[Amps] Ferrite Core for 160M PI Output ?

[Jim Brown]

On Tue,6/13/2017 9:10 AM, JC wrote:
> PI network loss is related with the Q of the inductor, you need material #2
> or #6 ( better stability with temperature), #61 #77 are good for BALUN or
> chokes and not good for inductors with high Q.

#77 is very lossy, not good for inductors to handle power, or have high 
Q. #61 is low loss below about 10 MHz, but loss increases above that 
frequency. Again, study the Fair-Rite catalog and my tutorial. Here's 
the tech data sheet for #61.

http://www.fair-rite.com/61-material-data-sheet/

The first graph is a plot of mu' (classic mu) and mu'' (the loss 
component of impedance) vs frequency. Note that mu'' is off the graph 
low below 8 MHz, then rises rapidly so that it is quite lossy by 30 MHz.

Here's the data sheet for #77. Note that #77 is starting to get lossy at 
100 kHz, and is as lossy at 1 MHz as #61 is at 30 MHz.

http://www.fair-rite.com/77-material-data-sheet/

In general, a good common mode choke for noise suppression should be 
strongly resistive at the frequency of interest, ideally exhibiting a 
low Q resonance. #61 is useful as a core for common mode chokes above 
about 50 MHz.

73, Jim K9YC