SAQ 17.2 kHz Christmas Eve Transmission

I was finally able to capture and listen to SAQ this morning. I used the KiwiSDR and a new 350 foot beverage antenna. I have been trying to receive this station since 1981.

Thanks to Jim Lill WA2ZKD and Rob Robinett AI6VN for getting me enthused enough with KiwiWSPR to put up the new antenna.

Steve KD2OM


  • Congrats.... I have been hearing Steve lament for 30+ years not hearing it.
  • Here in northern Sweden, SAQ was very strong. Distance to SAQ transmitter is about 1100 km. Interestingly, SAQ was audible / visible with a weak signal also when the transmitter was in key-up position. Obviously keying relay insulation is a bit poor. However I suspect that the transmitter might be out of warranty...


    Mauritz / SM2BYC
  • The key-up signal, called a "backwave" years ago, is a result of the magnetic amplifier that provides the keying. The actual alternator (tx) stays on continuously but is switched between the antenna and a 'dummy load' by the keying. This keeps the alternator from experiencing what would be terrific mechanical stress. As you note, that keying isn't perfect.

    If you or others on this forum ever have a chance to visit Grimeton (near Varberg and Göteborg), do it! I had a wonderful visit and tour hosted by Lars (World Heritage site manager there) a couple of years ago and truly enjoyed it. It's a rather long trip for you though, 113 Swedish miles, 1125 km !

    I couldn't actually hear it on a 1.8m dipole, 1.5m above ground here in Colorado but I could barely see it in the waterfall. However I was very happy to be able to use a Kiwi at SK6AG who heard it *very* well. The waterfall display showed the spectral line width to be significant most of the time, several 10's of Hz during the message, which made it a bit harder to see from locations where it was very weak, such as the western US. But it was 'seen' (not heard by ear) on a Kiwi in California. W0BC in central Colorado reported hearing it part of the time. I guess I need to work some more on the VLF antennas for the Kiwi here!

    Pretty amazing for rotating machinery that is more than a century old.

    Glenn n6gn
    Fort Collins, CO
  • What made the difference for me is the 350 foot beverage antenna. At the moment it uses a KD9SV transformer and a 450 ohm termination. I don't think the transformer is the best for such a low frequency so am going to wind a transformer with a core that will be better for 17 kHz. I was able to see and hear the signal with the KiwiSDR, but also copied it on an RF-590A receiver and saved the wav file with two KiwiSDR's, one closeer to the transmitter.
  • From where were you listening?
    Glenn n6gn
  • Steve is in Victor NY, a rural area SE of Rochester
  • FB. That path is physically a lot like the original path from SAQ to the US. The antenna may even be similar, though I've misplaced my Alexanderson book and can't verify that. I think there were multiple Beverages, pointed like a star, to the other locations worldwide.
    Glenn n6gn
  • WA2ZKD/1 in Maine with Kiwi and Pixel Loop did NOT hear it
  • edited December 2018
    has anyone attempted to use their PC soundcard microphone input connected to their antenna with the sampling changed from the default 44.1Khz to 192Khz ?
    this works good as a baseband I/Q for VLF down to audible frequencies. (if your software can support frequencies that low)
  • >
    >has anyone attempted to use their PC soundcard microphone input connected to their antenna

    Yes I have tried receiving several VLF stations using just a PC soundcard.

    There is a some very simple receiver software, primarily designed for SAQ transmissions

    But other more sophisticated applications such as spectrum lab have a preset VLF receiver mode.

    Mains hum, ground loops and noise pickup from the PC data lines are the main issues when using a sound card.

    I got the best results using an Icon Cube Pro USB soundcard 4ch with 196KHz sampling on a USB extender cable. But I find that unless you are really interested in extremely low level sub 10KHz signals the KiWi does a pretty good job.


    Martin - G8JNJ
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