Re the Fair-Rite 2631814002, Arrow sells these in single unit quantities at
$17.68 and has three in stock...maybe not for long! Shipping is also free...a
new practice for Arrow. Arrow's prices have generally been considerable lower
on Fair-Rite products than the other vendors I've searched, and if you
register, you get a bit of a price break..
Mouser is showing 251 in stock with a single unit price of $18.09.
---
Chuck, AE4CW
-----Original Message-----
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Contents of RFI digest..."
Today's Topics:
1. Re: New Larger Fair-Rite #31 Toroid (Jim Brown)
2. Re: New Larger Fair-Rite #31 Toroid (Dave Cole)
3. Re: New Larger Fair-Rite #31 Toroid (Jim Brown)
4. Re: New Larger Fair-Rite #31 Toroid (Chuck Gooden)
5. Re: New Larger Fair-Rite #31 Toroid (Jim Brown)
6. Re: New Larger Fair-Rite #31 Toroid (Dave Cole)
----------------------------------------------------------------------
Message: 1
Date: Fri, 14 Apr 2017 09:53:09 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: rfi@contesting.com, towertalk reflector <towertalk@contesting.com>
Subject: Re: [RFI] New Larger Fair-Rite #31 Toroid
Message-ID:
<ce55463f-e551-b656-9a4b-5ba271c8ec7a@audiosystemsgroup.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
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
On Sun,3/26/2017 4:22 PM, Jim Brown wrote:
> KY8D asked me about a new, larger #31 toroid that has recently been
> added to the catalog. It's 4-in o.d., 3-in i.d, and 1-inch long.
>
> http://www.fair-rite.com/product/round-cable-emi-suppression-cores-263
> 1814002/
>
>
> Note the impedance data for 1, 3, and 5 turns at the bottom of the page.
>
> Gan's email arrived today (Sunday) so I haven't had the opportunity
> yet to investigate pricing. My guess is at least double the cost of
> the 2.4-in toroid, but because it's twice the length (1-in as opposed
> to 0.5-in for the 2.4-in toroid), a single core will likely be
> equivalent to two of the 2.4-in cores, so fewer cores will be required
> to achieve the same choking Z. More important, the much larger i.d.
> will allow more turns and/or larger coax.
>
> 73, Jim K9YC
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
------------------------------
Message: 2
Date: Fri, 14 Apr 2017 10:26:19 -0700
From: Dave Cole <dave@nk7z.net>
To: rfi@contesting.com
Subject: Re: [RFI] New Larger Fair-Rite #31 Toroid
Message-ID: <978afca3-90d0-2cb5-634b-90bab01defea@nk7z.net>
Content-Type: text/plain; charset=windows-1252; format=flowed
Jim,
A question for you... Looking at the "Impedance vs. Frequency vs. Turn count"
graph at:
http://www.fair-rite.com/product/round-cable-emi-suppression-cores-2631814002/
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?
73s and thanks,
Dave
NK7Z
http://www.nk7z.net
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
------------------------------
Message: 3
Date: Fri, 14 Apr 2017 11:33:13 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: rfi@contesting.com
Subject: Re: [RFI] New Larger Fair-Rite #31 Toroid
Message-ID:
<9658385d-a2f1-2df6-5e49-52bd6de6a0d1@audiosystemsgroup.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
On Fri,4/14/2017 10:26 AM, Dave Cole wrote:
> Jim,
>
> A question for you... Looking at the "Impedance vs. Frequency vs.
> Turn count" graph at:
>
> http://www.fair-rite.com/product/round-cable-emi-suppression-cores-263
> 1814002/
>
>
> It looks like these new cores only have two or three K of impedance
> with five turns... Am I interpreting this correctly?
Yes.
>
> 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,
> Dave
> NK7Z
> http://www.nk7z.net
>
> 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@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
------------------------------
Message: 4
Date: Fri, 14 Apr 2017 14:27:01 -0500
From: Chuck Gooden <Chuck.Gooden@comcast.net>
To: rfi@contesting.com
Subject: Re: [RFI] New Larger Fair-Rite #31 Toroid
Message-ID: <e2486898-80d8-8d11-6623-59cc46ca35e9@comcast.net>
Content-Type: text/plain; charset=windows-1252; format=flowed
Jim,
Could you clarify if you mean 5 turns through each core as in separate chokes
in series. Or 5 turns through both cores as in 1 choke with two cores? Or is
there a difference? It doesn't seem like there would be a difference.
Chuck K9LC
On 4/14/2017 1:33 PM, Jim Brown wrote:
> 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.
------------------------------
Message: 5
Date: Fri, 14 Apr 2017 13:39:29 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: rfi@contesting.com
Subject: Re: [RFI] New Larger Fair-Rite #31 Toroid
Message-ID:
<66d585ea-9fab-f175-57dd-33716e46e034@audiosystemsgroup.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
I mean two chokes, each with five turns, wound on the same coax. There is a
HUGE difference. Study k9yc.com/RFI-Ham.pdf, which includes a tutorial on how
ferrite chokes work.
The chokes in series keep the same resonant frequency (and the broad resonant
peak is the range where they work as chokes). Winding only one choke on two
cores lowers the resonant frequency by the square root of 2, because there's
twice as much L. and Fr varies as the square root of LC).
73, Jim K9YC
On Fri,4/14/2017 12:27 PM, Chuck Gooden wrote:
> Jim,
>
> Could you clarify if you mean 5 turns through each core as in separate
> chokes in series. Or 5 turns through both cores as in 1 choke with
> two cores? Or is there a difference? It doesn't seem like there would
> be a difference.
>
> Chuck K9LC
>
>
> On 4/14/2017 1:33 PM, Jim Brown wrote:
>> 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.
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
------------------------------
Message: 6
Date: Fri, 14 Apr 2017 17:01:09 -0700
From: Dave Cole <dave@nk7z.net>
To: rfi@contesting.com
Subject: Re: [RFI] New Larger Fair-Rite #31 Toroid
Message-ID: <9d76bfb4-505c-fc9e-70b5-6ea643934e2a@nk7z.net>
Content-Type: text/plain; charset=windows-1252; format=flowed
Thank you Jim!
73s and thanks,
Dave
NK7Z
http://www.nk7z.net
On 04/14/2017 11:33 AM, Jim Brown wrote:
> On Fri,4/14/2017 10:26 AM, Dave Cole wrote:
>> Jim,
>>
>> A question for you... Looking at the "Impedance vs. Frequency vs.
>> Turn count" graph at:
>>
>> http://www.fair-rite.com/product/round-cable-emi-suppression-cores-26
>> 31814002/
>>
>>
>> It looks like these new cores only have two or three K of impedance
>> with five turns... Am I interpreting this correctly?
>
> Yes.
>
>>
>> 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,
>> Dave
>> NK7Z
>> http://www.nk7z.net
>>
>> 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@contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>>
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
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