Spektrum Glitching - how is that possible? - RC-Monster Forums

10kman · **Spektrum Glitching - how is that possible? -** 09.24.2007, 07:47 AM

So I just got a new Nomadio React, and a Spektrum Micro Rx (Nomadio can read both DSM and the new faster Nomadio mode), and I am amped up, I had SO much space saved with that setup in my 1/18th truck (18t).

Mount the receiver on the sub-chassis brace, run the antenna up a 2 inch long tube, and bind it in my apartment.

Take it outside, and the truck can't get more than like 30 feet away from me before the failsafe kicks in, or it randomly gets some interference and starts spinning out.

I got tired of that after about 2 minutes, and have no idea what is going on.
FWIW, I had the same issue with my other truck, with the Nomadio receiver.

How can I possibly be having interference issues with a 2.4 ghz system? I mean seriously, I thought it was near impossible? As of now, my FM has NO ISSUES, and I can get the truck almost out of sight, and I'm in a dense city.

Pics of how you mounted your Spektrum Micro would be great, or an idea to try, but as of now this new Radio is going to get reboxed and returned in about 2 days. I'm pretty peeved actually, not at the companies involved of course, just the whole situation.

Thanks a lot for any help,

10k

Serum · 09.24.2007, 08:00 AM

have you got another receiver you can test?

anyway you've got some of metal to metal rubbing? (this might lead to interference as well)

10kman · 09.24.2007, 08:42 AM

I don't have another spektrum micro, but had the stock nomadio receiver which also gave me issues.

No metal to metal other than the heatsink on the motor can (Mamba can with an aluminum tube around it).

FWIW - I saw many many pics of similar arrangements in the RC18T series from internet searching, figured I'd be fine.....

lincpimp · 09.24.2007, 09:32 AM

My friend had similar issues with his spectrum products. Most recently he installed a dx2 system in his rock crawler. He had issues until he broke in the motor, guess the new brushes were causing high frequentcy noise?

skellyo · 09.24.2007, 10:53 AM

I wonder if it's a problem due to the Nomadio? I've got 6 different vehicles running Spektrum and have not had a single probelm with any of them.

10kman · 09.24.2007, 04:14 PM

Well here's something that I thought of -

My ESC's in both of these vehicles are Quarks, and I do have the failsafe mode enabled on them. I had it enabled when I was testing too.

I'm at work so I can't test it now, but I'm going to try turning that off and then seeing how it responds. It makes no sense to me though, these things are supposed to be the end all, be all to radios!

Serum · 09.24.2007, 04:17 PM

can't you check if the steering also glitches? take a 2nd person and move the transmitter away from the vehicle..

BrianG · 09.24.2007, 05:05 PM

It might also be that some noise is entering the receiver via the power line (or on a servo line), not the antenna. You could try installing a 1000uF 10v cap on the power and ground lines of the CH3 port, or Y it into the BEC line. It's gotta be close to the RX for best benefits. It might not help, but it won't hurt, and it will help the BEC/UBEC cope with any current draw surges from the servo(s).

MTBikerTim · 09:30 PM

I had issues with my spektrum receivers when I got them at short range. I had to send both back and they were both replaced, along with my mates 2 receivers as well. It sounds to me though more like a transmitter problem with yours. If you have some sort of hump pack and a couple of servos you can test your receivers out like that. That will illuminate anything to do with your cars. I still have issues with my quark 33a esc and having to turn it on and off a couple of times before I get any throttle reaction but once that happens it works fine. I have only once had any sort of glitching and that was just before I hit the low voltage cut-off with my 2s lipo my mini t decided to go awol. I had a runaway, it ended up out of sight and on it's roof. It was stopped when I got to it.

09.24.2007, 09:23 PM

I've the DX2 and with my nitro crt.5 when i'am near of my truck (when i just start it and the truck is on the starter box) the trottle and stearing servo is crazy, goes from full trottle to full brake and steering goes left/right, like if the demon was psses the truck.
But when i'am with my electrique, nothing hapened, all is OK.

One thing that i'am sure, is that this winter i save some money to buy the new Futaba FAST.

MTBikerTim · 09:38 PM

Is that with 2 different receivers david? Cause that is what one of my receivers did and the other was a little better but still had some issues and horizon replaced both. My mates were the same but both of his were just as bad as my first. We ordered ours at the same time from the same place and we assume it was a bad batch of receivers. With my savage you had to be real careful at close range. It would take off without any warning. After it took off and crashed into my mates car I decided that receiver had to be replaced.

The new receivers that horizon sent me both work flawlessly so do my mates.

MetalMan · 09.25.2007, 12:27 AM

I used to use a Spektrum Pro receiver (until the truck it was on was stolen about a week ago), and my range was limited to about 200ft. It's possible the range was reduced by the antenna being about 1/4" shorter than normal. I've heard of people not being able to get more than 30ft. of range with Spektrum systems, so it makes me wonder about Spektrum's QC.

What's_nitro? · 09.25.2007, 12:35 AM

It does say in the instructions for the Spektrum that the antenna length is very specific and should only be altered by an exact fraction (or something like that) so that the tuned circuit inside the reciever will respond correctly to the Tx signal. I've left the antenna on my DX3 system at full length, but if you just want to shorten it so that it doesn't protrude through the body, I recommend just neatly coiling it rather than cutting it. You'll get the same effect of slightly reduced range, but it shouldn't glitch.

10kman · **Update.... -** 09.25.2007, 08:52 AM

Well, long-short, dual failsafes is not a good idea.

Long version -

Got home from work, pessimistic, but was anxious to try out the idea.

I took my large truck, and removed the pinion gear, and placed it in my bedroom with the Nomadio Tranceiver installed. Removed the pinion gear in the event that the radio glitched, I don't want a 15 pound runaway in my apartment.

I stood next to the truck, and started walking away, playing with throttle and steering servo functions. Got about 25 feet away into the hallway, and I noticed a lag in throttle response, and sudden blips, almost like it had my operation queued up.

This was good, I was able to duplicate the issue I was having outside.

So, programmed the Quark on the big truck to have the failsafe turned OFF.

Repeated same test as above. Got same distance away, no issues.

Went to my other room, total distance away was maybe 40-50 feet after you factor in that I was at an angle, no issues.

Same distance, burried the antenna of the Tx into my chest, same functions, I could hear it responding, no issues.

Put the Tx into a glass bowl, no issues.

Pointed the Tx out a window facing away from the truck, no issues.

I was convinced that the ESC's failsafe was the problem.

So, I topped off the batteries, and decided I was confident enough to try it outside.

I stood on the one side of my yard, and drove the truck to the other side of my property and the truck was fine. Precise and responsive.

That's my story. For whatever reason, the failsafe on the ESC was somehow causing an issue with the 2.4 GHz setup. It was fine on the FM band, never had one iota of a problem.

Thanks everyone that threw some ideas my way, much appreciated.

Hope this helps someone else in the future too.....

10k