I can't speak for the city officially, of course, but the existing system has/had a life expectancy that puts it up for renewal/replacement around 2010. Plus, if you are going to have a provincial ambulance service, for example, or people working in multiple places (i.e. what you would be doing if Area X which is on the 700 system calls for Area B's help), you'll want everyone to be able to talk to one another - which is the meaning behind the buzzword "interoperability". If Calgary keeps operating its 800 system, that means that anyone using the 700 system will only be able to talk to them through bridges and patches, and any Calgary units heading out of the city will probably not be able to talk to other units at all (because they will be out of range of their 800 system). Besides, with the 23% tax hike Bronco and his ilk just announced, I think the taxpayers of Calgary would be keen to accept a concept where Calgary's $ expended on maintaining their tower sites and Smartzone controllers is redirected back to be able to be spent elsewhere - because if Calgary goes on the 700 system, all they will have to pay for is radios. The province is going to pick up 100% of the tab on towers, networking, zone controllers/computer links/system infrastructure, and all that. The only thing any agency on the system will have to pay for is the radios they use on the net.