Future Development

Hi everyone,

now that the Audio Spectrum/Waterfall feature is done and it’s as good as I wanted it to be it’s probably time to work on improving some of the other modules and develop new ones.

The first one that probably needs some fixing is the SWR Meter one. Some people is still having problems with it and I need to work on making it more stable and efficient. In some cases it seems that it is not able to read well the SWR values and in some it does crash before starting to do the sweep.

To make that I want to first development a new module that I want to name “TUNE Helper“. It is intended mainly for those like me, owning an Alexloop that needs to be adjusted to be resonant. The idea is to give an audio feedback so that you can “listen” to the SWR value while tuning.

Also want to improve the QSO logging feature by adding:

  • easy cleaning of the data fields in case of an aborted QSO
  • support for QRZ.com XML or Hamlog so that as soon as you write the call, all the other fields (name/QTH/Locator) are filled with the available information. That would require an Internet connection
  • eQSL support, so that as soon as a QSO is logged, the log is sent to eQSL as well. This requires an Internet connection as well.

I’ll also add a DXCluster feature. I found some nice API that can make the thing easy to integrate in the app. I’ll surely add a touch QSY feature so that simply by touching the DXCluster entry, the KX3 switches to the spotted frequency. I’ll try to add a map showing spots as I’ve seen that I got latitude/longitude information for most of them and I think it’d be a nice cool feature.

I’m also studying to integrate two TX modes.

One is WPRS. I have all the documentation needed to generate a WPRS transmission. Lately I’m working a lot with WPRS and I think that can be a very useful feature to add, to test setup efficiency. It’ll be a transmission only feature for now. Leaving for a future stand alone app, the receiving side. To check results I’ll integrate a couple of WPRSnet.org pages.

The second mode is QRSS (very slow CW). I find it intriguing and want to work on that as well. It’ll be a beacon feature so sending only. At least for the module that I want to integrate in the KX3 Companion app. Maybe that, as for WPRS, sooner or later I’ll be able to develop a stand alone app that will also be able to receive QRSS and so able to manage a QRSS QSO.

Coming back to the Spectrum/Waterfall feature, one important thing is still missing and it’s the full I/Q analysis so to create a real panadapter showing both sides of the band. There’s a technical problem that I’m trying to overcome. The fact is that most (all I know) jack output/input in Android devices integrate mono microphones.

They are TRRS connectors, standing for Tip, Ring 1, Ring2 and Sleeve.

As shown in a previous post, Tip and Ring1 are dedicated to left/right audio out, Ring2 is the ground and Sleeve is for the microphone (audio in). So only one channel is for microphone meaning that we have a mono audio in.

Actually Android doesn’t natively support USB Audio, but needs some commercial driver to use USB audio cards. iOS has an advantage here as you can quite easily attach a USB audio card to an iPhone/iPad and so have a stereo audio in. I used it in the past and works perfectly. Android doesn’t… actually. That would mean no panadapter on Android (unless using commercial drivers that cost definitely way too much for me!).

But I’m trying a workaround.

The workaround is to use Bluetooth A2DP (Advanced Audio Distribution Profile). Probably you’ve seen or heard os Bluetooth dongles that wirelessly stream audio from your smartphone/tablet to A2DP headsets, car audio or to general A2DP receiver that can be attached to almost anything.

And A2DP is supported by Android.

So the idea is to attach an A2DP transmission dongle to the KX3 RX I/Q port and receive it with the smartphone/table.  I just ordered the dongles and I keep finger crossed 😀

With the stereo audio in working, it’d be a matter of a couple of days before having the panadapter working. I should not be able to go beyond 44.1/48 kHz bandwidth but that’s a more than good in my opinion.

A2DP transmitter dongles are now quite cheap (around $20-$25) and that would be a worthwhile investment to have a 48kHz panadapter on a tablet.

I also decided that most of the above features will be deployed as in app purchases so that everyone will be able to decide if and which module to have based on his/her needs.

That’s a lot to come 😀

Any feedback or additional idea is more than welcome as usual. Thanks a lot to all those already doing that and most of the above ideas come from them.

72/73, Andrea IU4APC


6 thoughts on “Future Development

  1. Hi Andrea,
    I’m wondering if, with a sample rate of 44/1/48K, your useful bandwidth might be considerably less.

    In digital Audio stuff 44.1K really means a top end of about 20K and even then, that’s less than a hand full of sample points for a sine wave input at the higest frequencies. I don’t know how number of samples affects I/Q decoding but it very well may.

    The KPX3 advert says about 200K bandwidth for that product. I think even a band width of 10K for digital modes would be way helpful and most likely folks would want to get in even closer to help seperate out those pesky PSK signals.

    Just some thoughts….


    • Ciao John,

      don’t think so. I’m already working with 48kHz sample rate but it’s mono so I have a bandwidth of 24kHz. If you look at the spectrum/waterfall you can see that about 90% of the bandwidth is usable, so working with 44.1/48 kHz full bandwidth I expect to have at least 40kHz of good signal.

      That is the maximum bandwidth, but as it is already now, you’ll be able to select the bandwidth range that you prefer. Actually, with mono, you can go from 2 to 24 kHz. With both I/Q you’ll have from 4 to 48 (or 44).

      200kHz is a good range but not very workable. Only if you want to monitor the whole band for ham radio. But I’m sure that most of the time, people will use smaller ranges.

      With a cheap RTL2832 DBV-T USB Key you can reach up to 3.2MHz bandwidth. I use them every day and I never found useful to have such a wide range.

      Andrea IU4APC

    • I’ve been using the WF/SPEC feature for a couple of days now and find 8Kz view to be most effective for me, but often do a quid 24Hz overview to get into a ‘range’.

      There will always be trade-offs in any scenario, so far the only thing that would be a needed improvement is both sides of the band, but even that hasn’t been too disturbing.

      The WF.SPC plugged right into the IQ-RX port has opened brand new capabilities of my KX3 I had never even thought of before!


      • Me too… 8kHz is the range I use most but having the chance to see both side of the I/Q would be great. I use HDSDR on the PC and it’s a real plus. Having the same features on the Nexus 7 (full screen) would be great.

        Andrea IU4APC

  2. All I can say is WOW!!!!

    Very much looking forward tp the new features. And YES YES YES to QRSS!!


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