EMRFD Message Archive 2595

Message Date From Subject
2595 2009-01-17 06:07:44 Kenneth Stringham %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20core%2
I don't recall feedthru capacitors of this size, mostly values in
the 100pF and 1000pF range are the values. Feedthru capacitors used to
prevent RF from escaping from a shielded area. Larger capacitors would
be placed on the outside of the enclosure using discreet components to
prevent any lower frequencies from affecting buss lines.

Ken - AE1X
2596 2009-01-17 06:22:31 Sam Morgan Re: %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20co
Kenneth Stringham wrote:
>
>
> I don't recall feedthru capacitors of this size, mostly values in
> the 100pF and 1000pF range are the values. Feedthru capacitors used to
> prevent RF from escaping from a shielded area. Larger capacitors would
> be placed on the outside of the enclosure using discreet components to
> prevent any lower frequencies from affecting buss lines.
>
Just above the 1st picture of his enclosure you will find this comment:
"Incoming +12V is fed through a 0.01uF feedthrough capacitor and a ferrite bead
(multi-aperture core)."

http://www.cliftonlaboratories.com/using_softrock_as_a_panadapter_for_the_k2.htm

I'm not saying that is what I must use, but being a clueless builder I tend to
try to do what ever "they" say do. I'm defiantly open to any counter proposals
as to what to use in that application, and where to find the components.

--
GB & 73
KA5OAI
Sam Morgan
Linux, the lifetime learning experience.
2597 2009-01-17 08:19:30 timshoppa Re: %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20co
2598 2009-01-17 12:16:41 Gary Johnson Re: %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20co
Two parts sources of interest here:

<http://www.cwsbytemark.com/> is a good supplier of ferrites in small quantities. I picked
up a bunch of binocular cores there that were otherwise a bit hard to find.

<http://www.emifiltercompany.com/> is a great source for new overstock feedthrus. Click
on the Bargains button and see what they have. The prices are very good. This is all stuff that
they manufacture, and it's all new. You may need to wade thru their online catalog to make
sense of the part numbers, but it's worthwhile. Quantities are "unknown" so when you try to
order, say, 10 and it says out of stock, try 8, then 6, etc. and eventually it will say they are
magically in stock!

And, indeed, it's usually fine to use a small feedthru, like 1 nF, to take care of the hard-to-
filter higher freqs, with a larger ceramic cap (with short leads) tacked on right where it goes
thru the box.

-Gary, WB9JPS
2601 2009-01-17 16:17:37 bobtbobbo Re: %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20co
2602 2009-01-17 19:45:34 Sudipta Ghose Re: %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20co
2604 2009-01-17 23:54:23 Russell Shaw Re: %20Re%3Afeed%20through%20caps%20and%20multi-hole%20aperture%20co
Sudipta Ghose wrote:
>