found the glitching issue, need help solving it
 

Ok, so I have a cap on ch3 on the receiver, and I still have glitching. I think I know what the problem is but I wanted to see how I can solve it.

I run 9xl, 9920 esc on 5s 6000 and when it gets about 50 feet from me it glitches if I'm hard on the throttle. When I put in my 4200 Ib 7-cell, I can have full throttle and go far away, no glitching.

So, it seems when I have the 5s that either the esc can't keep up, or I'm loosing juice.

Any ideas how I can solve this?

Also, less then 50 ft, with 5s, I can not get it to glitch, even full throttle.

So, more then 50ft, on running 5s is the only time it happens. When I run it in 1st gear, it doesn't seem to glitch, so I'm thinking it is starving for juice.

Just to make sure that we have all of the facts. Are you running an external bec, with the internal bec disabled.

BTW, I believe that all the cap in the 3rd channel does is to help to compensate for the voltage drop of the battery, so that the radio doesn't shut down. It really doesn't help much with a lipo pack. It isn't going to stop radio interference.

The only thing that I can figure is that you are pulling much more current when running the lipo pack so there is more interference.

Try moving the radio farther away from the motor and esc.

Yes, I'm running an external BEC.

I have the receiver up front, and the esc in the rear, I can't really move it anywhere else. Should I try moving the antenna?

Remember, near me it works fine, no problems at all, in fact I had my friend hold it in the air, and I held it at full throttle with no problems, it is just when out 50 ft or so, which drives me crazy.

If it was the receiver, would it cause issues up close?

I guess not for sure, maybe your Ext UBEC has EMI or EMF problem.
what receive you have?

Try to use 6V receive battery to find out your problem.

You will usually get less glitching up close because the radio signal is stronger. Is the antenna wire near the motor or power wires? Those high current wires, especially the motor wires, can emit RF noise which can cause problems with some radios, especially AM.

The cap in third channel will simply even out the U/BEC voltage so there are less dips under load. It can also help filter out noise coming down the BEC wires.

Here are some pics, let me know if you think I need to move anything.

Front, receiver and BEC

Back, motor and ESC

I have a Futaba 3PM-FM, with Futaba R203HF 3-Channel FM 75MHz receiver.

I like the idea to remove the BEC to test, I think I will try that.

In case you remember, my wire was cut on the receiver, but in another thread someone suggested I opened it up and solder a new Futuba wire to the board (which I did). I had thought that was going to fix it, but I get the same results, I did gained 10 feet or so but the problem still exists.

If the red thing between your servo and RX is your BEC, I would move it back to where your ESC is, switching are good but they can me quite noisy.

your receiver is R203HF HRS Digital system.
and i look your servo is bluebird MG6xx right?

I think 9920 maybe not compatibility HRS mode?

if so, try change R113ip PCM receiver.

hope this help.

Correction, I just looked, my owners manual talks about the r203, but mine is actually Futaba R153F 3-Channel FM 75MHz.

I do have the bluebird BMS-660MG servo as well.

Yes it is the bec, I will move this to see if that helps.

I've never had a bluebird servo, but I have seen some other inexpensive servos with good specs. They had ALL metal gears in them. Metal on metal gears can cause radio interference too.

sorry i forget 3PM not PCM mode.

but i think , complete remove ubec and try use 6V receiver pack first.
sometime BMS-660MG servo need more AMP for driver.

I've heard that too, but isn't that generally for AM? I would think FM would be out of range of gear noise frequency-wise...

Brian, I don't know. You know that I don't know any of that technical stuff. I just know that I've seen FM radios do some pretty freaky things too. It was just a thought.

Hi, Try turning the UBEC over. With the board turned toward the motor and wires should block more interference.

FM and AM are in the same carrier band, both are susceptable (sp?) to mechanical vibrations. This is supposed to be the advantage of the newer 2.4GHz systems.

As for the problem. does you antenna wire run under the chassis and then up through the antenna mount? Is the receiver padded from the aluminum chassis? I am with the guy above who suggested trying a regular receiver pack once to see what happens. be sure to remove power from the Ubec when you do this experiment.

That is true, but AM has the actual signal modulated on the top of the carrier frequency, which is the worst place to be noise-wise. FM shifts the carrier frequency by the signal amount. Also, FM [should] chops the top and bottom on the carrier wave. These together help eliminate a lot of RF noise. But if the noise (or harmonics) is close enough to the radio frequency and is powerful enough, FM still suffers. But AM is worse to be sure. Granted, I am assuming AM and FM radios work like regular radios (the music kind).

Aside from the 2.4GHz systems being at such a high frequency, the radio and receiver employ error correcting in the digital packet transfer (at least in the ones I am familiar with). Both of these together make for a very reliable link.

I did a test yesterday, and moved the BEC away from the receiver, and behind the tranny. The glitching was the same, and if I lowered the radio, it made it worse, and the distance was only like 30 ft.

When it was near me, no problems at all!

Here is my plan, since I have the Futaba 3PM-FM I feel I have to stick with FM, I really don't want to pay for the switch to 2.4 GHz.

So, I'm thinking of getting a new receiver and digital servo:
Futaba R203HF 3-Channel FM 75MHz Rx
Hitec HSC-5955 (I'm assuming this servo will work fine with this setup)

Do you think this will solve the problem? My BMS-660MG has metal gears, and a heat sink, which may be causing the interference.

Plus, isn't digital servos better?

If I can do this to solve this problem, then I would be happy. I do believe the 2.4GHz system would fix this problem but I'm not sure I need to go to that at this point.

did you try using a regular receiver pack?? or moving the antenna and receiver off of the metal chassis? These are free things to try before replacing parts that may not be the problem.

No, but I should. How would you move it off the chassis, just put it on plastic?

BTW, I had this problem with the plastic chassis, with this new setup (I rebuilt the entire truck last weekend) I moved the ESC far way from the receiver. I should still test it without the BEC and maybe move it away from the servo to see if that helps.

May not help if you saw it with the plastic chassis. You can still try it though. Mount it on some foam padding or something that can absorb mechanical vibrations. Also, try to route the antenna wire so that is does not pass through the metal chassis. You can always make a small hole in the side of the antenna tube and get the wire in that way. Be sure to keep the receiver and antenna wire aways from battery and motor wiring. Your antenna is very close to you battery pack. Just for kicks, you could temporarily more the antenna tube to the shock tower and stin the receiver around so that the wire end of the receiver points toward the shock tower. If you are carefull you could also move the receiver to the shock tower as well to keep it away from everything.

I would still suggest trying the regular battery type receiver pack once just to see. It will help rule out the possibilities.

Be careful when moving to a HiTec digital servo. I have seen them fail in very strange ways. My friend had one die at a national level sedan race. He would just randomly get severe gitters and then it would go away. It turned out to be his HiTec digital servo!

Keep us informed.

Which servo would you recommend, if I end up doing that?

I will move the antenna and receiver to see if that helps, good ideas!! I can also slide the battery pack back some, which I will do too, as well test with a receiver batt pack.

Thanks again, I will keep you posted, it would be good to figure this out.

Try install a toroidal core on your ESC's receiver wire. If that's too much effort, try one of these.

Oh, and ensure your crystals are properly seated!

After some deeper thought, before spending money do that range check with your receiver removed from the model, and only one servo and power plugged into it. If you get the same glitching your receiver's and/or transmitter's center frequency has probably drifted and you need to:

* Get (a) new crystal(s).
AND/OR
* Send it/them in to be recalibrated.

If you are going to get a new radio, perhaps you should consider something other than FM. When we first put my buddy's 8ight together, he opted for a JR XS3 (I think) FM modulated system. I don't know what it was because we could never get rid of the glitching. He went and traded it in on a Spektrum system and all troubles went away.

Just some food for thought.

All I know is that I have NEVER had any glitching problems with the Spektrum. As a result, everything I own is Spektrum. As soon as that new 30-model-memory comes out, I'll pick that up and sell my DX3 and DX3.0 transmitters and rebind the receivers to the new one...