KiwiSDR TDoA, (Time Difference of Arrival), is now a reality

Discussion in 'Ham Radio Discussions' started by NK7Z, Jul 12, 2018 at 1:00 AM.

ad: L-HROutlet
ad: l-rl
ad: l-BCInc
ad: l-assoc
ad: L-MFJ
ad: Subscribe
  1. K5URU

    K5URU XML Subscriber QRZ Page

    I played around with the KiwiSDR TDoA extension for a few hours last night and wrote up some notes in the other thread about the time pips (link). It's really neat, and I can't wait to see all the cool things people do with it.
     
    W1TRY likes this.
  2. K5URU

    K5URU XML Subscriber QRZ Page

    Well, I'm impressed already. Here's a basic example of how it works. See the link in the OP for full instructions.

    Choose your target frequency, Select a few KiwiSDR stations from the TDoA map, and click the "Submit" button.

    Here's the KiwiSDR webpage, with the TDoA window on the bottom left and the map above:
    6030_Kiwi.PNG

    Target: 6030 kHz AM broadcast.
    KiwiSDR receivers selected:
    W1EUJ in Concord, MA
    W5 station near Lubbock, TX
    W1NEJ in Boca Raton, FL​

    Raw KiwiSDR TDoA result:
    6030_A.png

    Here's the same result after I added a Google Maps background and marked the actual transmitter location:
    6030_composite.png

    The transmitter in this case is VOA Site B in Greenville, NC. [Google Maps link]

    As you can see, the KiwiSDR system was very close on the first attempt, even with only three distant receivers selected. Once you know the general location, you can choose closer receivers to get even more accurate results. Very cool!
     
  3. N3HGB

    N3HGB Ham Member QRZ Page

    This is LORAN in reverse. LORAN is where you know where the transmitter is, this is where you know where you are.
     
  4. W5INC

    W5INC Ham Member QRZ Page

    HF radio directional location systems have been in use before WW I. The Germans developed the Wullenweaver station in the early 1940s. The Soviets then took the lead in the years directly after WW II and the USA/NATO got caught up in the late 50s. Wullenweber antenna systems were all over the Globe at 1 time and a few are still in use today. These outposts could pinpoint a hostile sub very quickly, which was it's main job. Pusher CDAA systems are now used for HF directional finding tasks and these units can find a needle in a haystack so to speak.
     
  5. W2NAP

    W2NAP Ham Member QRZ Page

    looks like someone already did. check the time pip thread. looks again like the Chicago area
     
  6. KQ9J

    KQ9J Premium Subscriber QRZ Page

    I'd be happy to buy one and set up a dedicated antenna to become part of this system, if I knew that finding jammers and DQRM'ers would result in some enforcement action.

    Or at least some broken fingers :D
     
    ND6M likes this.
  7. KY5U

    KY5U Subscriber QRZ Page

    Let's ask @N2EY, he was there!
     
  8. N3HGB

    N3HGB Ham Member QRZ Page

    VERY COOL IDEA!
    OTOH I tried 4 times to locate WWV and failed :(
    I got some good lines, but either they never crossed and/or I only got one per try. This didn't exactly cost me any money, so no complaints. I'll try again after lunch.
     
  9. WZ7U

    WZ7U Subscriber QRZ Page

    The point being now it is available to the layman. At your convenience. That is the big wow behind it, not the actual tech IMO.
     
  10. K3DCW

    K3DCW QRZ Lifetime Member #212 Life Member Platinum Subscriber QRZ Page

    There are some issues with TDOA on HF beyond ground wave: issues which can induce rather significant errors, but I agree that this is a "big wow" for the layman.
     
    WD4IGX likes this.

Share This Page