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Author Topic: Source for filament choke core  (Read 255 times)

K0IZ

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Source for filament choke core
« on: May 03, 2021, 08:40:19 AM »

I'm building a (2) 813 amp for 20M, so need a filament choke.  I was going to order the Amidon FLC-10 kit ($15) but minimum order is $20 and shipping is $18 cheapest way.  Total of $38!  Surely there must be a less expensive source for a 1/2"x4" type 61 or 33 ferrite rod?  I have plenty of wire so don't need a kit.  Carl (KM1H), any ideas?

John.
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K6AER

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Re: Source for filament choke core
« Reply #1 on: May 03, 2021, 09:46:17 AM »

You can find the rods at Newark for $.30 each:

https://www.newark.com/ferroxcube/rod6-20-3c90/ferrite-rod-20x6mm/dp/63R5830?mckv=sDuqIrTkQ_dc|pcrid||plid||kword||match|e|slid||product|63R5830|pgrid|1232552745342183|ptaid|pla-4580634170239482|&msclkid=b8c3b92e89291abb27fbd9bea17a8f7b&CMP=KNC-BUSA-GEN-Shopping-NewStructure-Passive-Components


Mike - K6AER
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WB6BYU

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Re: Source for filament choke core
« Reply #2 on: May 03, 2021, 11:05:37 AM »

That one from Newark is only 1/4" diameter (6mm), rather than 1/2".
But you probably could use several wrapped together with tape.

ZL1PB

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Re: Source for filament choke core
« Reply #3 on: May 03, 2021, 11:23:04 AM »

Why not use a toroid and wind your own.
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K1KIM

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Re: Source for filament choke core
« Reply #4 on: May 03, 2021, 02:44:03 PM »

Did you check Mouser?
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K0IZ

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Re: Source for filament choke core
« Reply #5 on: May 03, 2021, 03:36:30 PM »

Mike - that's pretty short for a plate choke (20mm)!  I also searched Mouser and didn't find any at all.  I considered winding a toroid, and still might.  Seemed isolation between ends would be better with a rod (and wire ends 4" apart), but if I only used 1/2 or so of toroid, might be ok.
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KM1H

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Re: Source for filament choke core
« Reply #6 on: May 03, 2021, 05:07:23 PM »

Quote
I'm building a (2) 813 amp for 20M, so need a filament choke.  I was going to order the Amidon FLC-10 kit ($15) but minimum order is $20 and shipping is $18 cheapest way.  Total of $38!  Surely there must be a less expensive source for a 1/2"x4" type 61 or 33 ferrite rod?  I have plenty of wire so don't need a kit.  Carl (KM1H), any ideas?

John, I have 1/2"x 4" type 61 or 33 ferrite rods plus the 7.5" versions of both. $20 and $30 shipped respectively, ferrite aint light!

Carl

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K0IZ

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Re: Source for filament choke core
« Reply #7 on: May 03, 2021, 06:26:13 PM »

Carl, thank you!  4" type 61 would be super.  I didn't see your email address so let me know, I'm ok on qrz
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KM1H

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Re: Source for filament choke core
« Reply #8 on: May 04, 2021, 01:11:59 PM »

Check your eham messages
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