The need for DAB-FM Shared Aperture Antennas grew with DAB coming to the market. FM Radio Broadcasting Services in Europe transmit from a small number of high power stations. This provides the most cost-effective way of providing a nationwide service. Five stations transmit from each antenna in the UK. Each station is either 10 or 20kW per channel. The broadcast services include FM and DAB transmissions plus new services
Furthermore, the current surge in mobile radio, as well as broadcasting, shows the true economic value of “vertical real estate”. It has highlighted the difficulty in finding available space on existing structures. Environmental considerations mean that local Zoning or Planning Authorities are reluctant to permit the building of ever more structures.
DAB-FM Shared Aperture Antennas
Some years ago the BBC approached AlanDick with a request to design an antenna. It had to fit the space occupied by the existing FM antennas. We embarked on a development project to achieve this without any serious effect on the FM antenna. The antenna also had to be easy to install, with minimum downtime for the FM services. However, it needed to have minimum impact on the FM antenna radiation pattern. Furthermore, the minimum effect on the return loss of the FM was essential. All this while meeting the specification for a DAB antenna! The FM antennas supplied by AlanDick to the BBC include two types depending on the mounting structure.
Square Arrays (FM Crossbow)
The FM Crossbow antenna fits on square structures. This also provides an omnidirectional Horizontal Radiation Pattern from an array of 4 panels mounted around a square structure.
Finally, for more information please download the following datasheet which provides more detailed information. Also, please contact the AlanDick sales team by calling us. Alternatively, out of hours please use our contact us page and we will be pleased to get in touch as soon as possible.