Pete,
There may be other unknown factors in this. I discovered with my PC and
sound card a problem. I had a cable running from my modem to my sound
card internally in the PC. I disconnected it and the RFI went away.
Also, there's the cable that usually runs from the CD-Rom to the sound
card as well. You might want to try putting a ferrite on that too.
It may be the cable on the input but it may be something else connected
internally to the sound card.
Good luck!
73,
Jon
NA9D
-------------------------------------
Jon Ogden
Sales Engineer
Cain-Forlaw Company
847-202-9898 (Voice)
847-202-9896 (Fax)
jon.ogden@cain-forlaw.com
> -----Original Message-----
> From: Pete Smith [mailto:n4zr@contesting.com]
> Sent: Thursday, May 30, 2002 3:40 PM
> To: rfi@contesting.com
> Subject: [RFI] rfi to computer via sound card
>
>
> I'm setting up to record contests using an SB-16 sound card
> and Recall Pro
> software. At the moment I'm dealing with a severe RFI problem, which
> crashes the Recall software a few seconds into every
> transmission. I've
> determined that it is definitely coming in the [line in]
> cable from my
> radio's external AF output, because when I disconnect that
> line from the
> computer the program doesn't crash no matter how long I
> transmit. I've
> grounded the computer case and wound a number of turns of the
> [line in]
> cable around ferrite toroid cores, all without apparent
> benefit. Would it
> make sense to try .01 disc caps bypassing the conductors in
> the [line in]
> cable to the shield, in case this is differential mode
> interference rather
> than common mode, as I'd assumed?
>
> 73, Pete N4ZR
>
> Check out the World HF
> Contest Station Database at
> www.pvrc.org
>
>
>
>
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>
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