programmes into Rhodesia by building a radio relay station in Francistown, in the then Bechuanaland Protectorate, now Botswana. The Rhodesian Government retaliated by clandestinely building a 400 000 watt transmitter nicknamed "Big Bertha", in order to jam the signal from the smaller BBC transmitter. Programmes about Rhodesia were subjected to jamming, but other programmes were not affected. In 1968, the BBC ceased broadcasting from Francistown, and the relay station was transferred to the Government of Botswana. Speaking at the opening of the new RBC Centre in Pocket Hill in 1970, President Clifford Dupont said that few other countries had been subject "to such a barrage of hostile propaganda over the air", and that the new centre would contribute to the RBC's very successful role "in combatting this insidious offensive". The RBC operated two main services, the English-language General Service (or National Network), aimed at the white audience, and the African Service, broadcasting in English, Shona and Ndebele, aimed at black listeners. The RBC also established three community stations with a multi-racial audience, Radio Jacaranda (Salisbury), Radio Matopos (Bulawayo) and Radio Manica (Umtali). In 1975, an Ndebele language service operating out of Bulawayo, known as Radio Mthwakazi, was established, using the "Big Bertha" transmitter previously used to jam the BBC's broadcasts from Francistown. As armed opposition to white minority rule mounted in the 1970s, Africans in Rhodesia increasingly began to turn to short wave radio broadcasts from neighbouring countries, which carried programmes from exiled nationalist movements, with the Zimbabwe African National Union's Voice of Zimbabwe operating from Mozambique, and the rival Zimbabwe African People's Union's Voice of the Revolution operating from Zambia. In order to counter this, the RBC installed an FM network, while the government distributed FM-only receivers to chiefs and village headmen in the Tribal Trust Lands. It also ran campaigns promoting FM-only receivers, pointing out that they were exempt from the annual licence fee, and how short wave broadcasts were affected by static noise and required retuning between frequencies throughout the day. Transition to independence In 1979, following the adoption of a new constitution, Rhodesia was renamed Zimbabwe Rhodesia, and in common with other state institutions which were renamed, the state broadcaster was renamed the Zimbabwe Rhodesia Broadcasting Corporation (ZRBC) under an amendment to the Broadcasting Act. It also used the name "Voice of Zimbabwe Rhodesia" (VZR) on air. In addition, the change of name saw the debut