"Wavescan" is a weekly program for long distance radio hobbyists produced by Dr. Adrian M. Peterson, Coordinator of International Relations for Adventist World Radio. AWR carries the program over many of its stations (including shortwave). Adrian Peterson is a highly regarded DXer and radio historian, and often includes features on radio history in his program. We are reproducing those features below, with Dr. Peterson's permission and assistance.
Wavescan N265, March 23, 2014
BBC Indian Ocean Relay Station Seychelles: The End of an Era
On Saturday, March 29, the shortwave service from the BBC Indian Ocean Relay Station in the Seychelles Islands came to an end after 26 years of broadcasting into East Africa. This shortwave service is ended, though the lone remaining FM station operated by the BBC in the Seychelles Islands will remain on the air.
The Seychelles Islands are listed as an African country, located nearly a thousand miles east from the continent itself. A total of 155 islands are listed officially as belonging to the Seychelles, though only 40 are permanently inhabited. The total area of all of these islands is just 175 square miles, though they are scattered around an area of 400,000 square miles in the Indian Ocean.
Some of the islands are described geologically as granitic, while others are semi-tropical coral islands and atolls. The largest island is Mahe, with Victoria as the capital city. Two other major islands are Praslin and La Digue.
The total population in all of the Seychelles Islands is a little less than 100,000, all of whom can trace their ancestry back to France, England, Africa, China or India. The national languages are English and French, though most people also speak the local Creole which is French derived. Tourism is one of their main sources of income.
There are many life forms in the Seychelles that are quite unique, such as the Black Parrot, which is their national bird. Other unique life forms are the strange Jellyfish Tree which thus far has evaded every form of propagation, and the coconut tree coco de mer with its huge double coconut, which can weigh up to 50 lbs each.
It is thought that the first visitors to the Seychelles Islands were Austronesians from Indonesia who passed through the area more than a thousand years ago. The next visitors came in from the Maldive Islands around 800 years ago.
The first European visitor was the famous Portuguese explorer Vasco da Gama who was en route to India in 1502. The first known European landing in the islands was made by Captain Sharpeigh of the East India Company in January 1609; and a French expedition from Mauritius visited Mahe Island in 1742.
Fourteen years later, the French laid claim to the Seychelles Islands by placing an inscribed Stone of Possession at La Poudriere (Victoria) on November 1, 1756. Then a few years later again, the first permanent inhabitants in these islands arrived from Mauritius. Though the Seychelles were originally a French possession, they were granted to England by the Treaty of Paris in 1814; and they assumed independence on June 29, 1976.
It was back in the year 1978 that the BBC gave recognition to the fact that it would be advisable to establish a relay station somewhere in the area, though because of a slowdown in the economy in England, funding was not available. However, three years later, the BBC dropped its programming in the Italian and Maltese languages in order to provide funding for this projected new station.
The BBC then began negotiations with the Seychelles government; and on August 8, 1983, they announced in their DX program, Waveguide, that the projected new shortwave station would be ready for service five years later. The BBC and the Seychelles government signed an agreement in 1985, and work on the new station began during the following year.
The new BBC Indian Ocean Relay Station was constructed at Anse Mahe on the west coast of the island of Mahe and a swampy mangrove area was filled in for this purpose. The plans for the new station originally called for four shortwave transmitters, 2 at 300 kW and 2 Marconis at 250 kW, together with a total of six four-band curtain antennas suspended from four self-standing towers. The total cost for this project was estimated at £8 million. However, when the project was completed, only two shortwave transmitters were installed, both Marconi Model B6131 at 250 kW.
An official ceremony took place on June 9, 1986 to mark the beginning of construction; two years later initial test transmissions were radiated; and the station was taken into regular service on September 25, 1988. An opening ceremony was staged a few days later on October 7. Programming beamed into East Africa was progressively transferred from the BBC Cyprus to this new station in the Seychelles.
In order to ascertain the effective coverage area for the new BBC Indian Ocean Relay Station, the BBC offered full data QSL cards, though only for listeners in the target areas in Africa. However, generally speaking, the staff at the Seychelles station did issue QSL cards for all reception reports sent direct to the station itself.
Programming for the BBC Seychelles came direct from London and it was made up usually of the BBC World Service in English, the BBC African Service, and programming in the Somali language. This scheduling was on the air via the two transmitters in parallel for around a dozen hours daily.
The first BBC FM station in the Seychelles was inaugurated in Victoria on 106.2 MHz in 1995; and this was followed in mid 2004 with the installation of two additional FM stations, at Anse Soleil on 105.2 and Pointe aux Sel on 105.6.
The BBC celebrated the 20th anniversary of their Indian Ocean Relay Station on October 2, 2008. At the time, they stated that 9 million people were listening to the relay programming from this shortwave station.
Then five years later, they announced that the station would be closed. The chosen date was Saturday March 29. The shortwave station is now silent; though we understand that one of their downlink FM stations, Victoria, will remain on the air with programming from the BBC African Service.
The World's Most Inaccurate Scientific Measurement
As we are aware, the accepted measurement for a radio channel is expressed in metres or kilohertz. Back a century or more ago, the usual measurement of the channel was given in the metric style, metres. This term expressed the distance between two successive crests of the propagated radio signal, like the two successive waves in the sea.
Initially, the actual wavelength of the earliest wireless transmitters was determined by the natural wavelength of the transmitting equipment together with the antenna system. However, when the usage of tuned radio transmitters was introduced, a shift in terminology took place and the identification of radio channels began to change from wavelength in metres to frequency in kilocycles.
Back in those times, it was understood that the relationship between wavelength in metres and frequency in kilocycles was 1:300,000. That is, if you divide wavelength or kilocycles into 300,000, then you will obtain the reciprocal.
For example, the well known chonohertz station, WWV, transmits exactly on 10,000 kilohertz. Divide that figure into 300,000 and you obtain the wavelength at exactly 30 metres. However, we ask the question: How accurate is the accepted relationship between metres and kilocycles, or kilohertz as we say today?
The exact length of a metre was accepted in the year 1791 as 1/10 millionth part of the distance from the equator to the North Pole at sea level. In later years, this distance has been refined for greater accuracy, though the concept remains the same.
This same distance, a metre, is also expressed as how far light will travel in a vacuum in 1/299,792,458th of a second. As a comparison, light could travel seven times around the Earth in one second; and it takes light approximately 8 minutes to travel from the Sun to the Earth. Now, electricity and light travel at the same speed.
The number 299,792,458 is certainly almost 300,000,000, but not exactly. In fact there is a difference of 207,452, an error of approximately .07%. Thus, if WWV is transmitting on exactly 10,000 kHz, then the exact wavelength would be approximately 29.98 metres, not exactly 30 metres, a difference of 2 centimetres, about 3/4 inch.
So, does this popular conversion rate between metres and kilohertz at 1:300,000 qualify as the world's most inaccurate scientific measurement? Yeah, probably! Does it really matter? No, probably not!