On Sun,7/3/2016 10:05 AM, Steve Hunt wrote:
The #52 mix is readily available in size "240" toroids
I didn't find this part in the Fair-Rite catalog because the assigned
part number is for an inductive component, not for suppression. Many
ferrite materials are useful as inductive components at lower
frequencies and as suppression components at higher frequencies, so your
measurements are not surprising given the material specs (see p 11 in
the 17th edition of the Fair-Rite catalog).
BUT -- Fair-Rite controls specs based on their intended use, so
inductive components are controlled for inductance, but NOT for loss
impedance, and suppression components are controlled for suppression
impedance and not for inductance. For example -- you can buy a #43
2.4-in o.d. toroid controlled for impedance as Fair-Rite 2643803802. The
same size #43 toroid controlled for inductance is 5943003801.
This may seem picky to those who have not worked in component
manufacturing or as a circuit designer, but those of us who have
certainly understand the difference. Some components come off the
production line with relatively wide specs, and are sorted by measured
performance for one or more parameters. Those that meet one set of
performance tolerance specs get one part number, those that meet a
different set get a different one.
BTW -- it should be noted that Fair-Rite does sell some #61 parts with
suppression part numbers, but NOT the 2.4-in o.d. toroid. They made the
right call on that one -- #61 is not sufficiently lossy at HF to be
useful for suppression because the Q of the circuit resonance is too
high. They DO sell smaller #61 components for suppression. They ARE
lossy enough at high VHF and low UHF to be effective for use at those
frequencies. For example, a single 0461164181 clamp-on resonates around
450 MHz, and multiple turns through it would move the resonance down to
about 2M. 0461176451 resonates around 250 MHz, and two turns would move
it down to about 2M. In both cases, Z at resonance would increase by a
factor of 2-3.
73, Jim K9YC
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