[TVI-RFI-EMI] ferrite beads

Fri, 14 Jun 2002 19:00:35 -0400

Think as ALL cables exiting and entering any box as common mode RF antennas.
Treat them all as antennas.  Use the ferrites at both ends.

Be careful. The usual ferrite you find at flea markets are type 43 material
which do not do much below 30MHz.  You want type 73 material for HF.

73
Dennis Hennigan WA1HOG
ARRL NH TC
FN42as
Big Towers  Small Antennas
6,2,220,440,902,1296,
2304 and 10GHz
----- Original Message -----
From: "FireBrick" <[email protected]>
To: "tvi-rfi List" <[email protected]>
Sent: Friday, June 14, 2002 6:34 PM
Subject: [TVI-RFI-EMI] ferrite beads

> I'm building a patch cable from the sound card to the packet connector and
> fsk connector of my FT1000MP.
> On the packet connector there is audio in and out.
> On the FSK connector this is only audio out and FSK control.
>
> I'm using a high grade twisted, shielded cable.
> I have a bunch of tiny ferrite beads I bought long ago.
> Should I put the beads on both the audio in/out AND it's ground wires or
> just the audio in/out side of the circuit.
> The cable will have audio transformers at the rig end to minimize rf
> looping.
>
> I've got plenty of beads so that's not a problem.
> So should I put them at both ends of the cable?
>
> I don't have a big rfi problem but want to minimize the chance as much as
> possible.
>
>
> ------------------------------------------------------------
> When your over 50: You no longer think of speed limits as a challenge.
> ------------------------------------------------------------
>
> Bill H. in Chicagoland
> [email protected]
>
>
>
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