Im continously developing the ultimate rc-relay. If there exists such a thing. The hardware has christalled out nicely, but i still have to do some work on the software side. Right now it only works on one of the two channels. The most important thing to test for is the perriod between pulses. If this is too small its a bad signal.
My relays require 4 pulses to flip over the switch, both for the on-off and off-on transition. If it detects a spike it ignores the previous 3 and next 4 pulses. Failsafe detection is similar to marks system. if 4/60 pulses are bad it failsafes. It only comes out of failsafe after 60 good pulses. If the perriod between pulses becomes too long the system inmediatly goes into failsafe.
This seems to be a relyable system. Yet the most dangerous situation which can occur is when the receiver is switched off and the system is expected to failsafe. Its my experiance that if the failsafe and filtering algorithms arent good enough the relay may trigger in such a situation.
Keep your distance if you turn off your transmitter, you never know what will happen just before your system failsafes