Re detector circuit
: it's not very complicated, only 3 or 4 actual components.
The clues are good RF diode and a very sensitive meter! I just bought a couple of 300microamp full scale meters. Will do a little blog when I've tidied it up and boxed it.
Re Heli: can you post or mail me pics of the TX, RX and ESC please.
Brushed or Brushless motors?
Given manufacturer / model
numbers I might be able to figure out what the pissibolities are. No promises though 😉
Sounds to me like the TX stick is set up for forwards / backwards like a normal car or boat set up. I.e. for 0 to full speed in either direction is only half the stick travel.
0 is full down, giving you the full stick travel for the speed range. The ESC probably needs to be 're-educated' and the TX throttle stick re-programmed, IF at all possible with the TX you got with the Heli.
Re " P.S. Signals come from where Doug?" - Don't understand the question John ??
Cheers, Doug 😎