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Ferrite bead filters...when and where????

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Old 07-23-2004, 08:59 PM
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Capt Jim
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Default Ferrite bead filters...when and where????

Can someone describe the proper use and installation of these ferrite bead filters. I've heard a lot of flight line chat, but I'd really like to hear from someone who knows the technical end of this subject. Some guys would have them all over...like christmas decorations.....where, and under what conditions, do they really provide a benefit?
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Old 07-23-2004, 09:22 PM
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mr.rc-cam
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Default RE: Ferrite bead filters...when and where????

This fellow is not impressed with the bead-donut trick: http://www.rcgroups.com/forums/showthread.php?t=255221
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Old 07-24-2004, 09:43 AM
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Default RE: Ferrite bead filters...when and where????

Thoughts below from someone in the know with accurate empirical testing and real world results....

I do not recommend them. Unless configured for your particular installation circumstances (there are hundreds to choose from - based on operating frequency, line length, and specific noise concerns) they are ineffective. They will however slew the O/P signal, in some cases making it difficult for the servo to respond properly due to severe edge-rounding of the signal O/P.

In every case where the ferrites were installed to deal with perceived anomolies (installed whether there were issues or not), the ferrites themselves caused communications issues that cleared up when they were removed.
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Old 07-26-2004, 10:58 AM
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Default RE: Ferrite bead filters...when and where????

For some tutorial information on the use of ferrite beads go to www.fair-rite.com

I would say avoid them unless you have a known EMI problem. Using them to prevent anticipated problems is a real shot in the dark and may introduce new problems.
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Old 07-26-2004, 02:31 PM
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Default RE: Ferrite bead filters...when and where????

Mglavin is correct. They serve no usefull purpose in the way we set up RC planes other than possibly create one more place that can cause problems.
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Old 07-26-2004, 09:08 PM
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Capt Jim
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Default RE: Ferrite bead filters...when and where????

Apparently, from what little I hear locally, they are being employed in an attempt to reduce ignition interference from gasoline motors, and also to protect against unwanted signals coming from other radio equipment, possibly used in heavy earth moving machinery, operating in the vicinity. Is this a realstic approach to these problems, or simply a well intentioned but misdirected application?
Thanks to all who have responded.
Jim
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Old 07-27-2004, 11:12 AM
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Default RE: Ferrite bead filters...when and where????

ORIGINAL: Capt Jim

Apparently, from what little I hear locally, they are being employed in an attempt to reduce ignition interference from gasoline motors, and also to protect against unwanted signals coming from other radio equipment, possibly used in heavy earth moving machinery, operating in the vicinity. Is this a realstic approach to these problems, or simply a well intentioned but misdirected application?
Thanks to all who have responded.
Jim
Who knows? No one seems to want to run accurate tests.
The best way to protect from ignition noise is shielding at the source.
I don't see how they could protect from outside interference unless you put them on the antenna - and that sure would not be a wise thing to do.
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