Frsky problem.

[mr.sneezy]

Hey does anyone have an old school logic analyzer kicking around ?
A logic analyser can capture a long sting of the PPM train from the RX servo output (one or many channels) and then allow a close look at it, pulse by pulse. That may be of help, if done while moving the TX sticks fast.
I think some decent CRO's can do this too in a limited way.

Martin

[Fly2High]

Bruce,

I was wondering if you could go back and retest the smoothness of some of the other module based systems that were reported as being notchy. I ask because is it possible that the choice of servo, as is being seen with the FrSky system, could have something to do with it?

I am just curious if some systems will also become smooth with different servos and notchy and stepped with others.

Could they be better than frSky right now with the ones that FrSky is stepped/notchy with?

(I really like what FrSky is offering but the devil's advocate in me suggests that maybe more testing of the other units might be nec. based on this issue)

Could it be that another good system that was reported as being not so smooth but as good as FrSky might also be good if different servos are used or whatever the solution is found for here, could be used there as well?

Frank

[peso]

Assan X8 is not so smooth either. Expecially not with the HXT900 servo. Much better with a slow standard servo.
/PO

[RCModelReviews]

I tested all the radios with digital (Savox) and standard servos.

I'll take another look though.

FHSS systems (even FASST) will always have a tiny amount of "jitter" due to the fact that there is hopping going on but normally this falls just outside the deadband of most servos (especially standard servos) so doesn't usually produce a problem.

I' won't get a chance to do any testing until tomorrow unfortunately.

[jet760]

Hi bruce
I have noticed when using the frsky module on my JR 9X11 the LCD sceen flickers a little have you seen this? and what could be the problem. The fm and Spektrum modules don't do this.
David

[RCModelReviews]

Can't say I've noticed it -- but I rarely us my JR9XII these days -- preferring (gasp!) the FlySky 9X -- so that when I drop it I won't cry

I'll check tomorrow for you and see if I spot any flickering.

[JMP_blackfoot]

Good thinking...
I've got an Optic 6 here with shift-select -- I'll compare +shift to -shift and see if I can spot a difference.
If there is a difference then a simple inverter should go a long way to solving the problems with some DIY installations.

In a past life, I designed and sold a receiver (under the brand name JMP) which at first wasn't autoshift. Then I made it autoshift by simply reducing the value of the input coupling capacitor to the squaring stage after demodulation so that it would differentiate both edges. There would thus always be a pulse of the correct polarity. That's when I became aware this business of leading edge/trailing edge...
Could you by any chance have a look and check for jitter of the pulse width?

[RCModelReviews]

Is that a question???

I'll be looking ASAP

[takilara]

BTW just for information.
I've now tested both heli's with the FrSky Two Way Rx and V8 Rx.
Both seem fine and smooth in the air. (though the choppy behavior became much less when reversing polarity of the ppm in the Tx menu)

The softstart on the Trex 600, didn't work very well though. I am investigating this, I don't necessarily think this have anything to do with FrSky, but it might confuse the esc if the pulses are "jittering"

On the small heli with the V8 Rx, i seemed to notice the heli "hesitate" if i rotated from one side in to the other side in, the heli would "pause" for a split second when the tail was pointing straight towards me.
I assume this has something to do with my antennae placement, and the Rx switching antenna or something when the tail is pointing towards me. I don't think this has anything to do with the choppy behavior we have noticed.

[Fly2High]

What is the latest word?
Is it still an issue?

Does it only affect certain servos?
Which ones?

Has there been any firmware upgrade to correct this?

thanks

Frank