"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 N264, March 16, 2014
BBC Indian Ocean Relay Stations: Five in a Row!
Some time ago, the BBC announced that they plan to close their Indian Ocean Relay Station at the end of the month, Saturday March 29. This station has been on the air for more than a quarter century and it will end its international shortwave service, though the local FM relay stations will still remain on air.
As a tribute to the lengthy service provided from this important radio station, we are planning to present two topics here in Wavescan. Next week, you will hear the story of the BBC Indian Ocean Relay Station; and this week, we present the story, Five in a Row, the steps leading up to the erection of their relay station in the Seychelles Islands.
Back at the end of last year, we presented the story of the temporary BBC relay station located at Francistown in Botswana, Africa. This station was hurriedly pieced together in an effort to counter the political events in neighboring Rhodesia, and it was officially identified as the BBC Central Africa Relay Station.
Four transmitters were installed, two mediumwave Continentals at 50 kW each from the United States, and two shortwave Marconi's at 10 kW each from England. This station was taken into service on December 30, 1965, and its last day of on air service was March 31, 1968.
Around the time when the station was closing, a question was raised in the British Parliament in London regarding this BBC Central Africa Relay Station. According to the Hansard Report, it was stated that the Francistown station was closing, and that additional antenna systems were under installation at the BBC Relay Station on Ascension Island. These new antennas would ensure, it was stated, adequate shortwave coverage into Rhodesia. This of course, would form only a temporary interim service into Rhodesia.
In June 1966, the BBC was investigating the possibility of utilizing a large ship as a BBC relay station for radio coverage into East Africa. The ship that they were looking at was a redundant aircraft carrier, HMS "Leviathan".
The good ship "Leviathan" was laid down at Tynside in England on October 18, 1943 as a nuclear powered aircraft carrier for use in the latter part of World War 2. This ship, uncompleted, was launched on June 7, 1945, just as World War 2 was coming to an end, and it simply lay around awaiting its destiny. But, it was never fully completed.
At the time when the BBC was investigating the possibility of taking the ship over as a relay broadcasting station, the suggestion was to have it stationed in the Mozambique Channel and that it would give radio coverage into Rhodesia and South Africa on behalf of the BBC. At the time, Rhodesia had made a unilateral declaration of independence, UDI, and the South African government was a strong supporter of the Smith administration in the former British colony.
It does seem at least mildly hypocritical that all this was going on at the same time that the BBC was complaining back home about the existence of unlicensed off shore stations on board ships and forts around the British Isles.
It is probable that this mobile shipboard radio station would transmit on mediumwave towards East Africa, though shortwave could later be considered. However, this radio project never materialized, and the entire concept was scrapped in May 1966. Two years later, the empty and uncompleted aircraft carrier "Leviathan" itself was sold, and scrapped.
However, around the same time, the BBC was also investigating the possibility of establishing a large relay station on the island of Aldabra for broadcast into East Africa. Aldabra is a tiny uninhabited atoll 500 miles off the coast of Africa, 300 miles north of Madagascar, and 500 miles from Zanzibar. The only personnel on the island are a few officials, caretakers and research officers.
The Aldabra atoll is 21 miles long, 8 miles wide and it is the second largest raised coral reef in the world. This atoll is made up of four small islets around a shallow lagoon, though no fresh water is available. There are many unique forms of life in the area, including an estimated 100,000 Giant Tortoises.
Back in 1966, the Royal Air Force was giving consideration to establishing an air base on Aldabra, and the American air force was interested in a joint collaboration with the RAF as a refueling station for American planes en route to Vietnam. American investment in the project would amount to
In 1966, the BBC chartered a 600 ton coastal vessel from Mombassa, the "Southern Skies" for a six week exploratory expedition to Aldabra. The BBC survey party was in contact with London via a shortwave SSB transmitter on the ship, and the BBC communicated with the ship via one of the high powered shortwave transmitters at Daventry. However, due to the incursion of tropical storm Angela, the survey expedition to Aldabra was cut short, and this project too was abandoned.
If the Aldabra project had materialized, it was envisioned that four high powered mediumwave transmitters at 750 kW each would be installed with four independent directional antenna systems beamed westwards towards Africa. These transmitters would be operated separately, or in pairs, or all with combined power on one mediumwave channel. Though not stated, if this station had been installed, it is probable that shortwave coverage would be added subsequently.
However, the British/American air force base never became a reality, so neither did the BBC relay station.
The next project in this sequence was the BBC relay station in the Seychelles Islands, and that of course, is our opening topic in Wavescan next week. So, what then were the Five in a Row? Here is the list:
Focus on Asia: On the Air Shortwave from India's First Capital City - The Calcutta Story
Quite recently, Jose Jacob VU2JOS in Hyderabad India sent us an email message in which he alerted us regarding the possible closure of VUC, the current shortwave station in Kolkata. He stated that the shortwave transmitter at Kolkata was scheduled to close down on February 22 as per orders from the headquarters of All India Radio in Delhi. However, the technical employees union in Kolkata protested this decision, and so the shortwave station still remains on the air, though for how much longer is uncertain.
Two matters arise out of this information:
1. If you do not yet have QSLs verifying the Indian regional shortwave stations, you should send reception reports to them while they are still on the air; it is known that all of these analog shortwave transmitters in India will one day be closed in favor of digital transmitters.
2. As Jose Jacob suggested, now would be an appropriate time to present a complete Station Profile on AIR Calcutta. So, here we go!
The city of Calcutta is located on the east bank of the Hooghly River, a branch of the Ganges River in the delta area, some 60 miles inland from the Bay of Bengal. Back in the era before the arrival of the British, there were just three small villages in the area:
The British East India Company was established in the area in 1690 and they bought the areas embracing the three villages, and thus the name Kolikata became the name for what became the entire city. In its Anglicized version, Kolikata became the very familiar Calcutta. Several different origins have been suggested for the original meaning of the name Calcutta and it would appear that the most logical would be that Kolikata, in the early Bengali language, meant the field of the goddess Kali.
In the days of strife between the colonial British and the local Bengali people, Calcutta became notorious for what is called the Black Hole of Calcutta, a small prison in which many prisoners died overnight some 2-1/2 centuries ago. In 1773 Calcutta became the national capital of all India, a title that it held for more than 1-1/4 centuries; Delhi became the national capital in 1911.
India's first newspaper, the Bengal Gazette, was printed in Calcutta in 1780; the first Christian missionary, William Carey, arrived in Calcutta in 1793; Calcutta was the 2nd largest city in the British Empire in the year 1900 (with London as the largest); the national anthems for both India and Bangladesh were composed in Calcutta by the nobel laureate Rabindranath Tagore; the city name was changed from the English Calcutta to the Bengali Kolkata in 2001; the port of Kolkata stretches for 20 miles on both sides of the river; and these days 14.1 million people live in greater Kolkata, the 3rd largest city in India.
Among the many tourist attractions in Kolkata are the ornate Victoria Memorial that was designed in the style of the Taj Mahal; the city zoo in which successful cross breeding between tigers and lions has been achieved; and the huge Banyan Tree more than 250 years old and covering more than 4 acres.
Most of the early wireless experiments in India took place in the Calcutta area and it was back in the year 1849, more than 1-1/2 centuries ago, that the first wireless experiments were undertaken by Dr. Sir William O'Shaughnessy, Superintendent of Telegraphs. He successfully transmitted wireless signals across the Huldee River 3/4 mile wide with a wire along each bank of the river, and a metal plate at the end of each wire immersed in the water.
It seems that each succeeding Electrician in Calcutta conducted similar experiments and next came Mr. Blissett. In 1858, he conducted similar wireless experiments with the use of a long wire on each bank of a river and in this way achieved fair success.
Mr. Winter followed and he made some astute observations regarding cross modulation of Morse signals between parallel telegraph wires on the same poles in 1873. Three years later, Mr. Schwendler carried out similar cross-river communications across the River Hooghly at Barrackpore, near Calcutta, using parallel wires with metal plates submerged in the water.
Mr. W. P. Johnston was next and he repeated the same experiments across a nearby waterway 200 yards wide on September 9, 1879. Nine years later, he carried out many similar experiments across nearby canals in the Calcutta area, and also across the River Hooghly itself.
Mr. Melhuish was next and he discovered that the wires lying on the bank on each side of the river need to be at least as long as the river is wide in order to achieve reliable communication.
The first experimental work on the transmission and reception of radio signals in India was carried out by Dr. Sir Jagadish Chandra Bose. Towards the end of the year 1894, Bose began his experimentation with wireless, and in November 1895 he gave a public demonstration in the Calcutta Town Hall with Bengal's Lieutenant Governor Sir William Mackenzie in attendance.
In this public demonstration, Bose transmitted wireless signals at a wavelength of just 1/2 inch over a distance of 75 ft. through several solid walls. He also used a wireless signal to ring a bell at a distance, and to fire a gun remotely.
India's first wireless station was established just three years later (1902) and this was installed at Sandheads on Saugor Island out in the Bay of Bengal. The original callsign for this station was ROS, though when regular international callsigns were mandated worldwide, this call was amended to VWS.
During this same era, another wireless station was installed in the area, though this time much closer to Calcutta itself. This station was licensed under the callsign VWC and it was installed a little northeast of the city itself. When radio replaced wireless, a new location was chosen, just north of Calcutta.
Station VWC is still in use today, around a century after its original installation, and it was noted a few years ago with time signals for which QSL cards were issued.
That's as far as we go in the Calcutta story today, but in two weeks time, we plan to present the story of early experimental radio broadcasting.
What is a Kilohertz?
In every DX program on the air, in all radio DX magazines, and in the identification announcements from shortwave stations, the technical word kilohertz is used. So today, we ask the question: What is a kilohertz?
In the early days of experimental wireless development, it was common practice to calibrate electromagnetic waves by measuring the distance from one crest to the next crest in much the same way as you might measure the waves of the ocean, from one crest to the next. This distance is called the wavelength, and because many of the prominent early experimenters were European, it came to be measured electrically in metres.
Thus you will find the dials of most of the very old radio receivers marked in metres. In the medium wave broadcast band, one station in particular might be on the air for example on a wavelength of 200 metres, and another on 300 metres. On shortwave, one station could be shown as 30.99 metres, and another on 30.96 metres.
But, there's another way of calibrating a radio signal. Instead of measuring the distance between crests, or length of complete wave cycles, you can count how many of those complete cycles pass a fixed point in one second. This is known as the frequency.
The existence of electromagnetic waves was first demonstrated by German physicist Heinrich Hertz, and in 1930 the International Electrotechnical Commission, or IEC, established the unit of frequency of one cycle per second as being one Hertz, in his honor. This is abbreviated with a capital H and a small z.
Following standard metric usage, a frequency of 1,000 cycles per second, or 1,000 Hz, is thus equal to 1 kilohertz.
As time went by, it was discovered that measuring a radio signal by its frequency in kilohertz was more accurate and easier to express than its wavelength in metres. In addition, as the broadcast bands became more crowded, it was decided by international convention to adopt on mediumwave a 10 kilohertz separation between channels in the western hemisphere, and a 9 kilohertz separation in the rest of the world, including longwave in Europe. On shortwave, where signals have a narrower bandwidth, a 5 kHz separation between channels was adopted globally.
In spite of this, however, radio stations in Europe continued to announce their spot on the MW or LW dial in metres, right up until June 1984. During that month, they switched to using kilohertz instead, like most other regions had already done.
There is an inverse relationship between metres and kilohertz of 1:300,000. You can divide the wavelength in metres, or the frequency in kilohertz, into 300,000, and obtain the reciprocal.
As an example, for a shortwave station such as WWV which broadcasts on 10,000 kilohertz, you can divide 10,000 into 300,000 and see that its wavelength is 30 metres (just above the 31 metre broadcast band). Decades ago when I lived in the London area, the BBC had a 150 kW mediumwave transmitter there on 330 metres carrying Radio 4. Today that same transmitter now carries Radio 5 Live. You can divide 330 into 300,000 and see that the frequency being used is 909 kilohertz.
Sometimes, instead of kilohertz, you might find a radio station channel designated in megahertz. Longwave and mediumwave stations always use kilohertz, and VHF (FM) stations always use megahertz. When you hear that a station is on 89.9 FM, the frequency being used is actually 89.9 megahertz. But on the shortwave bands, between the mediumwave and FM bands, both kilohertz and megahertz are used.
To convert back and forth between kilohertz and megahertz, all you need to do is move the decimal point by three places, remembering that 1,000 kilohertz equals 1 megahertz. Thus for example, the shortwave channel 30.99 metres can be expressed as either 9680 kilohertz, or 9.68 megahertz.
The standard abbreviations for these three radio terms are expressed in this way:
|Kilohertz||kHz||Small k, capital H, and small z|
|Megahertz||MHz||Capital M, capital H, and small z|