[TowerTalk] Ferrite material Laird 28

[Richard (Rick) Karlquist]

On 3/27/2017 4:36 PM, Jim Brown wrote:
> On Mon,3/27/2017 2:12 PM, Richard (Rick) Karlquist wrote:
>> What I meant by lossier is that in a common mode
>> choke, there would be more heat dissipation loss
>> with the Laird.  I did NOT mean that the series
>> resistance was higher.
>
> Not necessarily. Remember that power is I squared R, and if R is
> sufficiently large, I falls to the point that power is small (because
> it's falling twice as fast as R increases). OTOH, that R is undesired
> when using the core in a real transformer (that is, the core carries all
> of the flux for the differential power). I know you know this, Rick, but
> this is for others on the reflector who may not.
>
> 73, Jim K9YC
>>

The confusion of the Z = R + jX model as you described is why I
measure ferrites using the Y = G + jB model.  Some network analyzers
can display directly in this format.  In this case, G describes
the losses in a common mode choke, and 1/G is a figure
of merit.  The G value I measured on Fair-Rite #43 was smaller than the 
G value on competitors versions.  Hope this clears up the
confusion.

73
Rick N6RK