[Elecraft] my KPA1500 and 160M

Thu Sep 3 01:58:48 EDT 2020

That reference contradicts itself by its ceramic refence point to ;

A *ceramic* is any of the various hard, brittle, heat-resistant and 
corrosion-resistant materials made by shaping and then firing a 
nonmetallic^[1] <https://en.wikipedia.org/wiki/Ceramic#cite_note-1> 
mineral, such as clay, at a high temperature.^[2] 
<https://en.wikipedia.org/wiki/Ceramic#cite_note-2> Common examples are 
earthenware <https://en.wikipedia.org/wiki/Earthenware>, porcelain 
<https://en.wikipedia.org/wiki/Porcelain>, and brick 
<https://en.wikipedia.org/wiki/Brick>.

Ferrite is not a non-metallic material. I would advise the wiki to 
correct it's mistake. The facts are given

by those expert on the subject that the dielectric molecular alignment 
method of heating does not apply to ferrite core heat loss,

since the ferrite core being a high permeability material, already has 
its molecules aligned, and therefore no realignment, with its heat

generating resistance being heat produced by the dielectric method is 
happening.

You have not referred to any reference stating a ferrite core is a 
dielectric.

POWER CONSIDERATIONS
(Iron Powder & Ferrite)

How large a core is needed to handle a certain amount of power? This is 
a question often asked, but unfortunately there is no simple answer.

There are several factors involved such as: cross sectional area of the 
core, core material, turns count, and of course the variables of applied 
voltage and operating frequency.

Overheating of the coil will usually take place long before saturation 
in most applications above 100 KHz. Now the question becomes "How large 
a core must I have to prevent overheating at a given frequency and power 
level? "

Overheating can be caused by both wire and core material losses. Wire 
heating is affected by both DC and AC currents, while core heating is 
affected only by the AC (induced eddy *currents*) content of the signal. 
With a normal sine wave signal above 100 KHz, both the Iron Powder and 
Ferrite type cores will first be affected by overheating caused by core 
losses, rather than by saturation.

Nothing about dielectric heating here.

Mr Lazy

On 3/9/20 3:31 pm, David Gilbert wrote:
>
>
> If you weren't so stubborn (or lazy) you could have easily found this 
> reference on Wikipedia:
>
> "A *ferrite* is a ceramic material made by mixing and firing large 
> proportions of iron(III) oxide (Fe_2 O_3 , rust) blended with small 
> proportions of one or more additional metallic elements, such as 
> barium, manganese, nickel, and zinc."
>
> https://en.wikipedia.org/wiki/Ferrite_(magnet)
>
> Note the term "*ceramic*".  In what world do you live where ceramics 
> don't have dielectric properties?  Ever heard of ceramic capacitors?
>
> A simple Google search for "dielectric properties of ferrites" (of 
> which of course there are many varieties) turns up this sampling of 
> references out of a total of approximately *1,230,000* hits:
>
> https://ieeexplore.ieee.org/abstract/document/4051871
>
> https://www.sciencedirect.com/science/article/abs/pii/S0925838809002084
>
> https://pdfs.semanticscholar.org/9298/4f47d7c6060357c3f8c39bc142911960c5cf.pdf 
> (scroll down to page 58)
>
> https://aip.scitation.org/doi/abs/10.1063/1.4792494?journalCode=jap
>
> http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.416.6977&rep=rep1&type=pdf
>
> https://iopscience.iop.org/article/10.1143/JJAP.10.1520/meta
>
> https://ieeexplore.ieee.org/document/4051871
>
> https://www.hindawi.com/journals/jnp/2016/4709687/
>
> http://www.bjp-bg.com/papers/bjp2018_1_044-053.pdf
>
> http://www.ijera.com/papers/Vol7_issue2/Part-5/I0702054348.pdf
>
> http://chalcogen.ro/265_Farid.pdf
>
> Every one of those links talks about the dielectric properties of 
> ferrites.
>
> Dave   AB7E
>
>
>
> On 9/2/2020 9:47 PM, Adrian wrote:
>>
>> Please quote your online reference please regarding ferrite cores 
>> being a dielectric
>>
>> If so then my not just use un-enammeled wire on a course wound core ? 
>> A dielectric is an insulator ;
>>
>>
>>   Dielectric
>>
>> From Wikipedia, the free encyclopedia
>> Jump to navigation 
>> <https://en.wikipedia.org/wiki/Dielectric#mw-head>Jump to search 
>> <https://en.wikipedia.org/wiki/Dielectric#searchInput>
>> Not to be confused withDielectric constant 
>> <https://en.wikipedia.org/wiki/Dielectric_constant>orDialectic 
>> <https://en.wikipedia.org/wiki/Dialectic>.
>>
>>
>> A*dielectric*(or*dielectric material*) is anelectrical insulator 
>> <https://en.wikipedia.org/wiki/Insulator_(electricity)>
>>
>> I don't see any reference to ferrite cores being a dielectric online.
>>
>> The molecular alignment heating method regarding dielectric loss, is 
>> not mentioned on any ferrite core RF heating science, that I can find.
>>
>> Please read ;
>>
>> Predicting Temperature Rise of Ferrite Cored Transformers George 
>> Orenchak TSC Ferrite International 39105 North Magnetics Boulevard 
>> Wadsworth, IL 60083
>>
>>
>> "Core Losses Core losses are a significant contributor to the 
>> temperature rise of a transformer. Hysteresis loss, eddy *current* 
>> loss and residual loss all contribute to the total core loss. At high 
>> flux densities and relatively low frequencies, hysteresis losses are 
>> usually dominant. Hysteresis loss is the amount the magnetization of 
>> the ferrite material lags the magnetizing force because of molecular 
>> friction. The loss of energy due to hysteresis loss is proportional 
>> to the area of the static or low frequency B-H loop. At high 
>> frequencies, eddy current losses usually dominate. Eddy *current* 
>> loss is from a varying induction that produces electromotive forces, 
>> which cause a current to circulate within a magnetic material. These 
>> eddy *currents* result in energy loss. Understanding the behaviour of 
>> the combined total core loss as functions of flux density and of 
>> frequency is most important. "
>>
>>
>> Dielectric is not mentioned.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On 3/9/20 2:15 pm, David Gilbert wrote:
>>>
>>> If you weren't too stubborn you could find many, many online 
>>> references to the dielectric characteristics of ferrites.  A ferite 
>>> core absolutely IS a dielectric.  There is nothing false about what 
>>> I've been telling you.
>>>
>>> Dave  AB7E
>>>
>>>
>