[Elecraft] KPA100 and KAT100 in EC2 - is replacement of L1 on AUX2 necessary?

[Don Wilhelm]

Brian,

If the toroid cores have a painted color on them, they are *not* ferrite 
cores.
The ferrite cores are a dull gray.  The more common ferrite cores are 
type 43 Mix, but could also be a 61 mix.  The 61 mix is a lighter shade 
of grey than the 43 mix.
For reference, the tiny cores used for winding the KSB2 RFC1 and RFC2 
are FT25-43.
The FT designates a ferrite material,
The "25" or "37" (or any other number) is the outer diameter in inches x 
100 - i.e .25 inch diameter is 25.
The number after the dash is the ferrite mixture type.

I hope that helps.

73,
Don W3FPR

On 3/26/2015 11:15 PM, Brian Denley wrote:
> Ken and Don:
> I am interested in this as well.  My KAT100 is complete in the EC-2 and I just started the KPA100 build today.  I'm sure I have a few spare toroid cores around here.  How do I tell if they are the ones specified by Don?
>
> Brian
> KB1VBF
> Sent from my iPad
>
>> On Mar 26, 2015, at 7:57 AM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>>
>> Ken,
>>
>> Although *supposedly* the inductor should be able to supply the needed current, I recommend replacing it with a toroid.
>> Especially if the inductor is of the older miniature type.
>> 12 turns on a FT25-43 or FT37-43 core will work nicely.
>>