Thanks, Dave. Your site is very informative. I really like it.
However, what I need are some of those small ferrite beads that fit over a
single strand of
"hookup" wire, usually installed just at where the wire connects to, say, a
tube socket pin.
I am not looking for the larger ones as I have bought a kit of the snap-on
types from Palomar
some time ago.
I can find mix 43 and mix 71 beads, but so far, no mix 31. I even tried eBay.
In my TV-2/U there are no beads on any leads in that model. They were added to
almost
every lead in following models, although I don't know what "mix" they used. I
have a (so far)
non-working TV-2/BU here which is loaded with those.
In any case, when testing, for instance, voltage regulator tubes in the TV-2/U,
the tube ends
up oscillating something fierce. Enough so that if I let it go on too long, it
burns out the 83
rectifier tube!
I am trying this forum rather than any other since I know that the members here
use ferrite
chokes a lot. If I know of a forum more attuned to my particular issue, I would
move my
questions there.
Thanks for the info. It really helps me help other hams with their RFI problems.
Ken W7EKB
On 17 Jul 2024 at 12:16, Dave (NK7Z) wrote:
> Hi,
>
> Take a look at:
>
> https://www.nk7z.net/rfi-now-house-cleaning/
>
> that is a little piece I put together dealing with cleaning up RFI on
> various items... About halfway down is a list of ferrites by type,
> with Fair-Rite part numbers. Cut those numbers and paste them into
> the catalogs of the various parts houses...
>
> Here is the Mouser link:
>
> https://www.mouser.com/ProductDetail/Fair-Rite/2631803802?qs=P8bU7i9nN
> AWMk1EJQzshLg%3D%3D
>
> and here is the Fair-Rite link:
>
> https://fair-rite.com/product/round-cable-emi-suppression-cores-263180
> 3802/
>
> If you are trying to suppress 14 MHz and lower I would use mix31, if
> above 14, mix43.
>
> Place about 7 to 10 wraps of cable on a ferrite. Each pass through
> center counts as a turn...
>
> Normally in the Fair-Rite part number the second pair of number is the
> mix number...
>
> Hope this helps...
>
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist, RFI
> ARRL Asst. Director, NW Division, Technical Resources
>
> On 7/17/24 09:45, Ken Gordon wrote:
> > I am in the process of building and/or serviceing a few devices here
> > which I believe could use ferrite beads on some of the leads.
> >
> > One of those "devices" is a TV-2/U tube tester, an early model which
> > does not have the beads on certain leads and thus oscillates when
> > testing certain tubes.
> >
> > I am also working on a couple of HF wattmeters.
> >
> > I would like advice from knowledgeable members of this group was to
> > what "mix" of ferrite would be most suitable.
> >
> > From my cursory investitagation, it would appear that mix 31 would
> > be the mix I would need,
> > at least for the HF wattmeter project, but also that would appear to
> > be useful for my tube tester issues.
> >
> > Yet checking Mouser and eBay for those beads, all I find are mix 43
> > and mix 73, and, so far, no mix 31.
> >
> > I have downloaded the necessary documenation from Palomar's site
> > listning the various characteristices for the various mixes, and it
> > still seems to me that mix 31 would be my best choice.
> >
> > Anyone?
> >
> > Ken W7EKB
> >
> > _______________________________________________
> > RFI mailing list
> > RFI@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
>
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