Measuring Ferrite Beads for RFI Suppression

This is a note that may be useful at some time – using the MFJ269 to measure ferrite bead value if you have some lying around of unknown quality.  MIX 43 beads are what we use for RF noise suppression.

Info from:  http://www.eham.net/articles/7596with MFJ269

  • Wind 5 turs #22 hookup wire through the bead undert test.
  • Set freq to 2 mHz
  • set meter for Reactance

A mix 43 bead inductance is about 500Ω.    Push button 3 times for reactance.  < 40 uh  it’s probably not mix 43 and may not work for noise suppression.  Higher reading — probably OK.  if  reactance is ~ 80 uh  may be  mix 77  better for 160 meters.

You may be able to get a check at higher freq than 2.5 mhz with fewer turns .

Other info

MIX 43 used for noise suppression  14-30 mhz
MIX 31 used below 14 mhz

~ by marksun on November 25, 2016.

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