[TowerTalk] Fair rite materials for choke baluns

[Steve Hunt]

Note what I said about duty cycles!

Steve G3TXQ


On 06/07/2016 00:00, Richard (Rick) Karlquist wrote:
> On 7/5/2016 11:00 AM, Steve Hunt wrote:
>> Do the maths on saturation - you'll find that core overheating occurs
>> well before saturation for the duty-cycles typical of Ham operation.
>>
>> To quote Amidon: "Overheating of the core will usually take place long
>> before saturation in most applications above 100kHz."
>>
>> Steve G3TXQ
>
> This generalization is valid for cores with an air gap and
> powdered iron cores (which essentially have a built in air gap).
> It most definitely doesn't apply to closed gap ferrites,
> such as toroids.  One dit can not only saturate them, but
> actually magnetize them.  I have actually done this, accidentally,
> when I tried to use a current transformer and the secondary
> was unloaded.  It was something of a corner case since the
> primary of a current transformer is only 1 "turn".
>
> Rick N6RK
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