Re: 80 meter bpf toroid winding 30 turns givel 4.3 micro Henrys, not 3.8


Arv Evans
 

As mentioned earlier by someone else,  compressing or spreading 
the turns on a toroid core probably does not change the inductance
very much (the number of turns remains the same).  What it does 
do is to change the distributed capacitance between turns.  

Also mentioned by others is that the apparent inductance of metallic 
cores does change with frequency.  This could be a factor if you are 
operating the core at widely different frequencies.

DC loading also causes toroidal cores to change apparent 
inductance.  While probably not an issue with DC isolated 
filters, it could be problematic for tank circuits that carry DC
current.

Arv
_._



On Mon, Sep 7, 2020 at 8:56 AM Kees T <windy10605@...> wrote:
KI7MWA,

If xx turns of #28 wire do not allow moving the turns around a little, try #30 wire.

73 Kees K5BCQ

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