Timox

iTrader: (5)

Hi,

I have a glitching problem i just cant figure out and need some help with what i might be able to do to solve it ?

I have a Tekin RX8 speedy in my new 1/8 eMBX6 buggy. I am using a Futaba 3PK 40mhz FM radio with a HRS RX and digital Futaba S9350 steering servo.

Ok so from what i can tell the esc seems to be sending a dirty signal back into the RX and that has cut my radio range in half which is giving me glitching when the car gets about 100ft away. If i put the transmitter antenna all the way down i can only get 3 steps away and it glitches like crazy.

If i unplug the esc and plug in a 6v battery to the RX i get no glitching and i get over twice the radio range. But that's with no esc at all, just steering servo.

Things i have tried:

Different crystals
Different but same model RX - (i have 2)
Twisting esc servo wires
Twisting esc motor wires
Moving RX as far away as possible and on its side
Wrapping esc servo wires in a ferrite ring ( helped a little but no a lot)
Earthling negative wire of esc RX wire to chassis
Disconnecting positive esc wire and trying external 6v battery to eliminate esc BEC

And that's where i have hit a brick wall and ran out of ideas to try.

The only thing that has worked is switching to 2.4ghz but i hate 2.4ghz as i can feel its slower and i still get the occasional drop out or interference from outside 2.4ghz sources so i like FM and plan to stick with it. Too many problems with 2.4ghz that shouldn't be possible but are.

So any ideas ????

kreativedesines

im having the same problem but a little bit worse. i just installed my rx8/t8 combo onto my traxxas e maxx and it worked for a little over 4 minutes, then i went out about 50-60 feet and it started glitching so i brought it back closer. then i charged my batteries. now whenever i try to plug in my batteries and turn on my rx8 it gets alot of radio interference and starts going crazy. this happened and it took off into a wall and snapped 2 a-arms and a steering servo. this is a really big inconvenience because i want to drive my truck so bad, but every time i do it just takes off. oh, and im running a traxxas tq 27.045mhz FM radio. does anyone know what i can do to stop this problem.

bshack

iTrader: (2)

Try plugging a capacitor in your receiver.

Timox

iTrader: (5)

Did that ( forgot to mention in original post ) And it did nothing.

G33Kster

iTrader: (11)

I have heard of this problem before, and it seems to be a characteristic all FM radio systems share. It doesn't happen with AM or 2.4GHz to my knowledge, so may have to consider going for one of those. You could also try putting a Faraday cage around each of your electronics

Timox

iTrader: (5)

I think the ESC is injecting the receiver with interference directly through the cable that connects them both together ???

I also forgot to mention i have tried a Opto isolator and external BEC but the opto didn't work with the Tekin as the Tekin could no longer sense there was a incoming radio signal so couldn't find neutral .

I didnt want to go back to 2.4ghz. Been there done that and didnt like it. I like the feel and speed of my HRS crystal based system which is supposed to be the fastest system avaliable and i could eaisly feel it when going from using 2.4ghz for 3 years and going back to the crystals with Futaba HRS enabled.

G33Kster

iTrader: (11)

I think what is happening is (going to get a bit technical here) that the frequency at which the ESC operates closely matches or is a factor of the frequency of your radio system. Because of this, when your motor is receiving power from the ESC, it is outputting electromagnetic waves at the ESC's operating frequency. Because the RX8 is such a high-power system, the range of the waves is greater than others would be. These waves are inducing current into your signal wires and antenna, therefore adding "extras" and glitches into the process.

Timox

iTrader: (5)

Hmm. Ok but what about when the car is in my hands and i leave the transmitter on the bench and i start walking the car away from the transmitter and get 5 steps and it starts going crazy by itself ? So no motor running and no manual input from the transmitter ?

I just seem to have a shortened radio range. So when i get 5 steps away it goes out of range ? This is with the transmitter antenna down of course. I get about 40 steps away with it fully up.

I have had it happen also with a JR R1 radio also on 40mhz FM and a Novak brushless 1/10th system.

I also have a Speed Passion 1/10th brushless setup that I don’t get this problem with the same Futaba radio so it seems ESC specific ?

G33Kster

iTrader: (11)

Now that I cannot explain. Anybody else on this forum know what's going on?

pooter2586

iTrader: (10)

Mine was doing the same thing after installing the mamba monster in my buggy and ended up installing a 2.4 radio and everything works great now.

SNIPR

iTrader: (12)

I have heard that FM & Brushless setups just don't get along. I have a Futaba 3PJ FM/PCM radio that I used in my brushless SC10. I had an issue with the antenna mount, so I used a full long length one and it seemed to have fixed it. I was using Mamba Max / 5700kv setup. I had another issue when I put it on the track and walked away it would get interference. So I walked closer to the SC10 and it stopped. I didn't change anything and it just started working fine. No interference after that?

If you can try to pick up a FM/PCM radio and see if that helps out. I am putting together my 1/8th Truggy running RX8 setup and will see if I have issues with that. If I do, I will most certainly have no choice but to switch over to 2.4ghz...

wjmiller3

iTrader: (9)

My Slash 4x4 was doing the same thing, bought a 2.4 radio and everything works great now.

JSR

iTrader: (18)

I've had similar interference issues with both AM and 2.4GHz systems. 2.4GHz systems are less prone to noise, but aren't immune from them. I believe what G33Kster is saying is the most likely scenario. Even though you're not applying throttle, the ESC is still operating, which means it still has a switching frequency. That frequency happens to have a harmonic that's the same as your radio setup and is strong enough relative to the radio's signal to make false signals. The reason it gets worse with range is because noise is relative. The smaller your actual signal gets, the smaller the gap between the signal and noise and as that shrinks, the noise eventually gets recognized as a signal. There's even more noise that gets introduced by the mixing of the frequencies, but that gets complicated...as does whether the noise is being injected via radiation or conduction. Certain ESCs and radio systems just don't get along. I know that the Tower/Tactic 2.4GHz systems do not seem to like Hobbywing 1/8-scale ESCs (both the old big Ezruns and the new Xeruns), but are ok with other systems. Your best bet is to switch to another type (doesn't matter which type...AM might work even) of radio system. Giving that a shot would at least eliminate or confirm the theory.

Timox

iTrader: (5)

Ok so i guess i am not alone on this one. Yes 2.4ghz dose fix it but i like the speed and reliability of FM. I have had problems with interference from 2.4ghz in the past and drop outs that doesn't happen with FM unless someone is on your channel which these days would almost never happen with everyone on 2.4ghz.

Haven't tried PCM or AM as i don't have anything on those bands.

It is looking like i might have to give in and fold to the 2.4ghz but only if i can find one that is fast enough and feels like my crystal radio and is super stable and reliable ???? Cost no object when it comes to reliability and precision. KO Eurrus ???

G33Kster

iTrader: (11)

I use the stock AM 2ch. radio system on my Evader with no problems at all running a Sidewinder combo- you might want to consider AM if you can't find a 2.4GHz system that you like.
Also +1 to JSR for the great explanation