Check out this site - http://www.anra.org.au/ This is the website of the Australian Narrowcast Radio Association.
Overlooking Gordonvale Mill from Relay Site
"Narrowcasting is a category of Australian broadcasting which was created with the passage in 1992 of the Broadcasting Services Act.
The term “narrowcasting” describes a radio or television service whose reception is limited in some way, such as being targeted to special interest groups, being intended for limited locations (for example, arenas or business premises), being provided during a limited period to cover a special event, to provide programs of limited appeal, or for some other reason." (from www.anra.org.au site)
antenna on a narrowcast site
Many of our local Christian Radio services in the area I live are Narrowcast services. These services are able to provide affordable radio to lower density populated areas. Considering that the whole Atherton Tablelands area has a population of approx 46,000 people, operating huge Community based services in each town is not viable. However, smaller narrowcast services can provide a positive alternative for our local area.