[RFI] New Larger Fair-Rite #31 Toroid
dave at nk7z.net
Fri Apr 14 20:01:09 EDT 2017
Thank you Jim!
73s and thanks,
On 04/14/2017 11:33 AM, Jim Brown wrote:
> On Fri,4/14/2017 10:26 AM, Dave Cole wrote:
>> A question for you... Looking at the "Impedance vs. Frequency vs.
>> Turn count" graph at:
>> It looks like these new cores only have two or three K of impedance
>> with five turns... Am I interpreting this correctly?
>> If so, then using two of them with five turns becomes the standard if
>> I want more than five K impedance? Is that true?
> The number of turns (and to to the extent that it affects capacitance,
> wire size and spacing) sets the resonant frequency. The Fair-Rite data
> is most likely for small diameter wire. If you want the choke to be
> effective where 5 turns puts it, yes, two chokes in series would be the
> way to get there. A choke wound with RG8/11 size coax would have the
> same inductance but more capacitance between windings if those windings
> are closely spaced, so the resonance would be a bit lower.
> And, of course, more turns will lower the resonance even more, and
> because R also increases with N-squared, also raise the impedance.
> 73, Jim K9YC
>> 73s and thanks,
>> On 04/14/2017 09:53 AM, Jim Brown wrote:
>>> Yesterday, I got a quote on this part from Dexter, a vendor that has
>>> been competitive for past orders. They don't have stock, minimum order
>>> is a full box, which is 25 pieces, $15.18 each. 50 pieces is $14.27
>>> (-6%). 100 pieces is $13.57. Delivery was quoted as 14 weeks.
>>> 73, Jim K9YC
>> RFI mailing list
>> RFI at contesting.com
> RFI mailing list
> RFI at contesting.com
More information about the RFI