Channels, Services and Logical Channel Numbers (LCN)

With analogue television, a channel contains only one program stream. However, with digital television, multiple program steams, called services are contained within the channel. In each case, the channel identifier is fixed. For digital transmissions, ABC is usually transmitted on channels 12. Each service is assigned a Logical Channel Number (LCN). For ABC, there is ABC 1 (LCN 2, LCN 21), ABC 2 (LCN 22), ABC 3 (LCN 23) and ABC News 24 (LCN 24). Notice that the same programs can be transmitted on multiple services. For ABC, LCN 2 and LCN 21 have identical content.

If more than two channels for the same network are identified during a service scan, multiple two LCNs will be listed for each service. This usually happens when you are located near two geographically dispersed transmission points. For example, in Melbourn ABC is transmitted on ABV12, and in nearby Healsville on ABV35. If you are located near both transmission location, the service scan may pick up both ABV12 and ABV35, resulting in duplicate LCNs. (LCN 2 and LCN 21 are not duplicates.) One channel will be assigned LCNs 2, 21 to 24, and the second will be assigned some other LCN. The LCNs are included in the transmission stream, and if multiple recognised channels contain the same LCN, those in one channel should be assigned different LCNs; however, this does not always happen.

For the viewer, the what is important is the LCN. Since these are logical rather than physical channels, it means that GEM, which has LCN 90, has the same LCN in all regions in which it is transmitted.

Channels and channel identifiers

Channels and channel identifiers refer to the signal transmitted from a particular point.


A channel usually contains multiple services, each of which can be viewed. In Melbourne, the exceptions are MGV31 and MGV32, which only has one service (community TV).

Logical Channel Numbers (LCN)

An LCN is assigned to each service contained in the channel.

How to delete duplicate services

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