K3 and data modes

[Ken Chandler]

Hi group
Question
Knowing that the k3 will tx data psk, afsk etc, I'm a bit puzzled and  
I know someone here knows the answer, but my apologies if this has  
already been covered.
Working. PSK es AFSK data modes I have always used isolation  
transformers between the radio es computer to prevent ground loops etc.
If I direct wire line in, line out to the K3 &  computer what is there  
to prevent RFI ground loops etc.
Previously, I have used Isoterm devices from Johnny Melvin, G3LIV
Which are very good.
So do I need a seperate device between the k3 and computer or am I  
barking up the wrong tree es the k3 as a stand alone unit will do all  
that I want to do!!!!

Ken..G0ORH

Sent from my iPhone



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[Don Wilhelm-4]

Ken,

The K3 has internal isolation transformers, no need for any external box
- like they say in the ad for pasta sauce "It's already in there".

73,
Don W3FPR

Ken Chandler wrote:

> Hi group
> Question
> Knowing that the k3 will tx data psk, afsk etc, I'm a bit puzzled and  
> I know someone here knows the answer, but my apologies if this has  
> already been covered.
> Working. PSK es AFSK data modes I have always used isolation  
> transformers between the radio es computer to prevent ground loops etc.
> If I direct wire line in, line out to the K3 &  computer what is there  
> to prevent RFI ground loops etc.
> Previously, I have used Isoterm devices from Johnny Melvin, G3LIV
> Which are very good.
> So do I need a seperate device between the k3 and computer or am I  
> barking up the wrong tree es the k3 as a stand alone unit will do all  
> that I want to do!!!!
>
> Ken..G0ORH
>
> Sent from my iPhone
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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[Jim Brown-10]

On Mon, 28 Dec 2009 16:20:44 +0000, Ken Chandler wrote:

>Working. PSK es AFSK data modes I have always used isolation  
>transformers between the radio es computer to prevent ground loops
etc.
>If I direct wire line in, line out to the K3 &  computer what is there  
>to prevent RFI ground loops etc.

TOTALLY UN-NECESSARY!  As others have noted, the K3 works VERY WELL in
data modes with nothing more than properly wired 1/8-inch cables
between LIN OUT and a computer sound card, and between LIN IN and the
sound card, PLUS simple (and quite proper) BONDING between the chassis
of the computer and the chassis of the K3. See

http://audiosystemsgroup.com/HamInterfacing.pdf  (Power Point slides)

and the Appendix on audio in

http://audiosystemsgroup.com/RFI-Ham.pdf   (a tutorial that goes with
it)

I do LOTS of RTTY contesting, as well as some PSK31. For RTTY, I use
MMTTY, along with N1MM Logger if it's a contest. For PSK31, I use DM780
and HRD. I use VOX rather than PTT.

Note also that RTTY and PSK31 decoding software will refuse to decode
the combined output of the two receivers in Diversity mode, thanks to
small time offsets between signals from the two RXs. These offsets are
both within the K3 DSP system and the RF path to different RX antennas.

73,

Jim Brown K9YC


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