Thread: FM or PCM??
View Single Post
Old 02-12-2004, 02:47 PM
Senior Member
Join Date: Sep 2002
Location: Lewisville, TX
Posts: 669
Likes: 0
Received 0 Likes on 0 Posts
Default RE: FM or PCM??

As an addition to what AirBearMA said:

"If you get a number of bad consecutive data frames in a row, the PCM receiver will drive the servos to failsafe position (ASSUMING FAILSAFE POSITIONS ARE PROGRAMMED BEFOREHAND)."

As well as come back OUT of failsafe the instant a single valid frame is recived. Keep in mind, that if the signal is bad enough to drive you into failsafe, PPM would be usless. Those who claim "but PPM will still give some control" - well, PCM will do that with every valid frame it sees - it just does not "thrash with the trash" like PPM.

"Because PCM will reject sporadic bad frames without giving any indication to the user (servo jitter) when you range check a model that has a marginal interference problem (RFI from a Gas Ignition System or some Glow Drivers), you would never know you had a problem."

Myth. As PCM starts taking interference, control response gets sluggish due to the discarded frames, and you know that you have interference, WITHOUT having the model go insane, as would be the case with PPM. If you don't notice this in PCM, then you aren't paying attention!

- Tm