R148DP Question
09-10-2003 | 03:16 PM
#1
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R148DP Question
Hello,
This morning I replaced the R148DF with a R148DP in my 29% Edge 540. After discovering that I had to turn my transmitter off after changing the modulation between PPM and PCM I was able to make things wiggle on the plane from the transmtter. So far so good. While making things wiggle I could tell that the controls were not moving smoothly. It was like I could see the steps as the servo moved across its full range. The servo's speed also seemed to have dropped. As this is my first large model and my first PCM receiver I am concerned by this.
My work shop is very RFI noisy and my PPM receives all chatter a great deal when I am doing anything with the radio. I am hoping that these symptons are nothing more than this RFI noise causing some updates from the transmitter to be lost and that caused the servos to move in large steps. Also, I don't yet have any failsafes programmed. Does this sound about right? I will of course thoroughly range check this new receiver at the field before flying...
This morning I replaced the R148DF with a R148DP in my 29% Edge 540. After discovering that I had to turn my transmitter off after changing the modulation between PPM and PCM I was able to make things wiggle on the plane from the transmtter. So far so good. While making things wiggle I could tell that the controls were not moving smoothly. It was like I could see the steps as the servo moved across its full range. The servo's speed also seemed to have dropped. As this is my first large model and my first PCM receiver I am concerned by this.
My work shop is very RFI noisy and my PPM receives all chatter a great deal when I am doing anything with the radio. I am hoping that these symptons are nothing more than this RFI noise causing some updates from the transmitter to be lost and that caused the servos to move in large steps. Also, I don't yet have any failsafes programmed. Does this sound about right? I will of course thoroughly range check this new receiver at the field before flying...
09-10-2003 | 04:15 PM
#2
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RE: R148DP Question
I'm not the manuf., but I'll tell you my experiences....
I've used both PCM and PPM and the only difference I see on my planes is the perceived noise immunity in PCM (the bad signal packets are discarded, thus shutting down the channel while the signal is interfered with when using PCM, rather than the servos jerking around such as when using PPM), and the failsafe.
I have not noticed any problem with jittery servos, etc. unless like you, I am in a noisy environment.
Since you do have a shop with excessive RFI, you may have hit on the problem. Try it at a different location and see if it gets better.
Good luck!
Sean
I've used both PCM and PPM and the only difference I see on my planes is the perceived noise immunity in PCM (the bad signal packets are discarded, thus shutting down the channel while the signal is interfered with when using PCM, rather than the servos jerking around such as when using PPM), and the failsafe.
I have not noticed any problem with jittery servos, etc. unless like you, I am in a noisy environment.
Since you do have a shop with excessive RFI, you may have hit on the problem. Try it at a different location and see if it gets better.
Good luck!
Sean
09-12-2003 | 09:48 AM
#4
My Feedback: (11)
RE: R148DP Question
Sean basically said it. If you are in a noisy RF environment, then the signals that do "leak" through would cause problems in the decoder. It would freeze operation for a second or so and then unlock if good information comes in. If the interference persists, then the receiver would stay in lockout or move the servos to your pre-programmed failsafe positions.
You'll have to try the system in an area that doesn't have so much RFI.
PCM is not interference proof.
You'll have to try the system in an area that doesn't have so much RFI.
PCM is not interference proof.
