[amsat-bb] Re: Ferrite RFI filters and Traps?

[Joe Fitzgerald]

> I cut the RFI Ferrite blobs off of all trash Keyboards and stuff.  These
> are great Ferrite devices.
>
>
>
> But what are they best for?

Bob,

Check out this article from Chuck Councilman W1HIS:

http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf

He wrote it from the perspective of an HF operator, but there is a lot of
useful information in it.

Chuck is fairly generous with his time, contact me off list if you want
his e-mail address.

In my personal experience, equipment vendors are mostly required to test
at >30MHz, so it would not surprise me if the pieces you pull off
discarded equipment are well suited to VHF/UHF.  Since the article was
written, ferrite has become easier to obtain in small quantities.  Mouser
has worked for me - it might be easiest to buy exactly what you need
rather than experiment with with whatever the junk box provides.

But sorting through junk boxes is fun too!

-Joe KM1P