Are seller's claims based on QRP testing to be trusted over the
ferrite manufacturer's specs?
On Mar 7, 2006, at 9:26 AM, Will Matney wrote:
>> From Palomars website;
>
> 61 mix
> u = 125
> For RFI: 1-1000 MHz
> For Coils: .2 to 10 MHz
> For Xfmrs: .2 to 100 MHz
>
> Is the only one that covers the full range from 160 to 6 meters or
> 2-30 MHz for that matter. Amidon and Fair-Rite say the same thing in
> some of their literature.
>
> http://www.palomar-engineers.com/Ferrite_Cores/ferrite_cores.html
>
> *********** REPLY SEPARATOR ***********
>
> On 3/7/06 at 8:56 AM R; Measures wrote:
>
>> On Mar 7, 2006, at 8:16 AM, Will Matney wrote:
>>
>>> Dan,
>>>
>>> For 2-30 MHz, the guy a Palomar Engineers said to use 61 in place of
>>> 43.
>>
>> On an oscilloscope, using 100w of RF, I observed that mix #61 begins
>> to
>> distort the waveform at c. 13MHz. Those who don't desire to generate
>> harmonics should probably follow the manufacturer's specs and not
>> operate 61 above 10MHz.
>>
>>> Their literature says to look at the frequency spec of each
>>> transformer (which is for narrow band types), and for broadband
>>> types,
>>> the upper frequency can be multiplied by X10 if I recall. The lower
>>> frequency though needs to be kept was the way I read it. Palomar buys
>>> direct from Amidon also. In designing the transformers, an inductive
>>> reactance of at least 200 ohms should be met, and make sure the flux
>>> density is below the knee on it's BH curve which is the linear
>>> region.
>>> Maximum Permeability is reached just above the start of the knee on
>>> the curve from the bottom.
>>>
>>> Best,
>>>
>>> Will
>>>
>>> *********** REPLY SEPARATOR ***********
>>>
>>> On 3/7/06 at 7:24 AM Dan Sawyer wrote:
>>>
>>>> I have to say I am very confused reading Amidon ferrite core specs.
>>>>
>>>> http://www.amidoncorp.com/aai_ferritecores.htm
>>>>
>>>> As an example in the paragraph description material 61 and 67 cores
>>>> are
>>>> good for transformers up to 200 MHz while in the spec sheet the
>>>> transformer claim is 500 MHz and 1000 MHz respectively.
>>>>
>>>> I am interested in building a solid state 1200 watt power amp for
>>>> 160
>>>> through 6 meters. What are the materials suitable for the input and
>>>> output transformers in that range?
>>>>
>>>> Thanks - Dan - kb0qil
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>>>
>>>
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>>>
>>
>>
>>
>> Rich Measures, 805.386.3734, AG6K, www.somis.org
>
>
>
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>
Rich Measures, 805.386.3734, AG6K, www.somis.org
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