jks

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jks
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  • GPS: Galileo reception possible on Kiwi? [working as of v1.178]

    jksjks
    The recent addition of the QZSS sats (Asia/Oceania reception only) increases the percentage of time enough sats are available for fixes (minimum 4 sats required). This is especially true for GPS antennas that don't have a full view of the sky (i.e. shadowed by terrain or buildings). It certainly made a big difference at my NZ location. Since the Galileo E1 signal transmits on a frequency compatible with the Kiwi the question has been asked if it can also be received. It has worldwide reception and so would be very helpful.

    I think the majority of Kiwi owners struggle just to get the supplied antenna near a window, let alone outside and up high. Anything we can do to increase the percentage of Kiwis with functioning GPS would be very useful (e.g. more candidate Kiwis to participate in direction finding experiments). Plus they benefit from automatic, accurate frequency calibration of the SDR.

    I don't know much about HF-DF / triangulation, but fortunately we have a Kiwi user that does. He's already got it working! See: http://hcab14.blogspot.com

    KA7U

  • DDC on FPGA

    jksjks
    Hi. That is an excellent question.

    If you look carefully at the free version of the DUC/DDC compiler provided with Vivado you'll see that it is not general purpose. It is targeted to the cell phone industry (LTE/CDMA) and does not have the bit widths, clock rates and decimation factors needed by the Kiwi.

    The Kiwi does take advantage of some Vivado IP blocks, like the DDS compiler. And it makes very heavy use of the Artix DSP blocks to save FPGA fabric gates. We also wanted to have a design fully independent of any FPGA manufacturer's architecture in case we need to change devices in the future. It was also a learning experience for us to implement everything from first principles.

    KA7Utrain04

  • DDC on FPGA

    jksjks
    Hi. That is an excellent question.

    If you look carefully at the free version of the DUC/DDC compiler provided with Vivado you'll see that it is not general purpose. It is targeted to the cell phone industry (LTE/CDMA) and does not have the bit widths, clock rates and decimation factors needed by the Kiwi.

    The Kiwi does take advantage of some Vivado IP blocks, like the DDS compiler. And it makes very heavy use of the Artix DSP blocks to save FPGA fabric gates. We also wanted to have a design fully independent of any FPGA manufacturer's architecture in case we need to change devices in the future. It was also a learning experience for us to implement everything from first principles.

    KA7Utrain04

  • QZSS Support [GPS, added in v1.170]

    jksjks
    v1.172 adds a switch to the admin page GPS tab called "include alerted?" that overrides the exclusion of alerted sats from the position fix. The alert "A" symbol will appear green instead of red when the sat is actually being used. It will be interesting to see if some position fixes get worse when alerted sats are included.

    fractional_n

  • QZSS Support [GPS, added in v1.170]

    jksjks
    I have recently moved to a new location where I have a limited view of the sky. Either blocked by other apartment buildings or a nearby (hopefully inactive) volcanic cone. The addition of the QZ sats really improves the amount of time I have enough sats in view (4) to compute location fixes.

    WA2ZKDfractional_n

  • QZSS Support [GPS, added in v1.170]

    jksjks
    I have recently moved to a new location where I have a limited view of the sky. Either blocked by other apartment buildings or a nearby (hopefully inactive) volcanic cone. The addition of the QZ sats really improves the amount of time I have enough sats in view (4) to compute location fixes.

    WA2ZKDfractional_n

  • QZSS Support [GPS, added in v1.170]

    jksjks
    Looks like PRN199 is being acquired now.

    fractional_n

  • QZSS Support [GPS, added in v1.170]

    jksjks
    Okay, v1.170 is released with support for QZSS.

    fractional_n

  • QZSS Support [GPS, added in v1.170]

    jksjks
    Well, that was easier than I thought.

    I'm tracking PRN 194 and 195 no problem from here in New Zealand (QZS-2 and -4 respectively). Subframes are decoding and the software is flagging them as good. I have a little work to do to make the az/el display work correctly for them.

    WA2ZKD

  • New category: Installation, Antennas and Interference

    jksjks
    I've added a new category specifically for installation, antenna and interference topics. There were some older, but very valuable, discussions in the general "KiwiSDR Discussion" category that were difficult to find due to the sheer number of topics in that category. If there are others you think deserve to be moved please let me know (i've only looked back about six months so far).

    f1jek