🚀 go-pugleaf

Brian Carey 283-4181 (careyb@dallas.jsc.nasa.gov) wrote:
: 
: What is a ferite bead? The one talked about below.
: 
: The "Y" harness might be acting like an antenna and causing interference
: with the receiver.  I have had this problem and fixed it by running the base
: of the "Y" cable through a ferite bead (one turn) to choke off the RF. This
: worked with an airtronics receiver.  When I install servos in the wings of
: my gliders I go ahead and put the ferrite bead in every installation and
: have not had any problems since.
Ferrite is from the word Ferrous or iron based.      

A ferrite bead is a toroid (doughnut) made of this iron based
material. What the writer was talking about was to run the
control wire through the center of the toroid, wrap it back
around and through the center once again (one turn).

When currents flow through a wire they create electric and magnetic
fields around the wire. By passing the wire through the ferrite
bead, these fields cause currents to flow in the bead which is 
a lossy material for RF (Radio Frequency) energy. Therefore, if
you are receiving this RF energy into the wires to your servo,
the energy will be dissipated in the bead in the form of heat
before it can get back into your receiver circuitry and mess things
up there.