Contesting With SDR

This past weekend I had time to play in the North American QSO Party (NAQP) with my new SDR Attachment to my FT-950. The results in my book are mixed. There were two reasons why I wanted the FT-950 to go along with a SDR. The first and most important reason to me was to have a band scope. The second reason is to take advantage of the filtering done by the software.  I wanted to apply both of these features to contesting to hopefully improve my search & pounce QSO rate.

At the moment of writing this I am using SpectraVue software to display the SDR as well as controlling the VFO of the FT-950. SpectraVue is an excellent piece of software but is very basic. It has some software filtering but doesn’t compare to HDSDR or SDR-Radio. I prefer SpectraVue because  it’s minimal and runs smoothly on my somewhat dated computer (Quad core AMD @ 2.3Ghz, 4GB Ram, ATI [512Mb memory] video card).

For contest logging I use N1MM. My personal opinion is that N1MM is hands down the best software for contest logging. The software has so many options that it’s difficult to find something that it can’t do. It has so many options that some people think it’s too much and won’t use the software. It’s free and there is a huge community that is there if you were to find yourself in trouble. It maybe overwhelming at first but it’s not that hard to setup and use.

Here is a really horrible sketch of my setup for HF for those who are wondering.


Running N1MM and SpectraVue that both want to control the radio leads up to an issue. The serial port is currently being used by one piece of software which blocks out the other software from controlling/reading the radio.  There is a way around it by using another piece of software call a “Virtual Com Port”. The fine people that make the LP-Pan has thought of this and released software called “LP Bridge” that will allow multiple software to use the com port all at the same time. It works well and it’s free! There is also “Virtual Serial Ports Emulator (VSPE) ” that also does the job but is not free.


When everything is up and running and your hardware is working with your software and your software is working with your hardware, you will have a busy screen.

NAQP on 20M

Here is my small computer screen sharing N1MM with SpectraVue.  In the center you will see SpectraVue displaying 200Khz worth of bandwidth from 14.814Mhz to 14.344Mhz which is the majority of 20M voice band. What you see is a “Water Fall” with conversations trickling down the screen and the waveform of the signal above the waterfall. Just by glancing at the waterfall you can have an idea on how busy (or dead) the band is. You can also tell how strong some of the signals are by their brightness compared to other signals. By clicking on the left side (or right if using LSB) of a displayed signal, you will focus the receiver to that conversation. Depending on your setup, the radio will also change its VFO to that frequency so you can initiate contact.

Mixed in around SpectraVue you will see N1MM software also running waiting for me to log contacts instead of taking screen shots.

NAQP 2013 40M

Here is a shot of what 40M  (7.1MHz – 7.3MHz) looks like during NAQP

I will say that having a panadapter does help me (and possibly you) when It came to search and pounce contesting. Instead of spinning the dial looking for a station, I can now just click on a station and the software and radio will do the rest. It has improved my QSO rate much better.

It’s not the best thing since slice bread. 

I just want to add that I did have an Issue when it came to contesting with SDR capabilities.  It may be just an issue of mine but I have a feeling it applies to anyone with a similar setup. One of the great things about SDR is to let the computer and its software to do the filtering instead of the radio. It could allow you do use all different kinds of filters and filter widths that could really pull that signal “Out of the air”  When I’m using the SDR standalone, there is no problem what-so-ever. But when you hook it up to the radio that is already processing the signals, It’s very clear that there is a delay between the two. That is because of the SDR and computer are processing the signal coming out of the radio and takes longer than the radio.

In contesting that delay is annoying. More so if you have the volume up on your radio. In the cut throat world of contesting and chasing DX. That delay will end up costing you points and some angry ops (when isn’t there angry ops) because you’re not in-sync with them.

It’s not the end of the world. I found that using the audio from the radio and using the software as band scope proved to be beneficial.

Not sure about CW contesting. 

At this point I am in the early stages of learning CW so I am unable to comment on anything having to do with CW. I am going to assume that it just like voice contesting. Zoom in until you see all the CW and click on the signal you want to make contact with.

I’m in dream land again!

If I had the skills I would love to have software that is designed for SDR contesting. Combine the logbook and waterfall into one impressive package. Then allow to do digital work like PSK and RTTY on the same waterfall.

Thanks for reading,

Jeff – NT1K


One thought on “Contesting With SDR”

  1. LP-Bridge seems like a lot of work. If N1MM would accept connections from a DDE client like HDSDR that would be much cleaner, I think. Right now having to use LP-Bridge and OmniRig to let both N1MM and HDSDR to sync with the transceiver (K3 for me) seems very bulky. I tried LP-Bridge with HRD Rig-Control and it crashed my Windows 7 64 system.

    Regarding the delay. Yes unless all sound cards are using ASIO or similar drivers you’ll get a lot of delay. I generally just use the audio from the transceiver and let HDSDR show me what’s happening and also control tuning on the rig.

    The display also helps to find a free spot to call CQ.

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