To Africa's Highest Mountains

The VHF Telecommunications Route, East Africa, 1951-54

Prior to 1949, telephone and telecommunications, including long distance telephone and telegraph systems, relied on single or multiple pair telephone wires strung on telegraph poles. These tall poles were erected next to the railway tracks and alongside highways and streets, while the wires transmitted telephone, telegraph and radio signals.

There was a serious technical problem with overhead telephone line pairs: the characteristic frequency response limited the line to audio frequencies. The overhead pair of lines was capable of carrying only one or two audio (speech) channels at a time, dependent on the type of line. There was another problem in Africa. The overhead wires were vulnerable to breakage by elephants and giraffe, and to theft by local tribesmen who cut the copper wire to make bangles.

The demand for better communications and the pressing need for a multi-channel telephone system capable of catering for the needs of a variety of individual and business subscribers led Marconi engineers to develop a modern VHF radio communications repeater link system. The prototype, which used the VHF frequency band, was installed between Nairobi and Nakuru in Kenya, and was successfully tested in 1947-49.

In the early 1950s, the East African Posts & Telecommunications Administration replaced this 100-mile pro type system (J-route) with a VHF system. This system operated on "line of sight" and the terminals had to be in sight of each other. To maximize the distance between terminals, the survey crews had to select the highest possible sites available, and that meant climbing many of East Africa's highest mountains.

The route stretched a thousand miles, from mountaintop to mountaintop, from Kampala (Uganda), through Kenya, to Zanzibar and Dar es Salaam. It was truly a pioneering project, paralleling the development of the railroad from Mombasa (Kenya) to Lake Victoria and Uganda.

Gordon Mumford, who worked on this project, tell the story of this survey and construction in White Man's Drum and Drums of Rebellion. An Assistant Engineer, he was one of the men on the survey crews who ran radio strength tests between two locations, with one site transmitting and the other receiving. These safaris normally lasted four to eight weeks or longer. Sometimes Gordon worked with another crew member, but usually he was on his own for long periods of time, running tests around the clock in all kinds of weather. Their vehicles were left in the base camp, along with their African drivers and local labour employed to do chores around the camp, while the tests were run from the highest point possible..

Nasu Point

Nasu Point is on a headland jutting out into Lake Victoria, near Jinja. This was the first repeater in the chain from Kampala. This was one of the easiest locations because it was possible to drive right onto the site.

The Routes

Map showing the route from Kampala, through Kenya to Dar es Salaam via Zanzibar.

Photographs taken at some of the sites are shown on this page.

Sigulu Island

The island, five hours by launch from Jinja, was uninhabited because of the 1925 sleeping sickness epidemic. The men worked chest-deep in water to build this jetty to unload equipment. The site proved uneconomic to maintain. 

First, the project engineers decided what mountains would theoretically be suitable for repeater stations. When the survey teams first reached these mountains, there were no roads. They had to make a base camp, and set out on foot to climb the mountain. After making a track up the mountain, they had to manhandle all equipment, food, and water to the top site, using local people as porters.

Team members operated test transmitters and receivers 24-hours a day, testing radio signal strengths between two sites. They also returned to each site at various seasons of the year to test signal strengths for fading and other problems. Some sites that looked ideal could prove otherwise. Sites that seemed viable sometimes had to be abandoned after months of testing, and alternative sites had to be found and tested.

Map of Sigulu Island

Lugulu-Busia

The site on Sigulu Island in Lake Victoria was reached using launches,one hired from the Public Works Department and the other from Louis Leakey. The island was uninhabited because of a sleepy sickness epidemic in the 1920s, plus a large section of the mainland on the shores of the lake. It also proved to be uneconomic, because of its location, and was eventually abandoned. It was replaced by a site near Busia, close to the Uganda/Kenya border where there was a range of hills approximately 1000 feet above Lake Victoria. The road to the Lugulu-Busia site was very steep in places, and had to be blasted.

Gemba Peak

Gemba Peak (altitude 6000 feet) is approximately 3000 feet above Lake Victoria. View shows Rusinga Island from the test site. The site is approached from Kisii across the Lumbwe Valley to Kasigunga village, then by a road cut into the mountains. During heavy rains, the black cotton soil in the valley was often impassable. A launch was used between Kisumu and Kasigunga to cross the Kavarondo Gulf, bypassing the swamp in the Bue plains.

Loldiani Peak

Loldiani (altitude 10,000 feet) is about 7000 feet above the floor of the Rift Valley. Is it approached through Maji Mazuri and forest roads, with a departmental road cut through bamboo to the peak. Shortly after the emergency started, a farm on the edge of the forest was attacked. The gang was tracked to the base camp, and Gordon's labourers were arrested. After that incident, a permanent guard was placed on this site throughout the Emergency.

Individual Telephone Terminals

The terminals for the VHF routes were located in Kampala, Nakuru, Nairobi, Voi, Mombasa, Tanga, Zanzibar, and Dar es Salaam. Photo (left) shows the VHF survey safari vehicle at the bottom of the mast. The mast was on top of the main post office building. Photo (right) shows a rigger on top of the 150 foot mast. Gordon and Eric climbed the mast to connect the various antenna arrays.

To enable telephone subscribers and other systems to use the VHF radio repeater system for communications between cities and countries, there must be interfacing equipment between the systems. For example, long distance radio repeater links terminate in the carrier rooms of the public telephone exchange. There VHF signals are transformed into audio (speech) signals and passed through the telephone exchange to individual telephone subscribers. Similar systems existed in all terminals involved in the VHF repeater routes.

Mua Hills, near Machakos

There was also a repeater site at Kitindini on a peak in the Mua Hills with a clear view of Nairobi. Signals from this site were transmitted and received by terminal equipment in the main Nairobi carrier room. Photo shows foundations and base of the radio repeater station at Kitindini.

Kilimanjaro foothills (Njaro)

The project to build a road up to the shoulder between Mwenzi and Kibo peaks proved impractical because they encountered heavily forested terrain and steep ravines. It would have been expensive to build and maintain. Photo shows a 4 x 4 truck in an overgrown pit (abandoned elephant trap). It took nearly 5 hours to dig it out.

Chyulu Range

This area is now a part of the Tsavo National Park. It is a waterless area. During the survey, the vehicle bringing a 44-gallon drum of water and other supplies broke down. When it didn't turn up, Gordon, Geoff Perrins and Andrei (their driver) walked twenty miles to reach the Mombasa Road, and got a lift to Mac's Inn at Mtito Andei. This site was originally an alternative to the Kilimanjaro site, but it was abandoned, and moved to Mbwinzau.

Mbwinzau

Campsite was located on a large rock on top of Mbwinzau. Yagi aerial for test transmissions is pointed toward Kitindini, while the dipole aerial on the main tent was used for local (voice) communications with the other site during testing. This site is located alongside the main Mombasa road, and the tower is a prominent landmark, easily seen from the road. (see map below).

Mt. Vuria / Teita Hills

The summit was 2000 feet above the base camp, and was a five mile walk. We hired porters to carry the loads from the base camp to the top test site.

Zanzibar

This repeater station and tower is about 200 feet above sea level. It is on the northwest side of the island, about 30 miles north of the town of Zanzibar Island.

Map of Mbwinzau showing Camp

Once a site was approved, they constructed a rough track to prove that it was possible to get a Land Rover up to the site before a more permanent road was made. When there was a road to the site, buildings for equipment were constructed and radio masts installed. Finally, the technicians installed large directional antennae on the towers and connected the large duplicated diesel generators that provided power to the equipment. Finally, the repeater stations could be put into operation.

White Man's Drum and Drums of Rebellion by J. Gordon Mumford describe a slice of life in Kenya was in the early 1950s, and life on a working safari, including their many adventures during the survey and construction of this route.

Once they were camped on a high ridge on Gemba mountain in South Nyanza when there was a sudden storm during the night. The strong winds blew their tent down, and it collapsed on top of them and their test transmitters.

In another rain storm, this time in the Teita Mountains, a heavy truck that Gordon was driving was almost swept over a precipice on the road from Wundanyi and Vuria peak. The photo shows his survey vehicle on the left. Fortunately, the chassis stuck on the soft edge of the road. If it had gone over, it would have been a write-off.

Another incident in the Teita mountains occurred after the transmission towers were built. He was repairing the directional antenna on the top of the 120-foot tower working on the Vuria site, when freezing rain from the upper layers of air hit the tower.. Gordon was dressed only in a thin khaki shirt and shorts, and his hands and finger were soon numb with cold. He had to disconnect his safety belt and edge his way down the slippery steel tower, using the ten-inch bolts jutting from the tower legs as a ladder.

None of the African workers would stay overnight on the Mbwinzau range, because it was known to be a habitat for leopard. During the test period, his equipment stopped running in the night because it had run out of fuel. Taking his rifle, a flashlight, and an empty jerry can, he walked down to the lower camp to get fuel, and then made his way back to the upper camp. In the morning, his workers showed him the paw marks made by a leopard that had been following him.

These are just a few of the many adventures experienced by the safari crews.

For further information about his books about Kenya, see

White Man's Drum and Drums of Rebellion