[Elecraft] Toroid Balun Cores

[Jack Smith]

First, even a very thin gap may significantly reduce the core 
permeability. A high quality split core will have its mating surfaces 
lapped flat.

Second, if the core cracked because of excessive heat, it's likely the 
ferrite material incurred irreversible damage.

Jack K8ZOA


On 10/16/2011 5:58 PM, Jim Wiley wrote:
>
> OK, now I am confused (a normal state of affairs around here)
>
>
> If a "cracked" toroid core is useless,  then how do the "split bead"
> clamp-on cores manage to work?  Isn't the "split" equivalent to as great
> big lengthwise crack?
>
>
> I also seem to remember broken ring cores working again when glued
> together.
>
>
> After all, isn't a ferrite core itself manufactured from ferrite powder
> that has been "glued together" by a binding material?  Yes, the
> particles are pressed very close to one another,but they are still
> individual particles, are they not?
>
>
> - Jim, KL7CC
>
>
>
> John Ragle wrote:
>> <snip>
>>
>> I agree with the contributor(s) who said that the cracked toroid is
>> basically junk. It has lost its utility because the magnetic circuit is
>> broken at the crack. It is unlikely that superglue will restore it.
>>
>> John Ragle -- W1ZI
>>
>>
>>
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