K3 RTTY Audio Thru External DSP

[radioshoppe]

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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[Don Wilhelm-4]

Jim,

As I recall, there is a reason NR is not available in digital modes - it
distorts the signal and reduces copy capability..
The digital decoding is happy to extract a signal from the noise - some
more so that others, and some data modes can extract a signal
significantly under the noise level, so NR is inherent in the digital
decoding.  You can try it, but I suspect your digital reception will be
reduced with the presence of external DSP NR between the K3 and the
computer soundcard.

This is not intended to put a damper on your experiment, so give it a
try and let us know the results.  If you can provide some repeatable
stimulus and output data with the no DSP vs. the DSP added, that would
be informative and useful.

73,
Don W3FPR

On 12/24/2011 5:08 PM, Jim Harris wrote:
> 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
>
>
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[Doug 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" <[hidden email]>
To: "Elecraft Email" <[hidden email]>
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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[Rick Prather-2]

Doug,

Sounds like a great set up.  

If someone happens to be on a Mac a very effective and simple way to accomplish much of the same thing is to run cocoaModem which will display two receivers on the main screen with two waterfalls in Wideband RTTY.  

Very useful for watching the pile up on the Sub and the DX on the Main.

Rick
K6LE

On 12/25/2011, at 5:57 , D Joyce wrote:

> 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
>

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[radioshoppe]

Doug,
Thank you very much for the input.  Even though your DSP is a different brand from mine, the hookup information is valuable.  Sometime this week I will try to find time to get it hooked up and maybe I can find some RTTY on the bands for testing.  I'm sure I will need to go to the local electronics store for cables and connectors to get it all connected together.  A good excuse for warming up the soldering iron.
Just for funs and grins I also have a Heathkit Active Audio Filter, model HD-1418, hooked up to my K2 which is the second radio in my RTTY contesting SO2R setup.  With our postage stamp size lot of 80 X 90 feet in a residential area I don't have the luxury of big antennas so I tend to have low signal levels and high noise.  I'm really hoping these additions are going to help bump the RTTY score up a bit.  
For those that have seen Don, W3FPR's response to my previous message.  We have corresponded off line and I think we are on the same wavelength.  Both of us are waiting to see how this idea will work out.
Thanks guys for the input.

Take pride in the USA. 73



Jim, W0EM

--- On Sun, 12/25/11, D Joyce <[hidden email]> wrote:

From: D Joyce <[hidden email]>
Subject: Re: [Elecraft] K3 RTTY Audio Thru External DSP
To: "Jim Harris" <[hidden email]>, "Elecraft Email" <[hidden email]>
Date: Sunday, December 25, 2011, 1:57 PM

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" <[hidden email]>
To: "Elecraft Email" <[hidden email]>
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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