[Elecraft] K3 RTTY Audio Thru External DSP

[D Joyce]

GM Jim and Merry Christmas

Yes I'm using a pair of TimeWave units between the K3 line output and the 
microKeyer II primarily for dual channel RTTY operation.  Both of these 
units provide an adjustable dual channel passband which can be centered on 
the standard tone pair frequencies.

Specifically the Main Rx audio goes from the Tip on the K3 Line output to 
the Line input on a DSP-599ZX and then from the DSP-599ZX Line output to the 
audio cable labeled "line out" on the K3R cable going to the microKeyer II. 
I'm also running a cable from the DSP-599ZX  speaker output to a small 2" 
mini speaker to be able to separately  monitor the main channel audio.

Then for the subRx audio, I take the signal from the Ring on the K3 Line 
output to the Audio Input on the DSP-59+ and from from the DSP-59+ Line 
Output to the Tip on the audio connector on the microKeyer II labeled Sub 
Rx.

I had the TimeWave units and decided to hook them up this way to provide 
independent control of the two audio channels for dual RTTY operation.  I'm 
using MMTTY within DX4Win for the main channel and I open a separate 
instance of MMTTY for the subreceiver audio.  This setup works very well for 
RTTY DX'ng and has resulted in being able to spot stations very quickly and 
work the DX.

73,

Doug  VE3MV


----- Original Message ----- 
From: "Jim Harris" <jim.w0em at yahoo.com>
To: "Elecraft Email" <elecraft at mailman.qth.net>
Sent: Saturday, December 24, 2011 5:08 PM
Subject: [Elecraft] K3 RTTY Audio Thru External DSP


Hi to the group and Merry Christmas
Has anyone used an external DSP (noise reduction) between the output of the 
K3 and a computer sound card? What was your experience with it? Before 
telling me the K3 provides all the noise reduction needed, remember the NR 
is turned off in digital modes. I'm contemplating using a JPS NIR-12, 
Noise/Interference Reduction Unit.
If anyone has any experience with this setup how did you hook it up? Which 
output from the K3 did you use; headphone, speaker or lineout? Which output 
from the DSP; headphone, speaker or lineout? Did you use or find necessary 
to use an isolation transformer between the K3 and the DSP and the computer 
sound card?
My primary concern is to prevent ground loops. The NIR-12 schematic appears 
not to have any isolation on the outputs as does the K3 on the lineout.
I would appreciate any meaningful comments.
Take pride in the USA. 73



Jim, W0EM
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