Frsky rb35s with kst bls815 servo jitter

[ErikBoom1981]

Hello,
I am using a rb35s with 2 TD mx rx's and kst bls815 servo's . The problem i'm having is that in the channel 1-9 output they jitter like crazy not just at center both bec outputs are set to 8,4 v (also tried with lower voltage with no change ) in the bec 2 outputs this doesn't occur so channel 10 til 24 . What am i missing here?

 

[HENNY]

Hello,
I am using a rb35s with 2 TD mx rx's and kst bls815 servo's . The problem i'm having is that in the channel 1-9 output they jitter like crazy not just at center both bec outputs are set to 8,4 v (also tried with lower voltage with no change ) in the bec 2 outputs this doesn't occur so channel 10 til 24 . What am i missing here?

These jitter issues can often be tracked to the receiver telemetry getting into the signal wire of the servos. ensure the receiver anteenas are well clear of any servo wires may solve your issue. You can also reduce the Telemtry power output from 100 mili watt to 25 mili watt

 

[ErikBoom1981]

I tried both things also completally turned telemetry off ,but the issue remains ,weird thing to me is that it only happens in the bec 1 exits channel 10 to 24 doesn't have the jitter

 

[jure]

The receiver may be overlooaded with RF signal. Try placing the transmitter and receiver farther away

 

[Wayne]

Please try another servo and see if you still get any issues.

At first I thought you had the FrSky BLS servos and then it would be easy to adjust the programming of the servo, but with the KST don't think there is an option. They do have a programmer, so maybe. Never heard any reports of RF noise on a KST, it is simply not an issue. I'd be shocked if it was shown to be radio noise.

Is it just noise, or actual movement? The KST servos have a VERY low deadband, thus more noise. Wondering if there are any settings in the RB-35S to help with this.

 

[ErikBoom1981]

Sorry for the late reply , i tried with a cheap servo and it doesn't have the issue ,also it is not just some buzzing around center it is when you get to roughly 3/4 of the way of the trow in both directions that it starts to move back and forth a quite a bit specially if you keep it at 3/4 of the way , i'm almost thinking it has something to do with the stabilizing (even if i have it turned off ) seeing that it only happens in the first 9 channels (the ones of vout 1), Also tried the KST servo's on a normal reciever without the rb-35 and they work perfect no weird movements

 

[bipestick]

I am having the same issue with a TD R18 and a TD R10. I talked to FRSKY, in California and they said it is the 900 MHZ telemetry interfering with the servos. Move your 900 MHZ antenna around when the radio is on. If you find a spot that it stops then it will confirm the issue. I have tried different servos and found that the issue goes away. Not happy to have to replace 12 servos with ones that are compatible. I was using King Max servos from Gator RC. I found Hitec and Savox servos seem to work so far. I'm still exploring what will work best. Seems not all servos are the same. Good luck.

 

[Wayne]

Some servos are very old designs, so not too surprised. Many popular mid priced servos were designed prior to telemetry receivers were a thing. Something like the KST BLS line is pretty darn new and should not have an issue with this, but then again, 900 band telemetry is not all that common even today.