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Old 01-02-2012, 03:11 PM
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payne9999
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Originally Posted by kyleservicetech View Post
It might be that the switching power supply is radiating electrical noise, and the ferrite rings reduce this effect. But, that radiated signal would also be radiated from the INPUT of the uBEC, so it's a good question. It could send switching signals directly into the battery circuit of a receiver though. I've checked the output of a Castle Creations 10 amp uBEC, and it did have a lot of high frequency electrical switching noise on its DC output. My models have 5 of the CC uBEC's on five Spektrum AR7000 receivers, absolutely no bad issues have ever been observed with this combination.

At any rate, the switching power supplies I've checked operate at below about 100 Kilohertz, and as such might be radiating radio noise up into the IF frequencies of a typical 72 Mhz receiver. So, I'd be a little reluctant to use any uBEC on a low quality 72 Mhz receiver. Not that it might not work just fine, just personal policy.

If you're using that uBEC on a 2.4 Ghz receiver, wouldn't worry about it. No switching power supply can radiate electrical noise any where near 2.4 Ghz. (Thats 2400 Megahertz, or 2,400,000,000 cycles per second!)
I should have said in my original post that the interference issue could be from radiated or conducted signals and the ferrite ring could be used to suppress both.

The thing is the switching frequency is not necessarily the primary issue and it doesn't have to get to 2.4 ghz to cause issues. However, if the rise time of the switching signals is quick enough it will cause a lot of odd harmonics up to and beyond 2.4 ghz. Theoretically it will cause an infinite number of odd harmonics. 1/t = the effective frequency of a waveform and not really it's primary clock frequency.

All this random looking noise can be troublesome and it is hard to predict the effects. If wires happen to be just the right length (like 1/4 wavelength) at one of these frequencies it becomes a very efficient antenna or at some frequency an inductor and the unwanted signals can then cause lots of problems.

Anyway, to make a long story short don't remove the ring, the original designers had a reason for putting it there....

Dave
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