I started flying last year with a Tactic TTX410 four channel transmitter and built a bunch of planes with Tactic's receivers. Now I want to step up a more sophisticated transmitter and looked to buy a Tactic TTX660 six-channel unit, only to find it is discontinued. In fact, the only transmitter available is the one I currently own. So, is this the death spiral for Tactic? Will I have to switch to a new system?