Newbie Question About FM Receiver [Archive]

steeve50

03-09-2008, 09:35 PM

Is it normal that my servo jitter like this when I turn the radio off?

http://www.youtube.com/watch?v=Ll57eUP1EJ4

It may sound stupid but I'm having glitches while in flight and I'm trying to find the problem. You can check my other videos to see what I'm talking about.

http://www.youtube.com/watch?v=JwR0crpV9yA
http://www.youtube.com/watch?v=Y-HCG0ujlTM

First I thought that the belt was ridding of the pulley but I changed my tail case and I'm still having the same problem. And by looking closely to my crash video I saw that one of the servo had a quick glitch just before the crash.

I know I should switch to PCM but as I was reading, it may only hide the problem. So I'd like to fix it before changing my receiver.

DavidH

03-10-2008, 10:27 AM

Is it normal that my servo jitter like this when I turn the radio off?

http://www.youtube.com/watch?v=Ll57eUP1EJ4

It may sound stupid but I'm having glitches while in flight and I'm trying to find the problem. You can check my other videos to see what I'm talking about.

http://www.youtube.com/watch?v=JwR0crpV9yA
http://www.youtube.com/watch?v=Y-HCG0ujlTM

First I thought that the belt was ridding of the pulley but I changed my tail case and I'm still having the same problem. And by looking closely to my crash video I saw that one of the servo had a quick glitch just before the crash.

I know I should switch to PCM but as I was reading, it may only hide the problem. So I'd like to fix it before changing my receiver.

That is usually what happens when using a PPM( FM) receiver in an E powered heli.
PCM won't hide the problem. PCM is not as sensitive to outside RF interference as PPM(FM).
The ESC is emitting RF at times. The belt is discharging a static charge at times, Motor is causing some of the glitches. Just a lot of things going on at the same time that an PPM ( FM ) reciever has problems handling.

David

steeve50

03-10-2008, 12:40 PM

Thanks for the reply, but as you can see on my video. Event if I took of the receiver from my heli and it seems to pick some interference when the radio is turned off. Is it suppose to do that or do I have a bad receiver?

DavidH

03-10-2008, 01:11 PM

Thanks for the reply, but as you can see on my video. Event if I took of the receiver from my heli and it seems to pick some interference when the radio is turned off. Is it suppose to do that or do I have a bad receiver?

Yes there is RF everywhere. An FM receiver will twitch the servos when the power is off on the transmitter. That is normal. A PCM receiver goes into failsafe or HOLD when it does not have a clear RF from the transmitter.

David

EdgeCrusher

03-10-2008, 06:21 PM

Im sorry i don't have a directly related answer to your questions but man did i have BOAT load of troubles with my 450 before i went to PCM with RF/Ring. If you cant get into a pcm setup use RF rings and make sure you have proper electronic placement in the heli. keep motor/esc stuff As much AWAY from radio stuff as you can.

Let us know what you find!