I'm re-posting this from the other thread about CW 4 for your consideration........
Before we make too much of this SOD thing and potential encryption, etc, let's remember something: the NYPD was the first agency to seek, and get, a waiver on narrowbanding SOLELY because of the cost of doing such a thing throughout the department was prohibitive. And the city has a lot less money now than it did then. And one of their other arguments were that the move to 700 was just down the road a bit.
But after the "interference" that was heard on the air during New Year's Eve at Times Square, I can see them investing a smaller amount of money now for a "mobilization" frequency or frequencies with a form of encryption and for field radio identification and control.
And considering what political priorities the present mayor of NYC has for the future which cost tons of money (and his personal and political disdain for the police), I could see the NYPD seeking yet another "waiver" for the 700 changeover, too, to avoid laying out the money for that.