G4DYA

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G4DYA
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  • HF Emergency broadcast frequencies

    The HFCC (which coordinates HF broadcast assignments) tries to keep one frequency in each HF broadcast band in reserve for emergency use, which they call International Radio for Disaster Relief (IRDR). More here:

    http://www.hfcc.org/humanitarian/

    Powernumpty
  • Kiwi BBAI software Alpha test instructions [updated 3-Jun-21]

    I'm attempting to provide cooling for a BBAI in a Seeed case. Without the end plates, two 5V 25mm fans side-by-side works well.

    First, I installed the AI but didn't use star washers next to the board - components are too close for comfort. Instead I used two star washers between the standoffs and the case. I didn't use the nylon standoff at all because there's a chip capacitor very close to the hole.

    image

    Next I stuck two fans to the Kiwi board and connected them to the bottom of the 5v barrel jack. I added a bit of draught excluder to the side of one fan.

    image

    Then connected the Kiwi to the AI.

    image

    Then stuck the lid on. Without anything at the end I held it together with Gaffa tape!

    image

    This arrangement keeps the CPU temperature well below 50° C. With the end plates on, it obstructs the airflow quite badly and is noisy. Next step is to try some sort of mesh grille. After that, I might try some sort of conduction cooling with chunky slabs of copper inside and heatsinks outside.

    73,
    Richard G4DYA
    HB9TMCPowernumptyrz3dvp
  • Kiwi BBAI software Alpha test instructions [updated 3-Jun-21]

    I'm attempting to provide cooling for a BBAI in a Seeed case. Without the end plates, two 5V 25mm fans side-by-side works well.

    First, I installed the AI but didn't use star washers next to the board - components are too close for comfort. Instead I used two star washers between the standoffs and the case. I didn't use the nylon standoff at all because there's a chip capacitor very close to the hole.

    image

    Next I stuck two fans to the Kiwi board and connected them to the bottom of the 5v barrel jack. I added a bit of draught excluder to the side of one fan.

    image

    Then connected the Kiwi to the AI.

    image

    Then stuck the lid on. Without anything at the end I held it together with Gaffa tape!

    image

    This arrangement keeps the CPU temperature well below 50° C. With the end plates on, it obstructs the airflow quite badly and is noisy. Next step is to try some sort of mesh grille. After that, I might try some sort of conduction cooling with chunky slabs of copper inside and heatsinks outside.

    73,
    Richard G4DYA
    HB9TMCPowernumptyrz3dvp
  • GPS antenna alternatives

    Just to add to this dormant thread, yesterday I installed a PCTEL GPS-TMG-40N antenna with low-loss feeder and it certainly does the trick. I went for the 40 dB version so there's plenty of signal in hand to feed a 4-way passive splitter when I get one. I'm somewhat screened by tall trees in the south-west quadrant, so don't get many low-elevation signals from there.

    The KiwiSDR GPS software only seems to allow a maximum of four Galileo satellites in the 12 channels. Is this intentional? While it all works fine, it would be nice if the limit could be raised - either by allowing more than four Galileo sats, or by allowing more than 12 channels. Also, surely there isn't much point in scanning for QRZZ satellites in Region 1?

    WA2ZKDPowernumpty