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RF shielding on esc throttle cable?


Edgeflyer
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Is it still important,with 2.4ghz, to have the throttle cable from the esc twined in and out of a ferrite ring ?

Presumably this prevents RF escaping from the current flowing there? But we don't shield motor wires or servo leads so is it necessary?

The ring is a pain in small model installations so can I get rid of it?

 

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Be careful. The ferrite ring is intended to filter out high frequency 'rubbish' from not only the ESC circuitry  but also the switched mode BEC. It's not so much 2.4 V 35, but unwanted noise getting into general non RF stuff like servos and decoders and possibly causing problems. Test thoroughly before making any changes.

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1 hour ago, Edgeflyer said:

Ok thanks. Maybe I will try on a cheap plane. I don't understand how servos can be affected by "rubbish" as they take their input from the receiver via cable not wireless. Anyway most of my crashes are due to rubbish piloting!

It's more that the long servo cable acts as an aerial, the position signal is quite a weak signal, so any stronger electromagnetic field could corrupt this signal, same with the electronics in the receiver/servo. So while highly unlikely it's not inconceivable, it would also depend on if the ESC has been designed and tested not to produce electrical "noise". https://oscarliang.com/ring-esc-ferrite-ring/

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10 hours ago, Edgeflyer said:

Ok thanks. Maybe I will try on a cheap plane. I don't understand how servos can be affected by "rubbish" as they take their input from the receiver via cable not wireless. Anyway most of my crashes are due to rubbish piloting!

 

Cheap planes can still cause damage to something or somebody..........

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Can't remember where but years ago I read or was told that on 2.4 they weren't needed so have taken them  all off off after that, having said that I can't remember the last time I actually removed one as many now don't seem to fit them anyway. I don't think Jeti, Dualsky or YGE fit them on their controllers anymore (I stand to be corrected on that though). Now these would all be opto controllers with no BEC's though.    

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I remember reading an article on this issue but I cannot remember which mag it was in.  The writer said that most of the metal to metal noise, and all the other noise that is generated in a model is limited to 300 MHz.  So, as with our current operating frequency of 2.4 GHz, we hear nothing or rather our Rx hears nothing of this noise that jiggered up 35 MHz Rxs.

 

I certainly have had no problem with any interference on my radio (JR XG series on 2.4 GHz) or on my ESCs.  The ESCs have mostly been Jeti Spin 99s although I have used a Spin 75 as well as one or two others.  The current flow on my 10S set up is around 80-85 amps at max power and that has never caused a glitch either.  So, it seems to me that the huge benefit of 2.4 GHZ is that it sits well out of the "up to 300 MHz" noise generation area and is so immune to it.  Certainly seems to be borne out by user experience or rather lack of experience of electrical noise causing a problem.

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On 25/07/2022 at 10:43, Edgeflyer said:

Ok thanks. Maybe I will try on a cheap plane. I don't understand how servos can be affected by "rubbish" as they take their input from the receiver via cable not wireless. Anyway most of my crashes are due to rubbish piloting!

If an ESC or BEC is particularly noisy from an electrical point of view then the wiring is an ideal conduit to directly distribute the 'rubbish' thoughout your system. I've had this with a particular brand of cheapy servo that was  affected in this way with only one type of ESC.

Have a look around your home at the multitude of separate small switching power supplies that come with DVD players, portable TVs etc etc. Some will have a ferrite choke on the cable that plugs into the main device to filter out noise and spikes from the PSU.

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