I'm currently using JR PCM receivers. Until recently, I was using PPM receivers, but I decided that I liked the idea of the failsafe that PCM provides.

The range check should come out the same with both PCM and PPM. If there is a problem, the PCM receiver is only masking the problem, not curing it. Eventually it could come back and bite ya.

I try to get a range check where the clear signal distance is the same, engine running and not. If there is a difference, I don't fly until I can find the reason. There are so many reasons to have problems it can take forever to list htem. The two that happem most often though are the wrong type of plug (non resistor instead of resistor) and loose connections/components.