VIETNAMESE PRESCRIPTION REVIEW
BBC transmissions in Vietnamese are broadcast by High Frequency transmissions via the BBC Far Eastern Relay Station located a Kranji in Singapore.
In 1982, as part of the 1981-1991 audibility programme, the poor quality, unreliable HF programme feeds to Kranji from the UK were replaced with high quality feeds via the Indian Ocean Intelsat satellite. This led to a significant improvement in audibility of the Vietnamese transmissions. However, when the HF feeds were closed, particularly those within and adjacent to the international HF broadcast bands, listeners across Europe and Asia who had become accustomed to listening on these frequencies, found they could no longer listen to the Vietnamese transmissions.
A small improvement in audibility was achieved more recently when an extra 250kW transmitter, together with some new antennas, were installed at Kranji. The resulting increase in flexibility in scheduling the transmission facilities has led to a small increase in the strength of one or two frequencies.
It is becoming increasingly difficult to maintain audibility of the BBC transmissions due to the increase in congestion in the International HF Broadcasting bands. Many other broadcasters have improved their transmission facilities to this part of the world. In particular the private US Broadcasters have increased dramatically the number of transmitters they use to broadcast to Asia. Other Broadcasters have recently negotiated exchanges on transmission facilities in China and Japan. The resulting increase in congestion is likely to continue as other Broadcasters such as Voice of America, Radio Canada, Radio France and Radio Netherlands, are planning to build new, high power transmission facilities in the Far East/South East Asia. All of these developments compete for a finite number of frequencies.
The increase in both number and strength of signals will degrade the subjective audibility of BBC Transmissions.
To remain competitive the BBC will need additional high power HF transmission facilities in SE. Asia or the Far East. For example a new HF relay station in Thailand while not broadcasting in Vietnamese indirectly help improve the Vietnamese transmissions. The transfer of some transmissions to this new relay station would release transmission facilities at Singapore. The resulting increase in scheduling flexibility at Singapore may lead to a small increase in strength of the delivered signal.