Marty,
Thanks a lot for the advice I had tried twice and had both of them wired
wrong, it works FB, I'll have to test with the amp and a kilowatt tomorrow
night! Maybe 3Y0C will be on RTTY then...
George / KF9YR
P.S. thanks for the opto's, they arrived this last weekend. Don't sweat the
nitpickers, I wouldn't have minded paying extra for you to make a little
profit for your time!
Now if someone would buy all the parts for the W5XD keyers and put them in
a bag....
-----Original Message-----
From: Marty Tippin [mailto:ki0lo@yahoo.com]
Sent: Monday, February 05, 2001 11:00 PM
To: George Skoubis
Subject: Re: [WriteLog] RFI and Audio Isolation Transformers
Red and yellow are the input side, black and white are
the output side. You put the transformer in series
somewhere in the line - not in parallel with anything
Wire yellow to center conductor, red to ground. Do
the same for white and black (keep the ground on red
and black separate, of course). You now have an
isolation transformer between the two things you
wanted to isolate. There is no DC continuity between
the two sides.
No more hum.
73,
-Marty NW0L
martyt@pobox.com
--- George Skoubis <gaskoub@mhtc.net> wrote:
>
> Hi Everyone,
> I have a dumb question...
> I have an RFI problem on 20 meters when I connect
> my soundcard to the
> audio in and audio out jacks on my Omni VI +. I
> have grounded both the
> computer case and the transceiver with short direct
> ground wires to the
> common ground point (8 inch strap for the computer,
> 24 inch for the
> transceiver).
> If I unplug the phone plugs from the back of the
> rig the RFI hum goes
> away, when I plug them back in the noise is back.
> I bought a couple of audio isolation transformers
> from RS (273-1374) but I
> can't get them to pass the audio signals. I
> soldered the White wire to the
> center conductor on jack #1 then the Black wire to
> the jack #2 center
> conductor. I then soldered the Yellow wire to the
> ground tab on jack #1 and
> the Red wire to ground on jack #2.
> I used a non-conductive box since I didn't want
> the audio grounds from
> input and output to mix (I figured this would defeat
> the isolation part).
> No audio passes through when soldered this way and
> there is only
> continuity between center conductors when measured
> with a VOM. I have three
> of these "isolators" and so far all they're good for
> is isolating the audio
> signals from between the rig and the sound card.
> Can one of you tell me what obvious, dumb, "I
> should have remembered
> that!", mistake I'm making?????
> I want to get on for the contest part-time this
> weekend (I'm on-call this
> weekend so it will really be part-time) and I
> haven't ordered the new
> motherboard so I can do FSK (Longer Story, don't buy
> a FIC Athlon
> motherboard!!!!!) so a fast answer would be
> appreciated.
>
> Thanks everyone,
>
> George / KF9YR
>
>
> --
> WWW: http://www.writelog.com/
> Submissions: writelog@contesting.com
> Administrative requests:
> writelog-REQUEST@contesting.com
> Problems:
> owner-writelog@contesting.com
>
>
=====
-Marty NW0L (ex KI0LO)
martyt@pobox.com
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