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Discussion in 'Amateur Radio News' started by VK2BVS, Dec 22, 2008.

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  1. VK2BVS

    VK2BVS Ham Member QRZ Page

    The VERY LOW FREQUENCY station in Sweden, call sign SAQ will be using CW (Morse code) on 17.2 kHz and will start transmitter tuning at 0730 UTC.

    VLF station SAQ (now a member of the Swedish Amateur Radio Association) will be on air Wednesday 24th December 2008 at 0800 UTC and 0830 UTC.

    Anyone with a computer can download the free Computer Soundcard Based SAQ ELF (Extremely Low Frequency 300 Hz to 3 kHz) and VLF (3 kHz to 22 kHz) Receiver from Johan SM6LKM on

    Connect a long wire into the computer microphone socket.
    I use a 1.8 MHz half wave dipole.
    Disconnect the antenna before a storm and when not in use to avoid lightning danger.

    The next test after this one will be on Sunday 28th June 2009.
    Listeners can send QSL’s via the bureau.

    A Merry Christmas and a Happy New Year to all.

    Sam Voron VK2BVS, 6O0A.
  2. K5CO

    K5CO Ham Member QRZ Page

    I confess, it never occured to me to use the input to the sound card for such; I have to try that.
  3. KA5S

    KA5S Subscriber QRZ Page

    The AOR 5000 tunes to 5 KHz. However a SC will do DSP averaging. Hmm. I have a loop antenna for that low. Maybe I'll try it.

    Last edited: Dec 23, 2008
  4. NC5P

    NC5P Ham Member QRZ Page

    This program seems to work with Wine, so MAC (Intel) and Linux folks can try it. I only wish we could tune higher but our sound cards are too slow.
  5. VK2BVS

    VK2BVS Ham Member QRZ Page


    This test was a great opportunity to do more VLF listening.

    I always enjoy listening on the ULF Ultra Low Frequency band 1 Hz to 300 Hz, ELF Extremely Low Frequency band 300 Hz to 3 kHz and VLF Very Low Frequency band (3 to 30 kHz).

    My last great catch was an 8 kHz transmission from a VLF transmitter/receiver water pipe leak locator that was used by a plumber searching for the location of a water leak from pipes under my garden.

    Using the SAQ receiver and a 1.8 MHz antenna I was not able to hear the test transmission from SAQ Sweden on 17.2 kHz in Roseville, 6 km north of the Sydney harbour bridge during my local Australian daylight afternoon summer time.

    I did hear the Australian North West Cape submarine broadcast station in Western Australia on 19.8 kHz at signal strength -65db and the Russian submarine broadcast station on 18.1 kHz at signal strength -75db.

    There is a story about the SAQ Very Low Frequency Sweden transmitter and antenna in the current ARRL QST magazine January 2009 on page 38.

    Station SAQ Sweden use no valves and no transistors to generate 200 kW (200,000,000 Watts).

    They do this with a mechanical AC generator which was the technology to generate high power radio waves before valves and transistors were invented.

    The VLF station is maintained as an emergency communications system to communicate with Swedish submarines in the Atlantic Ocean and elsewhere.

    In the event of an electro magnetic pulse capable of destroying transistor radios it seems that Sweden is maintaining this very interesting VLF transmitter in case all else fails.

    What did you hear?

    Sam Voron VK2BVS, 6O0A
  6. KA5S

    KA5S Subscriber QRZ Page

    Good stuff Sam. Me, I didn't wake up in time. Ah well, there's 90cm of snow out there and dragging the loop away from the house would not be fun in the dark. If I leave it out it will need waterproofing.

  7. N1NKM

    N1NKM Ham Member QRZ Page

    I would suspect that you'd want to do SOMETHING to eliminate the INTENSE interference you're going to get from the local power lines. :mad:

    What do you usually hear from an audio amp when you touch (or connect only one wire to) an input? Usually, a very loud hum or buzz from your AC power. That's most likely want your sound card is going to "hear" as well. :(

    A small audio transformer used as a choke to computer ground should be enough to allow audio frequencies above a few hundred Hz while greatly attenuating that low freq noise from the AC lines. (Use a capacitor between the input and your antenna, like .1 or .05 ufd.) Also keep in mind that the AC line noise conatins MANY harmonics! :eek:
  8. VE4CY

    VE4CY XML Subscriber QRZ Page

    This has me intrigued.. I listen to just about everything including the non directional beacons below the AM broadcast band from 200 to 530 Khz.

    I've got a full sized 160 meter dipole, but a quick calculation shows it's less than 10% of a half wave at 17 Khz.... (Using it is kind of like using a 2 meter dipole to recieve signals on 20 meters) :) I guess the optimum antenna would be some sort of giant receiving loop, but I haven't got the energy to actually assemble one.

    When I get into the city this weekend, I'm going to pick up what I need to assemble a PL259 to 3.5mm adapter so I can plug my antenna directly into my sound card and see what happens.
  9. VK2BVS

    VK2BVS Ham Member QRZ Page

    Listening to VLF in the snow.

    Hello KA5S,

    Sounds like you have a great Christmas antenna thing to do.

    Better than building a snow man?

    Here in Sydney we never see snow.

    Its now 78 degrees, a sunny normal Christmas day.

    Great for VLF listening.

    Keep warm up there.

    73 from down under,

    Sam VK2BVS, 6O0A.
  10. AF4KK

    AF4KK Ham Member QRZ Page

    This is FASCINATING! I have to try to listen to the next test in June!! It's hard to find a radio that's not deaf below 100 kHz but I think my AOR AR8600mkII with a VLF converter will be my best bet!
  11. VK2BVS

    VK2BVS Ham Member QRZ Page

    No power line noise problem on VLF in Sydney, Australia.

    Hello N1NKM,

    I am pleased to report I have enjoyed VLF listening in the city of Sydney free of power line noise problems.

    I live in the residential northern suburbs of Sydney, 6 km north of the Sydney harbour bridge.

    240 Volt and 11,000 Volt electricity power lines run along my street parallel to my house.

    The power pole next to my house holds a large power transformer.

    My 1.8 MHz antenna is parallel to the power lines and one end of my antenna is only 4 metres away from the power pole that is holding the large power transformer with 240 Volt and 11,000 Volt Street electricity wires (plus cable TV).

    I have had power line noise problems from time to time on LF, MF, HF and VHF but VLF has been free of those problems

    I have no serious power line noise problem on VLF (0 to 22 KHz on the SM6LKM SAQ downloaded VLF receiver on

    There is also no power line noise problem on the Kenwood TS480HX which receives between 20 kHz to 30 kHz. I use the 10 kHz clarifier to listen below 30 kHz.

    I have found that the TS480HX noise reducing features are not needed between 20 kHz to 90 kHz.

    To use the TS480HX between 20 kHz to 90 kHz the receiver preamplifier must be in the NORMAL position. If you have the TS480HX Preamplifier ON it will stop VLF signals (the preamplifier was not designed to amplify VLF signals).


    The SM6LKM SAQ downloaded VLF receiver has a higher back ground noise level on 0 Hz to 22 kHz since it is more sensitive compared to the TS480HX receiver on 20 kHz to 30 kHz. This is because you must switch the TS480HX preamplifier OFF to hear VLF signals.

    The signal strength noise floor WITH NO ANTENNA connected to the SAQ downloaded SM6LKM VLF receiver is displayed on the spectrum scope (the spectrum scope is included as part of this free VLF receiver). The signal strength compared to the frequency is as follows-

    Frequency (Hz, kHz) and noise signal strength (minus db).
    An increasing minus db number means a smaller signal strength (or lower noise level).

    0 to 300 Hz minus 70 db (is a decrease in noise).
    300 Hz to 1 kHz minus 90 db (is the maximum noise).
    1 kHz to 20 kHz minus 95 db (is even less noise).
    20 kHz to 22 kHz minus 100 db (is the least noise)

    CONNECTING A 1.8 MHZ ANTENNA to the SAQ downloaded SM6LKM VLF computer program sound card based receiver raised the noise level to the following signal strength levels-

    Frequency (Hz, kHz) and noise signal strength (minus db).
    An increasing minus db number means a smaller signal strength (or lower noise level).

    On a frequency of 1 Hz the signal strength was minus 30 db. (This is the noise (buzz) level from the 50 Hz (in Australia) power line electricity AC).

    50 Hz minus 25 db (is the operating frequency of the power line AC in Australia. This frequency has the largest signal peak. It is the highest noise (buzz) signal level). Note that 60 Hz is used in the USA electricity system.

    280 Hz minus 50 db (is the first detectable noise reduction on a frequency between the power line AC noise (buzz) harmonics above 50 Hz).

    420 Hz minus 38 db (is the second detectable peak in the power line AC noise (buzz) signal level).

    580 Hz minus 58 db (is the second detectable noise reduction on a frequency between the power line AC noise (buzz) harmonics above 50 Hz).

    1 kHz minus 58 db (is the power line AC noise (buzz) signal level).

    1.480 kHz minus 70 db (is a quite spot with low noise).

    2 kHz to 5 kHz (is where the noise level drops from minus 65db on 2 kHz to minus 83db on 5 kHz).

    6 kHz to 10 kHz (is where the noise level rises slightly to minus 80db).

    10 kHz to 20 kHz (is where the noise level drops from minus 80db to minus 90 db).

    20 kHz to 22 kHz (is where the noise level is at the lowest at minus 95db).

    The region from 1 Hz to 1 kHz has the highest noise level.
    The region from 2 kHz to 22 kHz has the lowest noise level.

    Happy noise free VLF listening

    Sam Voron VK2BVS, 6O0A.
    Last edited: Dec 26, 2008
  12. VK2BVS

    VK2BVS Ham Member QRZ Page


    Hello VE4CY,

    You can download the complete VLF receiver program for free. It makes any computer become a VLF receiver.

    I am pleased to report great success listening from 0 to 30 kHz using my 1.8 MHz half wave inverted V dipole antenna.

    Using the 1.8 MHz (160 metre amateur radio band) antenna I can hear VLF stations thousands of miles away at 10.48am Sydney Summer Time. This is at a time when the higher frequencies (known as the AM Medium Wave broadcasting band) will only allow you to hear stations 300 miles away.

    At 2348 UTC on 26 November 2008 I heard-

    18.1 kHz Russian submarine navy broadcast station, signal strength minus 72 db.

    18.2 kHz India submarine navy broadcast station VTX3 Vijayanarayanam village, fading in and out from maximum signal strength of minus 80db down into the noise level at minus 90 db (the weakest of the signals).

    19.8 kHz Royal Australian navy submarine broadcast station, North West Cape, Western Australia signal strength minus 62 db (the strongest of the signals).

    21.4 kHz American submarine navy broadcast station NPN Hawaii, signal strength minus 82 db.

    The 1.8 MHz antenna actually works from 0 to 90 kHz.

    I have been using the Kenwood TS480HX (with the receiver preamp in the NORMAL position because the preamp is not designed for VLF signals) on the Very Low Frequency (VLF) band from 20 kHz to 30 kHz.

    I have heard the following Low Frequency (LF) 20 kHz to 90 kHz signals-

    22.2 kHz Call sign JJI, Japanese Navy submarine broadcast station, Kyushi, Ebino, Japan

    25.0 kHz Russian Navy submarine broadcast station, Russia.

    Using the Kenwood TS480HX on the Low Frequency (LF) band between 30 kHz to 90 kHz I have heard at night-

    40 kHz Call sign JJY, 50 kW Japan 40 kHz time signal station, Morse code identification at 15 and 45 minutes past the hour, Hagane-yama Mountain, Japan.

    54 kHz Call sign NDI, 250 kW ERP, U.S. Navy submarine broadcast station, Awase Peninsula, Okinawa, Japan.

    60 kHz Call sign JJY, 50 kW Japan 40 KHz time signal station, Morse code identification at 15 and 45 minutes past the hour. Hagane-yama Mountain, Japan.

    68.5 kHz BPC China with regular pulse broadcasts.

    When not calling CQ on my 1.8 MHz 160 metre band amateur radio antenna it is great to use it to listen to the ULF (1 Hz – 300 Hz), ELF (300 Hz – 3 kHz), VLF (3 kHz – 30 kHz) and LF (30 kHz – 300 kHz) bands and have worldwide reception especially considering that it is designed for the MF (300 kHz – 3 MHz) band segment of 1.8 Mhz.

    My 1.8 Mhz (160 metre band) antenna is a half wave dipole inverted V antenna connected to 50 ohm coaxial cable. It looks like the letter V upside down.

    This antenna is 30 feet high in the centre and the antenna ends are 10 feet above ground

    It is actually a multiband antenna because I have connected 3 other half wave dipoles (3.5 MHz, 7.1 MHz and 10.1 MHz) to the same cable. This with 160 metres makes it a 4 band (160, 80, 40 and 30 metre band) antenna on one coax cable.

    The 1.8 MHz antenna will also work on VLF if you disconnect the antenna earth by unscrewing the PL259 outer plug.

    Here is an idea to help everyone build a 1.8 MHz antenna.
    Get the wire and run it along your fence, on the ground or/and up and down a tree.
    Do anything, put it anywhere and now try listening on VLF.

    73 and enjoy the world of Very Low Frequency exploration,

    Sam Voron VK2BVS, 6O0A.
    Last edited: Dec 26, 2008
  13. K2ND

    K2ND Ham Member QRZ Page

    VLF reception

    Interesting stuff, I am sorry I missed the test.

    VLF receive antennas are less fussy than most think. A simple vertical wire works very well, especially since most VLF transmitters use a vertical antenna. My 80 meter quarter wave works very nicely.

    Many excellent VLF systems use a short CB style whip antenna with a very simple pre amp in the base. This gets around the noise problem most of us face, by raising the signal level before it gets in the feedline. As with any vertical antenna, placement of the antenna and creating a good radial system is crucial. Place the antenna out in the clear and as high as possible. VLF manmade noise diminishes quickly with height. Place the vertical on anything conductive: a tin roof works well, but even a garbage dumpster or chicken wire will do.

    Do not worry about the length of the antenna so much, just pay attention to placement and the grounding. And use a balanced and shielded style feedline if possible to minimize coupling to local noise sources.
  14. VK2BVS

    VK2BVS Ham Member QRZ Page


    If you listen on VLF and hear nothing but noise this can be because the antenna connection to the stereo plug (if you are using a computer as a VLF receiver) is on the wrong channel or it can be because the antenna is not working.

    Here is a way to check if the noise you hear is VLF.

    If you are using the SEQ downloaded computer VLF receiver then tune to 50 Hz (in Australia) or 60 Hz (in the USA). If you cannot hear the electricity buzz from the outside power lines then you know that the connection or the antenna is the problem.

    Listening from 1 Hz to 1 KHz during a power failure would be great fun if you have a UPS power source. You could then listen free of power line buzz on the Ultra Low Frequency ULF (1 Hz – 300 Hz) band and on the lower end of the Extremely Low Frequency ELF (300 Hz – 3 kHz) band.

    If you have an Uninterrupted Power Supply UPS you were going to trash then drop it in here and I will give it a home until the next power outage. Now all I need is a UPS and an electricity failure to do more exploration below 1 kHz.

    A loop antenna can be used to null out power line buzz below 1 kHz if you cannot wait for a power black out.

    If you cannot listen on 50 Hz or 60 Hz then listen on any frequency from 1 kHz to 30 kHz.
    You should hear occasional short duration atmospheric static.
    Modify your antenna or try a different antenna if you cannot hear any short duration atmospheric static.
    Try the vertical antenna outlined above by K2ND and the 1.8 MHz horizontal dipole antenna outlined earlier.

    Which antenna worked best for you on VLF?

    Sam Voron VK2BVS, 6O0A
    Last edited: Dec 26, 2008
  15. VE4CY

    VE4CY XML Subscriber QRZ Page

    I downloaded the sound card software, but missed the test :( (Too much to do this time of year).

    I have one of those portable power supplies with an internal 6 Amp/hr gell cell. I live in the country and there aren't too many people around me so power line noise isn't as bad as in a large city.. Last summer we had a major, wide scale power outage. The first thing I did was connect the gell cell to my receiver and listened down low.

    I have a signal generator, so not only can I check to see if the sound card receiver works, I can also check its accuracy.

    Out of curiosity....... Did anyone manage to hear the Swedish test transmission?
  16. N1NKM

    N1NKM Ham Member QRZ Page

    OK, I've downloaded that tiny software and ran it. Amazing! :) Now, to build a basic coupler/protection ckt, and hook up an antenna! This should be interesting!
  17. VK2BVS

    VK2BVS Ham Member QRZ Page


    Hi VE4CY here are the test transmission results,

    Hi N1NKM here are some VLF internet receivers that will give you an idea of what frequencies are active.

    The SAQ Sweden Morse code (CW) test transmission on 17.2 kHz was heard in Russia (Moscow), England (Sheffield), Portugal (Lisbon) and the USA (Boston).

    The spectrum display of some of these receivers are on the Internet site of the World Wide Lightning Location Network WWLLN

    For example if you click on the Brisbane (Australia) Very Low Frequency receiver spectrum display you can expand the image and you will see the frequencies along the vertical axis.
    0 kHz is at the bottom and 24 kHz is at the top.

    The horizontal axis shows the time. You will see a yellow horizontal line below 20 kHz. (That was the colour when I saw it at 0200 UTC, the colour indicates the signal strength). This is the spectrum display of the VLF signal of the 1000 kW Royal Australian Navy submarine broadcast station at Exmouth, North West Cape, Western Australia on 19.8 kHz.

    Good listening!

    Sam VK2BVS, 6O0A
  18. VQ9LA

    VQ9LA Guest

    LF band (10 to 300 kHz) upconverted to HF Receiver

    If you want to use a real radio. Here is a very cheap kit.
    The kit claims to use IF's in the ham bands and tune the LF band (10 to 300 kHz) which will be upconverted to HF
    Most Ham Receivers are Deaf below 400khz
    the site also has the LF Converter Schematic Diagram and manual. If you have a lot of parts in your junkbox it could be homebrewed for nothing.
    73 and HNY see you in the CW Pileups
  19. KD6IQS

    KD6IQS Ham Member QRZ Page

    listening to these frequencies

    Hello to all,

    I just stumbled upon this thread and am rather interested.

    I own an Icom PCR-1500, which will receive down to 10 KHz and its connected to several antennas (one of which covers down to 10 KHz).

    I guess my primary question is, what mode are most of the transmissions
    in the 10 KHz to 100 KHz range (AM, SSB...?) I've spent numerous hours scanning these frequencies for any kind of transmission but just don't seem
    to find anything but static. :(:confused:

    So if someone here could give me some pointers or tips on when/how to tune in these frequencies, maybe recommend a good antenna, I'd really appreciate it.

    Tory W.
  20. N1NKM

    N1NKM Ham Member QRZ Page

    The vast majority of activity in the VLF range is CW. There may also be some slow-speed, narrow-band RTTY or PSK type signals, but certainly no voice comms.
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