Elecraft KX3 NaP3 Configuration Highlights

In mid November I sold my Kenwood TS-590 to finance the purchase of an Elecraft KX3 and become a full time QRP operator.  One of the advantages of the KX3 is SDR I/Q output, which can be used to drive a panadapter.  After some fidling around, I have a configuration that works with the popular NaP3 software and thought I would share the highlights in hope of saving you some effort.  This is by no means an exhaustive setup and configuration guide for NaP3, but it should be enough to get you started.  Remember you can click on the images to enlarge them.

For this example I have used the integrated sound card in my PC and have not yet put a ground loop isolator inline which are both opportunities for improvement.


NaP3 Audio In Advanced Tab

NaP3 Audio In Advanced Tab

We begin by manipulating the input sound card port configuration as shown above.  This will vary somewhat from sound card to sound card, but we want to be sure that we are capturing two channels and that the sampling rate is set at the maximum your card supports, which may take some experimentation and is not necessarily the highest sampling rate shown in the drop down.


NaP3 Setup Tab

NaP3 Setup Tab

Here on the setup tab of the NaP3 configuration, we need to select the sound card input we are using and where we would like NaP3 to output decoded audio.  Once again we have the option to manipulate the sampling rate, which as you can see is 48k for my sound card.  In addition, we need to select “Elecraft K3” for the Rig Type and specify our CAT parameters.  I began this adventure trying to use the “Elecraft KX3” Rig Type, but I found it to not work very well.


NaP3 IF Tab

NaP3 IF Tab

Here is the “fun” part, at least it was for me until I started banging my head on the desk.  Be sure to set your “Global Offset” to 0 and select “Swap I/Q Channels”.  The “IF Frequency Offsets” is where you will have to spend some time playing.  The method I used was to tune to WWV in CW mode on the KX3 and determine the differential between the frequency displayed on the KX3 and the panadapter display.  I then set the offset to compensate.  To configure the offset for USB and LSB modes, I reduced the offset by the amount equal to my CW sidetone.  This should get you pretty close, but may still require a little tweaking.  Feel free to try my numbers, but I am unsure if they are valid from KX3 to KX3.

If you determine some other method to set the offsets, please let me know as this is the most time consuming portion of the configuration.


NaP3 Spanadapter View

NaP3 Spanadapter View

When it is all over, this is similar to what you will end up with, a nice broad view of the spectrum centered on your rigs current frequency!

Robert Garcia, K5DTE, is a regular contributor to AmateurRadio.com and writes from Arkansas, USA. Contact him at [email protected].

7 Responses to “Elecraft KX3 NaP3 Configuration Highlights”

  • Mike Ve3wdm:

    Good evening Rob, great work and thanks for the info regarding the setup. I have been wanting to get the KX3’s SDR up and running but at this point I am still playing with some software and the Mac computer.

  • Thanks Mike!

    I found many different variations on the configuration for NaP3 with the KX3 and thought I would add another. It seems to be stable and I have not had any issues.

    It is currently setup using LP-Bridge, so the CAT data can be shared between NaP3 and Commander/DXKeeper for normal operations and for contests, I can feed data to N1MM.

    I have glanced over the osX options and they don’t seem to be as numerous as the ones available on the Win platform, but I’m sure you will find something!



  • Mike Ve3wdm:

    Rob I have purchased Parallel Desktop 8 that allows me to run WinXP and Mac on the same PC. I have given it a dry run and all seems to be working great I am now going to give some ham radio programs a go.

  • NY4G:


    Thanks for your helpful tips. This got me really close out of the box. I find that I don’t even need N4PY except on my K2 since it does not have IF. The KX3 is a great little rig.

    Ariel NY4G

  • Steve K7EW:

    I am not as experienced as I wish. I have a KX-3 and a Mac OS-X 10.6.8. Are there pretty-much step-by step instructions, of any additional hardware I would need, and the computer set-up sequence? – Would some of it come from the NaP3 site?
    tnx es 73, Steve

  • James Sheehan kC1CS:

    hI just got my new KX3 and having problem with tje setup using NAP3 softwaare. When I tx it seems to be right on center but on rx I seem I see signal both on left and right of center .I no dummy been a ham for 30 years but this little guy has me stump anyone please Help me age hr is 64 so I had flex 3000 1500 and 5000 no problem running them but this little guy all I can say is I need help with the setup.

    Thank You

    KC1CS James

  • Fiete & DGR277:

    i am glad, that all this exist.

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