Brian O'Meara is flying that airframe as well I think.
The device you found is the one I was talking about. There is no math to determine the value of the frame count it gives. So you are getting data, but there is no reliable means to know what the data mean.
Since 2.4 is digital it is sort of there or not. Fluctuations may, or may not. be meaningful. As long as the radio receives sufficient signal it keeps working. I suppose you could set a super conservative alarm, but not sure that will help.
Out of curiosity, what RX are you using??