I’ve had a few people ask me why they can’t receive MyTalk’s Digital TV station  despite being in a coverage area, and a few more people have landed on this blog by asking Google the same question, so I thought I should probably provide a public answer.
Some newer digital receivers seem to automatically pick up new stations belonging to an existing group of stations (for example, Southern Cross Ten in Canberra has in their group the main channel, a high definition channel, and the MyTalk channel), which means that you can tune in to the new stations without any hassle.
Older receivers, and many of the current cheaper receivers, do not perform this function, on them you need to scan for new channels manually. Exactly how you do this will depend on your receiver, so you should consult your instruction manual if you’re not sure, but in most cases there is a menu option available for this. If your receivers allows you to rescan the current channel, then tune to any other station in the group (for example, if MyTalk is 55 in your area, tune in to 5) and rescan the channel, this is a lot quicker than performing a full channel scan.