[NSRCA-discussion] ESC and RX intereference

Thu Aug 10 08:48:42 AKDT 2006

Dean,

  Excellent description!

  If there is an opto-isolator internally, then the obvious solution would be for the ESC manufacturer to include the fiber-optic link to the receiver.

  Fiber optic servo extensions here:
  http://forgues-research.com/page3.html
  These are primarily intended for isolating ignition engine throttle/choke servos, but should also work for ESCs.

  I wonder how much could be done to mitigate the EFI by shielding the motor and battery leads?

  Bob R.

Dean Pappas <d.pappas at kodeos.com> wrote:
      Hi Gang,
  The real fix (or at least part of it) is a cheap plastic optical fiber link. The folks at Smart-Fly (the obvious website) created one, and the market didn't materialize. I have a prototype, but a 5V supply at the ESC end will have to be created that runs from the big battery. Maybe the microprocessor supply on the ESC can be tapped for the optical receiver. The problem, even though all these ESCs are opto-isolated, is that the ESC/servo lead is still an antenna that runs deep into enemy territory, picking up motor and ESC induced crud and putting it into the RX ground. That corrupts the receiver's measurement of the received signal. Dave's ferrite donut helps this. The biggest sources are the big battery leads, and the three motor wires. The big battery wires should be twisted, or at lest tied together so that any AC current ripple in those wires does not have a big loop antenna with which to braoadcast magnetic noise fields. Those big capacitors on the input of the ESC
 do not completely flatten the current coming from the batteries, and in particular the big caps used are useless at several MegaHertz . 

  The same is true for the three motor leads: they have 35 volts of square wave AC with lots of current. Both the electric and magnetic fields are considerable, but if short and twisted or tied together, they become less effective radiators of RF. OIf course, distance is king. The optical link woiuld then allow you to keep any radio wiring far from the power system.

  An electronics hobbyist could build a cheap fiber link with maybe $20 in parts from Digi-Key. 

  Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 
    -----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of DaveL322 at comcast.net
Sent: Thursday, August 10, 2006 11:04 AM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] ESC and RX intereference

  With my Abbra, I had throttle glitches (but no radio holds) and no amount of re-routing wires or antenna helped.  3 different RXs made no difference (2 770s and 1 649, all SC JR).  Adding a choke (the iron ring thingy) to the ESC lead immediately adjacent to the RX fixed the problem.  Of note, ESCs used were CC Phx 45 and 85 and the glitching did not occur with setups that were <55 amps.  I've now run up to 85 amps no problems.

  I had the same thing with my Prestige - throttle glitches but no radio holds.  The same choke helps, but wasn't a 100% fix.  Rotating the RX 90 degrees (in any orientation) had an effect, so I picked the "best" orientation and only an occasional throttle glitch remained.  I recently changed from the 770 to the 790 (synth SC) and that is better still (99.9% fixed).

  Regards,

Dave Lockhart
  DaveL322 at comcast.net
  Team JR
  Team Castle Creations

  -------------- Original message -------------- 
From: Chad Northeast <chad at f3acanada.org> 

> FWIW, I have an identical equipment setup as Adam, even placing of the 
> gear is near the same. We built the planes together, use the same 
> paint, covering etc. The only difference is I use Futaba radio gear 
> (9Z, R319DPS rx)...and have never once went into hold. I think we came 
> to the conclusion that there is something going on with DC rx's and how 
> they filter out noise vs. SC rx's in some setups.....as both our setups 
> on DC work great, and Adam's on SC did not. 
> 
> Maybe someone with a bit more EE knowledge could explain why this would be. 
> 
> Chad 
> 
> Adam Glatt wrote: 
> 
> >I'm forwarding the conversation I had with a pattern buddy to the list 
> >in the hopes! it wil l save someone else's airplane. 
> > 
> >Adam Glatt 
> >Team Shulze 
> >Team Plettenberg 
> > 
> >-------- Original Message -------- 
> >Subject: Re: ESC and RX intereference 
> >Date: Wed, 09 Aug 2006 21:38:14 -0600 
> >From: Adam Glatt 
> >To: 
> >**** 
> > 
> > 
> > 
> > 
> > 
> >Yikes, that sucks. 
> >I was going into hold about every tenth flight with my Mantis (Xtra 
> >25). When I switched to the Twister I was going into hold about three 
> >times a flight (EVO). I tried everything (new TX antenna, new TX 
> >module, new TX crystal, new RX crystal, new RX, twisting elevator servo 
> >leads, choke on ESC line...). The only things that helped were running 
> >the antenna along the wing, and switching to a JR dual conversion 
> >receiver. ! Since s witching to the DC RX I've never had a moment of hold. 
> >This electric motor stuff is definitely causing interference with the 
> >RX. It is very important to set your failsafe to have the throttle go 
> >to idle. This way, when it goes into hold, it will chop the throttle, 
> >which ends the interference. I also set my failsafe to deflect the 
> >rudder a bunch so it is very obvious when hold is occuring (good when 
> >trying to sort out the problem, bad when trying to compete). 
> >I'm betting your only solutions are switching to Futaba or Hitec TX+RX 
> >systems, or using a vastly different receiver: JR DC, Berg 7 (just 
> >released), Sombra Shadow, GWS... 
> > 
> >I have a spare ch48 JR DC RX crystal that I can send you, and I can sell 
> >you a Sombra RX through work. Other than that you'll need to source 
> >your solution elsewhere. If you want to try ! the Ber g 7 I suggest 
> >phoning Castle directly, as no dealers have it yet. 
> > 
> >It's also possible that a different brand ESC will fix it. I can sell 
> >you an HV85 through work for cheap. 
> > 
> >I've been down this road. The EVO + Schulze system interferes with 
> >something in the JR SC PCM receivers - that much I'm sure of. 
> > 
> >-Adam 
> > 
> >******* wrote: 
> > 
> > 
> >>Hello Adam, 
> >> 
> >>I had a problem with my radio yesterday and I want to check with you 
> >>since it maybe the same cause as you. 
> >> 
> >>I was trying the Evo for the first time yesterday evening at the field. 
> >>I range checked before the flight but not with motor running. That may 
> >>have been a big mistake now that I think about it. Anyway the flight was 
> >>fi! ne unti l I got to the horizontal 8. Just past the middle of the first 
> >>loop down, the motor stopped and the control went to neutral. The plane 
> >>was going down inverted at about 45 degree and hit the ground. I tried 
> >>elevator and ailerons with no success. Amazingly, the wing, batteries, 
> >>ESC, motor are fine. The prop just folded, the wing didn't come off but 
> >>the aileron servo gear stripped. The other servos works ok. There are a 
> >>bunch of cracks in the fuse but I put everything back in place with CA 
> >>and tonight I will put some glass and carbon fibre inside. I rechecked 
> >>the range after the crash, checked all connections and can't found 
> >>anything. My transmitter is a 10X with the synthesizer module. 
> >> 
> >>My friend ***** told me the ESC may have cause the fail safe condition. 
> >>The motor was back ! to low throttle before the fail safe happened. You 
> >>say in the message below that you had interference this year. Was that 
> >>only with the Evo and its ESC ? I had 122 flights with the std 30-10 and 
> >>ESC with no problem at all with the R770 and the R2000 since around the 
> >>middle of Jul. I was planning flying tomorrow with another TX & RX if 
> >>the plane was ready but now I am thinking of checking the range with the 
> >>motor running before going to the field again. 
> >> 
> >>What do you think ? 
> >> 
> >>****** 
> >> 
> >> 
> >> 
> >> 
> >> 
> >>>-----Original Message----- 
> >>>From: nsrca-discussion-bounces at lists.nsrca.org 
> >>>[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Adam 
> >>>Glatt 
> >&! gt;> Sent: July 4, 2006 11:10 PM 
> >>>To: NSRCA Mailing List 
> >>>Subject: [NSRCA-discussion] WTBuy or WTBorrow: JR Dual Conversion 
> >>>receiver crystals (red) ch48 and ch30 
> >>> 
> >>> 
> >>>I've been having nonstop radio interference problems this year but 
> >>>finally solved it by installing a JR dual conversion PCM receiver. 
> >>>However, I don't have receiver crystals for this receiver on the 
> >>>channels I'm set to fly in Muncie. I need the red JR dual conversion 
> >>>receiver crystals in channels 48 and 30. I'll buy them or borrow them 
> >>> 
> >>> 
> >>> 
> >> 
> >> 
> >> 
> >>>during Muncie. 
> >>> 
> >>>-Adam 
> >>> 
> >>> 
> > 
> >________! _______ ________________________________ 
> >NSRCA-discussion mailing list 
> >NSRCA-discussion at lists.nsrca.org 
> >http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 
> > 
> > 
> > 
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