[RFI] Dell D505 PA-10 PS

Kimo Chun kimo at lava.net
Fri Aug 10 13:09:29 PDT 2012



Use a type 43 or 44 ferrite core. Though we often call them "toroids" it may
be categorized in the catalog as an EMI/RFI suppressor. Wind as many turns
through it as you can. If the connectors won't fit then get split cores of
the same type with an appropriate inside diameter to clear the wire bundle
and use several of them (more the better) as they will be less effective
than the multiple turns through a core. IF you have any HF problems,
especially low HF frequencies, and the 43 doesn't clear that up you can try
adding cores of type 31. They will combine their effective ranges. There is
overlap in their ranges with 43/44 being more effective at the higher end.
They don't have to be "snug" on the cable.


I just looked at the Fair-rite Web site. I didn't know they came out with
larger cores "3" ID. They used to be max. 1.5" ID good for 5 or 6 turns of
RG-213 through them. Cable-tie or tape them in place. They are brittle.
Order extras.


You can order small quantities from Mouser or other sources. Examples There
are other sizes.


Fair-rite 2643814002        Type 43 round cable solid core.  3 in nominal
ID. 25-300 MHz

Fair-rite 2631814002        Type 31 round cable solid core.  3 in nominal
ID. 1-300 MHz

Fair-rite 0431177081        Type 31 split core "round cable snap-its". 1 in
nominal ID.  1-300 MHz

Fair-rite 0444177081        Type 44 split core "round cable snap-its". 1 in
nominal ID.  25-300 MHz


Good luck.


Kimo  KH7U



Message: 1

Date: Fri, 10 Aug 2012 12:57:00 -0600

From: Patrick Dyer <pjdyer at swbell.net>

Subject: [RFI] Dell D505 PA-10 PS

To: "rfi at contesting.com" <rfi at contesting.com>

Message-ID: <5025597C.1020707 at swbell.net>

Content-Type: text/plain; charset=ISO-8859-1; format=flowed


I just got a refurbished Dell D505 with XP Pro to handle some of my legacy
programs that wont run on this 64-bit Win7 OS.  The PA-10 PS with it puts
out a lot of trash 50-150 MHz (and probably elsewhere).


What ferrites (material, size) and number of turns thru would be the best
bet on its cords to reduce/eliminate that RFI ?


73, Pat - WA5IYX





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