- About transmitters
- Forms of transmitter list
- Basic information
- Advanced information
- Standby transmitters
- Day/Night switching of AM services
The transmitter information presented in this search facility is derived from the ACMA's records of licensed broadcasting transmitters. The inclusion of a transmitter in the search results indicates the existence of a transmitter licence for the service, however it does not guarantee that the particular transmitter is operating. While every effort has been made to ensure the accuracy of the transmitter information presented, the ACMA cannot guarantee the information to be free from errors.
When comparing transmitter locations with other spatial data such as satellite imagery or GIS topographic data, discrepancies will inevitably be encountered. These discrepancies are usually the result of accuracy limitations in the acquisition and/or presentation of the spatial data.
The positional accuracy of spatial data, including satellite imagery such as that available via Google Earth and Google Maps, may be subject to considerable variation due to limitations in acquisition, processing and display of the data.
The transmitter list for a broadcaster presented by this search facility is available in several forms.
This is the web page returned when a broadcaster's callsign link is selected from the initial postcode or place name search query. Only the most basic information about each transmitter is included.
The advanced forms of the transmitter list are not displayed as web pages but are presented as links to data in alternative formats appropriate for use in different applications or for graphical display:
- CSV file - comma separated value text file, which can be opened by many different software applications including spreadsheets and databases;
- Google Earth Placemark - this is in a spatial data format known as KML format and is normally associated with the Google Earth application, although many other software applications can also display this data;
- Viewing the transmitter list in Google Maps - this is the Google Earth Placemark data displayed in the user's web browser via the Google Maps web service.
These links are included on the web page returned when a broadcaster's callsign link is selected from the initial postcode or place name search query.
The following information about transmitters is included in all forms of the transmitter list for a broadcaster:
A descriptive name for the geographic area in which the transmitter's signal is intended to be received.
For television services, whether the transmission is analog or digital; for radio services, whether the transmission is AM or FM.
In the basic transmitter list, the mode is conveyed by colour coding of the background of the list item, with a colour key at the top of the list.
In the CSV file, the mode is identified textually, being one of "Analog TV", "Digital TV", "AM Radio" or "FM Radio".
In the Google Earth Placemark form of the transmitter list, and when the transmitter list is viewed in Google Maps, transmitter icons are colour coded as follows:
|both Analog TV and Digital TV|
The identifier used to refer to the part of the radio-frequency spectrum used for transmitting a television service.
The frequency of a radio service, expressed in megahertz (MHz) for FM radio services and kilohertz (kHz) for AM radio services.
The polarisation of the transmitted signal depends on the configuration of the transmit antenna's radiating elements. The recognised types of polarisation are:
- horizontal - power is transmitted via horizontal elements;
- vertical - power is transmitted via vertical elements;
- mixed - power is transmitted via both horizontal and vertical elements, in equal proportions; and
- dual - power is transmitted in some directions via horizontal elements, and in other directions via vertical elements.
Television services normally transmit with either horizontal or vertical polarisation, though several dual polarisation services exist for implementation reasons. FM radio services normally transmit with either mixed or vertical polarisation, although horizontal polarisation is occasionally used for implementation reasons. AM radio services always transmit with vertical polarisation.
Antennas used for domestic reception nearly always receive in only one plane of polarisation, and the antenna elements should be oriented to match the transmitted polarisation.
For radio services, polarisation is not displayed in the basic transmitter list as in most circumstances reception of these services does not require consideration of the antenna's orientation. It is included in the advanced forms of the transmitter list as a matter of technical correctness.
A description of the transmitter's location.
The following additional information about transmitters is included in the advanced forms of the transmitter list:
The value, in Hertz, of:
- the vision carrier frequency of an Analog TV transmission;
- the centre frequency of a Digital TV transmission;
- the carrier frequency of AM and FM Radio transmissions.
Frequency offsets from the nominal carrier or centre frequency are used for some services to improve reception in the presence of other services with certain frequency relationships to the wanted service. Any applicable frequency offset will be included in this value.
For AM radio services, the transmitter power is listed. For FM radio and television services, the Effective Radiated Power (ERP) is listed.
The type of radiation pattern used by the transmitter:
- OD - omnidirectional;
- DA - directional.
The maximum height above ground level, from the base of the mast or tower, of:
- the top of the radiating structure of an omnidirectional AM radio service;
- the top of the highest radiating element of a directional AM radio service;
- the electrical centre of the antenna of an FM radio or television service.
The geographic coordinates (longitude, latitude) of the transmitter's location are in decimal degrees, referred to the GDA94 datum. Coordinates in Google Earth Placemark files are referred to the WGS84 datum, however as the discrepancy between GDA94 coordinates and WGS84 coordinates is currently less than 1 metre, the GDA94 coordinates are used directly.
Some broadcasters maintain standby transmitters at alternate transmitter sites, which are included in some other ACMA publications. Standby transmitters are not normally included in these transmitter lists.
Some AM radio services operate with different antenna radiation patterns and transmitter powers depending on whether it is day-time or night-time, to improve reception during the day and minimise interference during the night. Only the day-time operating parameters are shown in these transmitter lists.