I find very efficient and often much cheaper than using ferrite beads a
choke made with a proper coaxial line, moreover the coax choke is linear and
predictable in behaviour and response. Resonating a coax choke is like to
have a trap that stops RF even when the impedance is high at the point.
It could be I've been quite unlucky but I found often ferrites that should
have been the same compound (and size) but in facts behaved different one to
another.
If this is almost neglectable in most uses where power it's not involved,
the chance of bad surprises is high when power limits of core current are
closely approached.
Ferrite not only can lose its characteristics irreversibly but can break and
has a tendency to follow a non linear behaviour when heat is developed.
This is not against the use of ferrite beads (or other forms) that may be a
good choice is several applications, but it's better to know where and when
not to use.
73,
Mauri I4JMY
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