromise which allows compatibility of different instruments playing in different keys. The average human ear accepts the slight inaccuracies in the case of most instruments

But the bagpipes are a different thing. The notes of the bagpipe chanter do not follow and even-tempered scale. The various notes are altered from the standard diatonic scale so that they will harmonize better with the drones. (For those who don’t know, the drones are the long pipes that rest on the pipers shoulder and create a deep ‘droning’ sound like a vacuum cleaner). Many pipers think the drones are fairly unimportant in the total sound produced by the pipes, but actually, I am coming to the realization that the entire scale system of the bagpipes is surely based on the characteristics of the bass drone reed. So, we should start with that reed and work up to the chanter. (The chanter is the tube with note-holes in it that the piper holds out in front of him and plays fingerings on to achieve a tune).

The sound we hear from a reed depends on three main things. (Reeds are what make the sound in the bagpipes. They consist in essence of thin wafers of reed or synthetic material that vibrate when air flows over and through them).

  • The material the reed is made from
  • The dimensions of the reed
  • the acoustical enclosure that the reed is played in (i.e. the drone pipe itself in this case)

There is a fourth factor with reeds such as clarinet reeds where the musicians lips are directly on the reed and he/she can influence the sound the reed makes by blowing it differently. This is not relevant in the bagpipes because the reeds are enclosed within pre-tuned cavities.

Let’s get back to the bass drone reed on the bagpipes. this reed within its drone pipe and driven by a constant stream of air from the bag, vibrates at a fundamental frequency of around 115 Hz (vibrations per second). But apart from that fundamental frequency, the reed and enclosure all produce many harmonics which are multiples of the fundamental frequency, and actually, other overtones which are not exact multiples of the fundamental frequency are also produced. But ignore the stray overtones and stick to the exact harmonics for now.

The tenor drone has a fundamental (basic frequency) of exactly twice the base drone fundamental and therefore vibrates at approximately 230 Hz. It too produces harmonics and overtones and because the fundamentals of the base and tenor drones are exact multiples of each other, the harmonics and overtones will be very similar. These harmonics and overtones will therefore harmonize and produce many pleasing pressure peaks in the sound wave.

Moving up then to the chanter, the Tonic note of the scale is called low-A and that is tuned to be an exact multiple of the base and tenor drones, one octave up from the tenor drones. In other words, the low-A on the chanter is tuned to about 460 Hz. This is arbitrary and not laid down as a strict rule, and the modern trend is to increase the frequency of all the pipes to make them sound sharper and more lively.

In normal classical instruments played in orchestras, that A note is traditionally tuned to 440 Hz and that is known as concert pitch. It is however true that the trend, even in conventional instruments, is to make concert pitch a little sharper than 440 Hz.

But now, here is where the pipes are dissimilar to all the other orchestral instruments. The notes produced by the bagpipe chanter are selected to harmonise with all the rich harmonics produced by the drones and the scale notes are therefore not the same as the normal diotonic scale of classical instruments. The scale is not an even-tempered scale as explained earlier. It is instead called a just-tempered scale which is actually a more accurate division of the octave, and the notes on the chanter scale harmonize more beautifully with the harmonics of the drones to produce the full sound that bagpipe enthusiasts love so much.  But here’s the rub.

Most of the electronic tuning devices we can buy, except for the very expensive ones, are all set to tune an instrument to an even-tempered scale. Because the notes of the chanter vary from those of an even-tempered scale, we need to understand that the readings of each note on a standard tuning device will be in error by the amount that the chanter note differs from the even-tempered scale. This means that we have to apply a mathematical correction to the readings we get on the electronic tester in order to tune the chanter correctly to match the drone’s harmonics. This correction is known as an offset and is given in a unit called ‘cents’ in the table issued with the instrument. The unit ‘cent’ or 1/100 th of an octave was invented more than 2 000 years ago by Pythagoras, and is simply a way of way of specifying a note far more acurately that just talking about tones and semi-tones. So for instance, the offset to be applied to the F note on the chanter is -16 cents. The F note on the chanter is close to an F# on other instruments and by applying this offset of -16 cents we will end up tuning the F to a bagpipe F and not a piano F.

Just a complication on all the above. Even with choosing chanter notes that better match the drone characteristics, it is not possible to find chanter notes that harmonize with all the available drone harmonics. This means that bagpipe manufacturers have to choose which harmonics to match their chanters to and it leaves the field open to choice. There is not total agreement between the experts which exact notes the chanter should play because it is possible to select different drone harmonics to match to, and that changes the chanter scale quite a lot. That’s why not all pipes sound the same. Some experts believe for instance that High G should be at 819 Hz and others would pitch it at 842.4 Hz. Quite a difference. Piobaireachd players apparently prefer an even lower pitch of around 770 Hz. (Piobaireach is a Gaelic word for the original classsical type of bagpipe music).

Sailing the Peloponnese peninsula (Part 1)

Athens was modernised and spruced up for the 2004 Olympic games and is really quite smart these days, and perhaps surprisingly, spotlessly clean. There is a bright and speedy train which transports its passengers, partially above and partially below ground, from ‘Venizelosto’ airport to various stations in the city. The escalator at ‘Plaka’ station lofts the passengers to street level and disgorges them onto the street at the foot of the acropolis hill. It was a bit of a bit of a culture shock for me, emerging into the daylight at Plaka station and raising my eyes to the massive street map next to  the exit, to find that all the names and instructions were only in Greek script. I knew the name of my B&B establishment and which street it was in but it wasn’t going to help if I couldn’t read the map. I stared blankly at the direction finder for a few moments but was then quite relieved to realize that I knew the cymbals from study days, and that when one replaced the cymbals with the Latin alphabet equivalents, the place-names started to make sense.There was Alpha (α) = a, Beta (β) = b, Omega (π) = z, Theta (φ)=t  along with the rest of the familiar gang, and the place names suddenly became understandable.

I met up with my friends and would-be yacht crewmates and we spent a few days exploring the tourist attractions of the ‘Monastariaki’ & ‘Plaka’ districts and selecting our eating places from a plethora of similar offerings. Here are a few pictures of what those areas looked like.

We also enjoyed the Acropolis and Acropolis museum and also various other ancient attractions.

Our crew of 6 friends arrived separately over the next few days and when we had all done sightseeing, it was time to board the yacht. So off we went to the marina at Kalamaki south of the big harbour of Piraeus. This was by far the biggest marina I had ever seen and is surely one of the largest in the world. There are about 2 000 walk-on mooring there and they are arranged as many fingers reaching out into the yacht harbor. The boats are all reversed into their parking places and tied up securely alongside each other until it is time for them to sail.

The boat was a Bavaria 40. She was a comfortable sloop and rigged strictly for charter. This meant that she had only two sails. They were a working type jib with self-furling gear and a battenless main which furled into the mast. She had an electric anchor windlass and a full automated navigation station with chart plotter etc. She was fitted with a massive Bimini and spray dodger which protected us from the sun but made it difficult to see the sails. The accommodation was good but we had fewer bunks than we had anticipated. We were supposed to be 7 people on the boat and there should have been sufficient bunking in the three cabins and the saloon. The problem was that the saloon only had one narrow berth in it and not the two we had expected. This could still have worked if there had been three couples but there were only two couples and three singles. We considered changing to a bigger boat but the cost was a lot more and we couldn’t stretch to that. One woman then decided to quit the boat. She was the last person to have been invited and she was anyway the veteran of a number of charters of this type, so she decided she would be happier doing her own thing. We were all sad to see her leave but she went off to the islands on her own and apparently had a great time. The face in this picture is that of DSC02946 Constantine, the operator of the charter company. A great salesman and vibrant personality who was actually a dentist by training but preferred messing about in boats. I think he did pretty well out of it.

Although the charter was for one week, we effectively got only 6 sailing days because of hand-over procedures and times. We spent the first night on board in the marina at Athens. The agent took us through the boat and then we stowed all our gear, had a couple of night-caps up in the copious cockpit and settled down  for the night, filled with excitement for the morrow.

In my next blog post I’ll describe the sailing routes we took and our week on the Mediterranean sea.


What is Piobaireachd

The known history of the Scottish bagpipes goes back about 600 years. Yes that’s all folks. So that means that all those movies like ‘Brave heart’ which date back to centuries before the pipes came to Scotland, incorrectly show scenes including bagpipes.

In any case, in the early days of bagpipe music, most of it was sort of the equivalent of classical music in the European cultures. It was called ‘Ceol Mor’ which meant Major music. The less formal or perhaps one might say, Pop music, which has gained in popularity ever since and is now commonplace is called ‘Ceol Beag’ which means minor music. (Not that Ceol Beag should be scoffed at. Some of it is complex and excellent). Although these were the original Gaelic names for the two music genres, Ceol Mor became better known as Piobaireachd (often simplified incorrectly to Pibroch). I say incorrectly because of the word roots. Piob-air means quite simply, pipe tune. Not sure exactly what the eachd suffix means but it recurs in another interesting word which I will now explain. Apart from being played on the Great Highland Bagpipes, this music can be sounded by the human voice. In that case, instead of calling it Piobaireachd, the first part of the word changes from Piob to Cannt which clearly means voice tune. (Chant, cant, cantata etc. Also the part of the pipes that sings is called the chanter.) In other words if we replace the Piob in Piobaireachd with Cannt, we get Canntaireachd. This is indeed what the sung version of Piobaireachd is called and it can be performed as a sort of acapella performance or sung as an accompaniment to the pipes. Now the sounds made in singing canntaireachd are not random but very specific. Each sound indicates the fingering that is used when playing the piece on the pipes. So when canntaireachd is sung it has the tune of the music and also tells the piper how it must be played. It is music in its own right but is also used as a way a piper can remember a tune to play it from memory on the pipes. When pipe music was first played, the modern musical stave and notation had not yet been invented. So it was mainly passed on verbally although a few people actually wrote down the Canntaireachd words as a form of musical notation.

Here is a link to a short Piobaireachd, played on the pipes, but simultaneously sung as canntaireachd. The scenery in this clip is also superb and the words of the chant are superimposed on the scenery so you can see how they are written.


Piobaireachd tunes are written onto musical staves using special symbols to describe special timings etc. but it is not possible to fully capture Piobaireachd in this manner. So modern stave notation is only a guide and allows a lot of room for self-interpretation. No two pipers will play a Piobaireachd exactly the same way and the same piper may also play it differently on different occasions. The same air can be played sadly or happily etc. depending on circumstances. The chief or whatever might summons his piper and ask for melancholy music or whatever. You may remember the words of ‘Green Hills’ (Scottish soldier) which say “He called his piper, his trusty piper, and bad him sound the lay of Piobaireachd hard to play”. Those were the request of a dying man and the Piobaireachd would have been played as it says, as a lay.

The first part of the tune is called ‘The ground’ and the tune is usually quite simple and always played slowly. But although simple, even the ground uses rhythms that are not heard in any other music, bagpipes or any other. There is for example a thing called an echo-beat where a quick grace note is inserted between two melody notes but then followed by an extended echo of the same grace note.  The ground consists of three or four lines of music after which it is played over and again but each time with different added embellishments. (A bit like the Baroque that developed later in other parts of Europe). Each embellishment (also called rudiments) becomes more complex and the piper is encouraged to express himself uniquely. After the last embellishment is played, the simple ground is played once more and the audience know that the piece is coming to an end. Not all possible embellishments are played in each rendering and a Piobaireachd can run for anything between 10 and 30 minutes. This is quite challenging for the piper and of course, if he is not good, for the audience as well.


Broadcasting – All in Good Time

I was involved in the technical side of broadcasting in South Africa from 1965 till 1996. It was a fascinating 31 years and I was privileged to see amazing developments in broadcasting equipment. But SABC was not just a user of broadcasting equipment. It was a very successful manufacturer.

The early SABC modeled itself on the BBC which was widely acknowledged as a world leader in excellence, both in production and in the research, development and manufacturing of broadcast equipment. In the 1960s we were importing a lot of equipment from America, Switzerland and the U.K. but we had some brilliant engineering brains in South Africa and they started the SABC manufacturing workshops in Judith’s Paarl in Johannesburg. There we would manufacture from absolute scratch, everything from turntables to tape recorders to mixing desks and even microphones. We even improved on some of the technical equipment we had bought in and some of the SABC innovations were taken up and used by the international community. I will tell more about the things we manufactured in a later article but today I would like to talk about the the master clock systems used over the years by the SABC.

Time keeping has always been important in broadcasting. Listeners want to switch on the radio station of their choice at a given time and hear the program or news bulletin they were promised for that time slot. People also want to set their watches to a universal time signal so that everyone’s watches correspond. It’s important for meetings etc. In the early days of broadcasting, anything within 1 second of the correct astronomical time was good enough.

Image result for image of gents of leicester pendulum master clock
Pre-1973 master clock at SABC

the effective length that decides its period is the distance from the knife edge to the centre of gravity. ie, roughly to the centre point of the bob. The old Gents master clock had a compound metal pendulum shaft and a bob of a different metal. The bob could slide freely up and down the shaft and the bottom of the bob rested on and was carried by the bottom plate of the shaft. The theory was that on a hot day, the shaft would expand and get longer, thereby slowing the clock down but the bob would expand from the bottom upwards and compensate for the change in the shaft length. It worked pretty well but it was not perfect. As a result, the clock would drift slightly out of time as the weather changed. We at the SABC used to listen in every day on a short wave radio to the time -signals from the astronomical observatory. If our clock was more than 1 second slow, we would place a small weight of about 1 or 2 grams on the top of the bob. This was above the centre of gravity of the pendulum and therefore raised the centre of gravity minisculy. This was just enough to bring it back into time for the day. If Our clock was running a bit fast by the observatory, we would add the small weight to the bottom of the bob, lower the pendulum centre of gravity and slow the clock down a tad. The system worked but it was very tedious.So the engineers at the Judith’s paarl workshops designed and built a system that would electronically listen to the time pips from the observatory and then use a relay mechanism to mechanically place a fairly heavy metal marble onto, or remove it from a platform affixed half way up the pendulum shaft. This then adjusted the effective length of the pendulum and altered its speed. The system worked brilliantly and never needed manual intervention any more.

The SABC ran on these pendulum clocks until TV arrived on the scene in 1973. But TV stations require far more accurate time-keeping than one can ever get from a mechanical device. So the old clocks were replaced by a form of atomic clock called a Rubidium standard. This is a whole nother story and maybe I will get to that in another article. The Rubidium was incredibly accurate but even that became redundant years later when things like cell phone systems required an even greater degree of exactness.


Colour mixing – Additive & Subtractive

I was asked on Quora to answer why when we mix primary light colours together they add up to white and when we mix primary dye colours together they yield black. Well here’s the thing.

Our eyes are receptors. i.e. they are like radio receiving antennae that are tuned to pick up particular wavelengths in the electromagnetic spectrum, and we call those wavelengths light. The wavelengths of these radiations are roughly in the range 400 -700 nm (billionths of a metre). We have receptors in our eyes called ‘rods’ that simply sense brightness. If we had no other receptors we would see the world like a black, grey and white photograph. But fortunately we also have receptors that pick up others wavelengths and they are called cones. The three types of cones ere each sensitive to a range of wavelengths but each peak at a particular wavelength. I nicked this image from Wikipedia showing the response curves of each type of colour receptor. The x-axis is graduated in nm. (Billionths of a metre).

if we projected wavelengths of 445 nm, 535 nm & 575 nm onto a screen, the images formed would trigger all three sets of cones and we would perceive three coloured dots or shapes something like this.

But in addition to being able to sense the three primary colours, our brains interpret a mixture of primary colour stimulations as a new colour. So here’s what we would see if we project overlapping discs of the above wavelengths of light.

But when we look at an object, say a picture or anything else around us, we are not looking at something that transmits wavelengths of light from within itself. Object around us are seen by us because light from somewhere, e.g. the sun or a lamp etc., falls onto the object and bounces off that object (is reflected) into our eyes. But some of the wavelengths in the incident light, i.e the light falling on the object, are not reflected into our eyes because they are absorbed by the particular object. Which wavelengths will be absorbed and which reflected is complex and depends on the atomic structure of the object and the wavelength of the incident light.

So for instance, If a white light falls onto an object, we know from the images above that means that all visible wavelengths are falling onto the object. That object then absorbs some of the wavelengths and reflects others. If for instance, the object absorbed all the blue waves of the incident white light and reflected the red and green wavelengths, we would see the object as red/green which we know from the above appears to us as yellow. You can work out from the above what the absorption of other wavelengths would lead our eyes to perceive.

If the incident light was not full-bandwidth white light but was say just blue, the object it fell on would only be seen by us at all if it could reflect blue light. If it was a green object for instance and we shone blue light onto it, we would perceive it as colourless or black.

Of course we are talking total absorption or reflection here, but if an object absorbed for instance, 80% of the red part of the white light falling on it. 50% of the the blue and 20% of the green, it might be rendered thus to our eyes.

The possible combinations are infinite.

The early life of a late-start bag-piper

I was always a lazy bugger, and learning to play an instrument entails a lot of practice. So after learning a few chords on the guitar as a teenager, I decided and declared that I would never be a musician and gave it up as a bad job.

But when I retired 50 years later my world changed a bit. I am a South African by birth, but there was some Scottish blood in the ancestral line and we grew up in a household where a lot of Scottish music and poetry was heard. My dad played the bagpipes and so did my uncles, i.e. Dad’s brothers. We learned to love the Scottish culture and when I retired and finally had time to do these things, I joined the Caledonian society in Cape Town. They had a group of members who were being taught the chanter by the society’s honorary piper. I did not think I had a hope in hell of learning to play at 70 years old, but I joined the chanter group and have been attending lessons for 2 years now. One starts on the practice chanter, a small wind instrument that makes use of a plastic reed (two plastic blades vibrating against each other) to produce its characteristic but unusual sound. It has nine finger-holes on the pipe below the reed and when one blows air down the blowpipe end, it passes over and through the reed, sets it vibrating and produces musical notes. The distance from the reed to the open holes decided what pitch a note will have and it is possible to play musical scales up and down the chanter although the intervals between the notes are not the same as on modern instruments.

Practice chanter

The practice chanter with its plastic reed can be played inside an apartment without disturbing the neighbours. That is why it is called a practice chanter. One problem with the practice chanter as a performing instrument though is that the musician cannot blow endlessly into the blow-stick without pausing for a quick breath. But the music does not usually allow for breathing stoppages so the effect on the listener is not very salutary. Another problem with the practice chanter is that it plays only single notes at any one time. Some notes are played very fast in quick sequences and this helps to make it more interesting but one cannot play chords on it. Both of these shortcomings are addressed to some degree by the addition to the chanter of a bag full of air and 3 other pipes that produce droning sounds at two different pitches. These harmonize with the chanter in different ways on different notes and make it sound much more colourful. So the whole ensemble resembles a sort of 5 armed octopus of quintopus if you prefer.

Neal playing the bagpipes
First lesson on the full set of pipes

Here is a picture of yours truly with his brand new set of bagpipes trying to learn the not-easy technique of keeping the bag full of air, squeezing it under the arm with a constant pressure and actually trying to play a tune all at the same time. The actual full set of pipes does not use a plastic chanter reed as with the practice chanter. It uses a reed made, would you believe it, of a special type of reed (or cane). It makes an extremely loud sound which cannot be produced in an apartment without raising a lynch-mob, and in addition, the three drones all have reeds in them as well. The sound produced has a primal quality to it that would scare off most enemies, but it is balm to the Celtic soul.

How am I doing with my learning? Well it is conventional wisdom that it takes a young man with a good ear and attitude 7 years to learn the basics and he then enters a second seven year period in which he strives to become a master. I quote from the ‘Highland Bagpipe Tutor Student Manual’. “Actually, there is an old quotation that starts ‘To the make of a piper go seven years… At the end of his seven years one born to it will stand at the start of knowledge, and leaning a fond ear to the drone, he may have parley with old folks of old affairs.’ (Neil Munro from The Lost Pibroch 1896) This quote reflect not only a much earlier practice of several years of apprenticeship and indenture to learn the art, but also a contemporary reality.” 

I started at 70 and had never previously shown any musical talent so let’s just say I am about where I probably should be. I have learned to read pipe sheet-music however and with a bit of practice each day, my teacher is happy with my progress. The main thing is that I really enjoy it and it adds meaning to the tapering down phase of a busy life.

One of my favourite pipe tunes goes by the name of “Black Bear”, so I have mischievously created the calling card below

Black bear calling card web

How Namibia got FM Radio

In 1969, years before the start of Television in South Africa, we were entertained by radio programs. In South Africa itself, we could listen on Short-wave and in all the bigger centres we had Medium-Wave. Both of these are what we call AM (Amplitude-Modulated) systems. Later on we got FM and the quality was amazing.

You cannot broadcast sound, i.e. audio, directly. Sounds produce pressure waves that attack our ears at a rate of between 50 and 15 000 pulses/second. The electrical signals that correspond to these sound waves are accordingly of  extremely low frequency when compared to radio waves and they could not be radiated from an antenna. To radiate from an antenna, we need to use signals that vibrate at a couple of hundred thousand cycles/second up to many millions of cycles/second. So what we do is, we generate these higher frequencies and push them into antennas that will radiate them into the space around and above the antenna. Medium-wave and short wave transmissions work by radiating the energy away into near-space where it is refracted (bent) by magnetic layers in the atmosphere and caused to bend back towards the earth. It then touches down again at a distance of many km from the transmitting antenna. The exact skip-distance (technical term) from origin to reception point depends on the frequency of the transmitted wave, the angle of the antenna to the surface of the earth,  and also to some degree on magnetic conditions in the atmosphere. These conditions change all the time as radiation from the sun ionizes various layers of atmosphere. In this way it is possible to shoot a signal into the sky in say Johannesburg and receive it in Cape Town or London.

Higher frequencies than those used for medium and short-wave radio can also be transmitted. As the frequency rises however, the way that the wave is propagated through the atmosphere changes gradually. When we get above the short-wave band, say roughly to wavelengths shorter than 10 metres i.e frequencies higher than 30 MHz (30 million vibrations per second), waves sent off into space will no longer be refracted back to Earth. At those frequencies the energy in the wave will simply carry it straight on out into space where it will travel forever or until it bumps into something and gets absorbed. But these so called VHF (Very High Frequency), UHF (Ultra High Frequency), and Microwaves can be used for what we line-of-sight or terrestrial transmissions between places on earth that can see each other. The transmission antenna is designed to send the waves in a beam (exactly like a torch beam) to the receive point. (A torch beam is a beam of radio energy and is only different in that it is in the frequency band that human eyes can see. Eyes are actually radio receiving antennae tuned to the extremely high frequency, GHz (Gigahertz) range. Visible waves are between 400 and 700 nm (nano-metres) in length.)

So we wanted to send some music through the air but we could not and instead we sent a steady beam of radio waves that had no direct meaning for us humans. Well, here’s the secret of transmitting the music or other intelligence we want to receive. The basic beam  of high frequency radio energy that we can transmit is called the “carrier-wave”. But we modulate the carrier wave with the sound waves we want to transmit. Modulation means that we change the shape of the carrier in some way so that when it reaches the receiver, we can detect these changes, discard the carrier and retrieve the original intelligence. Modulation can be done in any way that will change the shape of the carrier in a recognisable manner. In AM radio (Amplitude Modulated Radio), we cause the carrier to get weaker or stronger  directly in proportion to the strength of the modulating signal. i.e. the radio Graph of an Amplitude Modulated carrier
program. In this diagram that I lifted from the internet, you will see that the outer shape of the top part of the modulated carrier (the upper sideband) has the same form as the original modulating soundwave. Actually the bottom shape of the modulated carrier also carries the same information upside-down and that is known as the lower sideband. In practice we delete the carrier and the lower sideband in the average AM receiver and are left with just one copy of the original modulating sound wave.

So much for AM but what and why do we consider FM to be a better system? Well in FM (Frequency Modulation), we have a carrier as before and we change its shape with the modulating signal as before. It’s only that we use a different method of modulation. Instead of varying the amplitude of the carrier, we vary the frequency of the carrier from moment to moment in proportion to the amplitude of the modulating signal. So a loud sound makes the carrier vibrate faster and a soft sound makes it vibrate slower. For complex reasons that I won’t try to describe here, this can only be done if the carrier frequency is very high. That is why the FM radio band tunes from 88 to 108 Mhz (Million cycles/second), many times higher in frequency that the medium-wave band and even more so than the short-wave band. The reason we use FM is that AM transmissions get interfered with by all sort of things. A car spark plug or a fluorescent light or a switched-mode electronic power supply or an electric drill  etc. all radiate signals into space and these are almost all AM type signals. When these interfering signals reach your receiver at the same time as the transmission you want to hear, your radio cannot discriminate and receives both. The result is that AM signals are greatly troubled by interfering noise sources. Frequency modulation

None of the devices mentioned above generate FM type radiation however so when we are looking for frequency variations in the receiver we can ignore all the amplitude varying interference and that means that FM radio is quiet and noise free. Here’s a graphic illustration of how FM modulation works.

So, back to Namibia and FM. In 1969, Namibia could only receive Shortwave radio from Johannesburg or overseas and shortwave does not generally produce good quality. It was decided to extend the growing FM transmitter network from South Africa to Namibia (Then called South-West Africa). Well that was all very well, but how could the radio programs be sent to Windhoek so that they could be put onto the FM transmitters? Within South Africa, there was a network of telephone lines that carried the radio station signals to each transmitter on each hill so that it could be broadcast. But at that stage, there were no telephone lines between South Africa and Namibia. To solve the problem, the SABC built a short-wave receiver station in Windhoek. A receiver hall was filled with highly sophisticated German-built receiving equipment fed off highly sophisticated aerials that could make a reasonable job of receiving the South African radio stations from the Johannesburg short-wave transmitters. The quality was very much better than any domestic short-wave receiver could manage, and whilst it was not high fidelity music quality, it was pretty good. FM transmitter stations were then built on the mountain outside Windhoek and at Oshakati on the Ovamboland border and the signals received at the Windhoek receiver station were fed by local post office lines to these transmitters. The SABC then also built radio studios in Windhoek to produce local radio programs in English, Afrikaans, Ovambo, Herero and the Damara-nama languages.

And so FM broadcasting came to Namibia and I’m pleased that I was there and could be part of getting it all going.

Bamboo incense burner

Just to complete the set of blog articles on things I have made of bamboo, this one on an incense burner.

I  sometimes burn incense to create an atmosphere and I needed a burner to stop the ash from falling all over the place. I had salvaged some lengths of bamboo that someone else had discarded & I felt they lent themselves to this little project. Some of the Joss Sticks I have are quite long and they are best burned in a holder at an angle to the vertical so that their ash falls into a suitable collection tray. So I cut a 500mm piece of the bamboo and split it in the length to form the collection tray. The burner needed to stand on a stable base and I considered ways of creating that. I could have attached small feet under my half-tube of bamboo or I could have just sanded down the underside of the bamboo to create a flat base to rest on. Flattening the bottom was an appealing approach but it would have taken too much wood off the underside and left it flimsy. Eventually I decided to use a shorter section of the same bamboo and glue and rivet that onto the actual burner. With a lick of varnish it looked sort of arty and the short under-piece could be sanded to provide the necessary flat support surface. So here are views of my incense burner from above and from the side. It goes well with my chanter quiver and music stand that I have described in previous articles.

Musical bamboo

In an earlier blog article I described the bamboo quiver I made to carry my Bagpipe practice chanter around. Well, after that I still had some bamboo left over, so I decided to  make myself a music stand on a similar theme. Actually I didn’t quite make the whole thing.

I happened to have an old paraffin torch lying around. One of these decorative devices Bamboo torchone plants in the ground to create atmosphere when having people round for a braai. (South African word for barbecue). it is basically a piece of bamboo about a metre and a half in length. The upper end is split into a number of thin fingers which are then bound around a metal paraffin torch to create a pleasant flickering orange light. I tossed the burner away and also the binding ties that kept the upper fingers cupped around the burner. I then turned the thing upside-down so that the fingers became legs on which the bamboo could stand on a hard surface. Music stand from front.To give it some stability, I put a wooden spacer in between the fingers and pulled that up to splay the fingers into a reasonably Music frame tiltedwide base. I then made a wooden collar that could slide up and down the pole and I put a threaded thumbscrew into that so I could lock it at various heights on the pole so that a musician can sit or stand whilst using the stand. I then cut slivers of bamboo and screwed them together to make the actual sheet music support. This support frame swivels on the wooden collar that slides on the upright, allowing the user to tilt the music support frame to a convenient angle. The music frame only has one screw per joint and the thing is carefully measured, so it can fold up quite small if required for transportation. In this picture of it folded, it has a terry clip for mounting it. But this was later replaced by the wooded collar and thumbscrewMusic support folded web.jpg
I mentioned higher up. The tall upright in the middle is supposed to look like a musical note (crotchet) but it has a practical purpose too. It is a counter balance to offset the weight of the frame below and make the whole assembly more stable. The head of the crotchet leans to the right because the frame is mounted off to the left of the upright pole and the crotchet shape of the counterbalance helps to distribute the weight properly. The support frame itself is also designed to resemble a # musical sharp note. At the base of the frame, I have fashioned a shelf to support the sheet music and it has three little bamboo fingers pivoted on its front edge to retain the music.

All in all it is probably more arty than practical but it does work if one is careful with it. I have also recently acquired a neat little book-light that clips onto the top of the upright pole and lights the sheet music very effectively in a darkened room.


Bamboos and boxes

Provide the base support for the chanter

So when I started to learn to play the bagpipes, the first thing I had to purchase was a practice chanter. The full set of bagpipes uses a hide or synthetic bag to provide a steady flow of air through the chanter and the drones. The drones are the three pipes that rest on the pipers shoulder and they just make different bass notes to support the chanter. IMG_0505The chanter itself though is the pipe with finger holes in it that makes the notes of the tune. Here is a photo of yours truly taken by my bagpipe teacher when I went for a lesson with my new Chanter reedpipes. There is a reed in the chanter that vibrates when a stream of air from the bag passes over and through it. But here’s the thing. A bagpipe chanter makes a heck of a loud sound (so,me would say noise), and so do the drones. If you practiced playing them in your apartment, some neighbour would sooner or later shoot you. So in modern times, the practice chanter was developed. It is similar to the actual chanter, but the reed is made of plastic and is relatively un-noisy. There is no bag so the air to sound the practice chanter is provided directly by the player blowing down a blow stick which is connected directly to the practice chanter.

So having set the scene, let’s get back to the title of this blog article, i.e. ‘Bamboos and boxes’.

Chanter quiver comp
Chanter quiver

Any musical instrument should be protected for transportation and since I had some bamboo lying around, I sawed off a length and used it to make a carrying case for my practice chanter. The cap and strap are made of leather. I thought it was quite arty looking and would be a convenient way of carrying the chanter around. Here is a picture of what I called ‘The Quiver’. It worked O.K. but it is quite a long and bulky object and I realised after a while that it was not very practical. So I made a container of a different design for the chanter. It is a little foam lined, hinged box with cutouts in the foam to cushion the chanter.

To transport the chanter in this box, one unplugs the blowstick from the lower part and stows them side by side. The reed has to be removed too because it would be too vulnerable if it was left protruding from the playing tube. The reed and also a couple of spare reeds get popped into a small plastic pill box with a desiccant to keep the reeds moisture free. Piper 2 nealPractice chanter reeds are made of plastic and don’t work well when wet. Real chanter reeds are made of special Indian reed and they have to be moist if they are to be coaxed into making any sounds at all.