i've read all the negative about this unit. I have one and while I as well, experienced some troubles, with the exception of the first flight, the unit performs as advertised.
No reading on the first flight. Second on a C6-5 - 651', reasonable on this motor rocket combination. rest on C6-5's similar withing a few feet one way or the other.
However, my unit did experience a problem. The bottom row of segments on the LCD went out on the last launch. It's boxed up and on it's way back to Estes right now. We'll see how good thier turn around is.
You can test the unit very easily. Here is how it works. There is a switch on the side that does not start the timer, it appears that it still requires the mechnical Q switch to be triggered as well. it's a little wire cage that surrounds a spring on the Circuit board. It also appears that most people are having troubles because the unit lands mostly on it's side and not it's nose. I sent Estes a note to ask about that the ineffectiveness of the streamer. Hopefully, they will ask and engineer who will tell them to attache the streamer at the end or if in the middle to use 24" instead of 12. Would be worth some experimentation.
One note, I was the hit of the launch with the unit. Everyone wanted one, warts and all. They are very cool. Now if I could figure out how to deploy one from an HPR, that would be too cool!
Alan