said by RadioDoc :

So, what are you using these frequencies for during the 99.9% of the time when there is no need for an emergency network? There are no towers up.

The whole point of this network is to have it up and running all the time, to be taken over for critical communications when other networks are unavailable. It would take weeks to deploy, erect and activate a system such as you describe, far too late to do any good.