radio channel crosstalk woes

[rccars4sal]

Wondering if anybody else has this happen with some radio gear. Basically,Im getting steering servo interpherence from the throttle. So, when I accelerate forward, the steering servo twitches one way, and on the brakes, it twitches the other. Cant tune it out with mixing .. Turnigy 3xs 2.4ghz transmitter, and matching turnigy receivers.

Im stripping my
favorite runners because this radio system is getting the same problem in every car its installed in.

Is there a fix? caps, diodes, ferite rings? I tried the ferite ring on steering servo lead, no change..

[Incredible_Serious]

Wondering if anybody else has this happen with some radio gear. Basically,Im getting steering servo interpherence from the throttle. So, when I accelerate forward, the steering servo twitches one way, and on the brakes, it twitches the other. Cant tune it out with mixing .. Turnigy 3xs 2.4ghz transmitter, and matching turnigy receivers.

Im stripping my
favorite runners because this radio system is getting the same problem in every car its installed in.

Is there a fix? caps, diodes, ferite rings? I tried the ferite ring on steering servo lead, no change..

I'd be testing transmitter with another receiver, and receiver with another transmitter, see if one or both items are faulty. With it being a 2.4 system, might be also worth checking the transmitter batteries, and maybe even rebinding the tx to the rx....

Good luck!

Alex

[edwin pibal]

what sort of servos ?

Ive been having a lot of troubles with savox servos lately doing the same thing

ed

[rccars4sal]

Ive only got 1 transmitter and 4 receivers for this radio set. So far, 2 of the 4 are un installed. The 3rd is known to be doing the same thing, and the 4th Im not sure because I havent run it in a while. I will try fresh tx batteries, and re binding to see if that helps.

As for servos, just plain futaba standard, jr z590m, and standard spektrum servo thats included with dx7 transmitter. Nothing high current or exotic. Generally I dont get problems from futaba equipment so thats why Im thinking crappy tx, rx , or very noisy ESCs.

[edwin pibal]

I have seen when the amp draw is too great the battery cant supply enough voltage to keep the rx working properly.

and in that case, one of those glitch busters worked a treat

ed

[EvolutionRevolution]

If this is on a brushed electric car, got caps on your motor?

(better ask the simple thing first...)

[rccars4sal]

Well, it took a few weeks, but I got a glitch buster, and no change! Its a brushless setup. Im soo ticked off about it I havent messed with it any more. I need to sit down with several different ESCs, motors, servos,, and start mix and matching to see what is the problem. I think its either the tx or rx(s)

One thing I have noticed on some cheaper(hitech) transmitters is that the steering pot sometimes has some backlash at full throw. So, what might happen is full steering wheel throw will cause the servo to return slightly from end point! Had this happening on a hitech lynx,, and it was also the case on this turnigy tx. I solved that problem by reducing steering throw with end point adjustments.

Current problem with steering glitch is purely emanating when throttle is applied,, so no steering input,, just squease the throttle,, and then steering glitches....

[harvey]

This sure is a weird one. However, I have recently encountered the exact scenario with my latest build. I am using some exotic gear;

futaba magnum junior 75 am
rcd shredder micro receiver
sg-5010 analog servo
quantum reverse knock-off from big-dot-uncle
trinity cobalt 27t motor
installed in a scororpion re-re

The only difference with this install is that I have plugged only the signal wire for the servo into the receiver, with the red and black wires soldered directly to the battery tabs on the esc. This was done to get a full 7.2v into the receiver, to speed it up. I can't say why this is the first time I have encountered the effect of servo twitch upon acceleration, but I thought I'd list my components in case it helps to identify the problem. Maybe a good next step would be to try a separate receiver batt to see if this changes anything?

[jwscab]

try a load test, see if the steering servo twitches if you hold the car up(blocks or stand of some type), with the wheels unloaded. if it does NOT glitch, it is definitely a loading problem somewhere in the power system.

if you have a 4 cell battery adapter, try adding that on the receiver, just temporarily. if you see no glitching, it will double confirm that it's the power system. be sure to pull the esc power wire to the receiver for this test, the esc should generate it's own BEC. some of the cheaper receiver systems have weak BEC systems.

if both tests show that under no loading, or external battery, there is no glitching, then added caps(not stutter stopper) and bigger gauge wire may help on the motor/battery wires. you can add a big cap on the servo red to black wire to help also. another alternative is an external high power BEC.

not sure if you have the esc and steering servo wires lumped/folded/twisted up together, but if so, try separating as far as possible.

lastly, if you have other steering servos to try, see if it follows the servo, might be a 'lossy' servo and sensitive to voltage.

[rccars4sal]

Hi guys, and thanks for the tips. I hadnt messed with it for about a year. I had already done some rudimentary load tests, and with wheels up, the system still glitches. Right glitch under acceleration, left glitch under braking! Its like a badly set up car, pulling different ways under accel, and brakes,, only worse. Havent tried a seperate rx battery, will try that soon.

Sometime last year I switched out the turnigy radio set in a traxxas slash 4x4 to a really old analog traxxas system, and the glitches went away for that model. Unfortunately, the traxxas rx is huge, and so no longer fits inside the waterproof rx box. Also, the ancient traxxas TX lacks adjustments,, but it has been rock solid. Very important on a big heavy fast basher that I let kids drive.

Next tests will be using the turnigy radio set, but with a brushed motor esc setup. I scored some last gen orion brushed motors,, with the round brushes at an angle,, last gasp for brushed technology,, hoping Ive still got a couple novak esc laying around to use.

[yellowdatsun]

My personal experiences with Turnigy products has been crap. I'd get a different radio.

[yellowdatsun]

BUT, I will say, that I've had what I think is cross-talk while driving indoors at the SRS facility. I would *swear* that the car is getting steering/throttle imputs that I am not doing. It happens every once in a while, but it genuinely feels like interference. I run an Airtronics MT4 for reference.

I talked to the guy at my LHS about the Turnigy issues I've had, and they echo the same thing in their experience, which are also bad. One guy even tested their batteries, and the ones labeled 5000mah are actually only around 1800mah. So I still say buy a new radio, but cross-talk does seem to happen sometimes.