Following the failure of the north mast at Start Point in January, arrangements had to be made to provide back-up for 693 kHz while checks are carried out on the remaining mast, and of course to keep a service going during the works to rebuild the failed mast.
The choice of site was made somewhat easier by the presence of a former LF installation just east of West Prawle, four kms west of Start Point. A mast of approx 80 m, along with a ATH, were still present on the site.
A mobile MW transmitter has been deployed to the site by Arqiva.
We gather that this redundant mast was part of the Datatrak system. Datatrak was a medium-area LF automatic vehicle location (AVL) system that operated in the UK, Benelux countries, Germany and Austria. It was operated by Securicor Information Systems in the UK and by Siemens_Datatrak in mainland Europe. It was originally developed to fulfil a need for the monitoring of Securicor's own parcel and security vehicles, but was also marketed to a number of other customers. The system was a conventional hyperbolic positioning system where a number of stations making up a chain, transmit in sequence on a common pair of frequencies in the band 130 to 170 kHz. The receiver calculated its position and communicated this back to the control centre, (Swindon in the UK), by means of a UHF radio system that provided similar coverage to the LF network. There were apparently 14 Tx sites in the UK. |
