G8JNJ

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Username
G8JNJ
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South West UK
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G8JNJ
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https://g8jnj.net/web-sdrs
  • TDoA Successes

    I'm quite pleased with this one, especially as it's an HF signal and there are not that many suitably placed KiWi's.

    It's a Russian CIS-12 signal on 11175KHz.



    Regards,

    Martin - G8JNJ
    WA2ZKDKA7Ujks
  • Direction Finding and linking existing KiwiSDRs

    Hi John,

    Excellent and very timely :-)

    There is currently a problem with a military FSK signal in the 40m amateur band that folks have been trying to ID. I ran a TDoA on it this morning and was able to narrow down the likely transmitter site fairly accurately (given the number of KiWi's currently listed.

    So a big thanks to all concerned especially John, Christoph, linkz and others who have managed to make this work.

    I don't think I'm overstating it when I say that this is likely to be a real game changer, especially when trying to ID unknown or interfering signals and makes what would previously have been only within the capability of national regulators or the military available to everyone.

    This is truly ground breaking.

    Regards,

    Martin - G8JNJ
    WA2ZKD
  • LZ1AQ LNA and a 1.2 meter copper loop antenna.

    Hi Ron,

    Reducing the loop inductance (for a given size) is something worth trying if you want to improve the performance still further on the HF bands (>10MHz).

    This is less critical when you are using a loop amplifier with a fairly high input impedance, but in the LZ1AQ design it is only in the region of a few ohms (which is great for the LF bands), so loop inductance becomes a critical factor as you go up in frequency.

    You can either make the loop a lot 'fatter' to reduce the inductance, connect several same size loops in parallel (but spaced by a few inches), or cross-connect four or more independent loops together.

    Chavdar has good notes on this subject on his website.

    http://active-antenna.eu/tech-docs/3_ActiveAA_Antena_11.pdf

    Regards,

    Martin - G8JNJ
    KA7U
  • Home Brew Broadband Magnetic Loop

    Hi Ron,

    A couple of weeks ago I received a private email about this circuit, and decided to make a copy, as the person who wrote was having problems with it, and I couldn't figure out how the circuit could perform as described.

    I found that the IMD performance was poor and it had several other issues which couldn't be easily fixed.

    If you want to build or buy an amplifier of this type, my advice would be to take a look at the DXE RPA-1 circuit instead.

    image



    Regards,

    Martin - G8JNJ




    KA7U
  • v1.154 released: New user interface, Navtex extension

    Hi,

    Three other signals I've decoded (so far)

      6322.5 CW FSK 170Hz shift 100bd, Murmansk, Russia
    12603.5 CW FSK SVO, 170Hz shift 100bd, Athens, Greece
    12622.5 CW FSK XSQ, 170Hz shift 100bd, China

    Regards,

    Martin - G8JNJ
    WA2ZKD