If it is anything like Melbourne, GEM Canberra LCN will be taken over by the new MPEG4 HD service, and GEM will revert to standard definition. Looks like GEM Ccanberra will be on either LCN 85 or 86, and presumably the new SD service on the other one. In Melbourne it was a bit more obvious as we had a second Gem LCN for about 6 weeks before the changeover. The really confusing thing was that the new SD sevice appropriated the LCN of eXtra, and eXtra took the LCN of the discontinued eXtra2.
Now, I am sure this makes a lot of sense to everyone.
Ian