jks

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jks
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  • Help diagnosing interference issues

    jksjks
    Okay, first of all my apologies for not understanding the sophistication of your setup. It is absolutely excellent. Hopefully my long-winded explanation above will help someone else because you clearly understand the issues.

    Now the problem: You've got the worst case of a bad switching power supply I have ever seen. The first clear carrier is on 167.9 kHz @ -66 dBm and appears about every 30.5 kHz up to 30 MHz. The carrier is narrow and stable but has "static" mixed in. This is a classic trait I've seen many times. The UVic beta site had a horrible signal like this around 14 kHz. Fortunately the harmonics died out in the LF spectrum. After almost a year it was traced to a bad power supply in an Ethernet switch.

    The fact that the harmonics go to 30 MHz and are so loud makes me wonder if it's a problem with one of the switchers on the Beagle. Like a bad filtering cap or something. The overall 0-30 MHz spectrum looks similar to the high noise problems we had with an early Element 14 manufactured Beagle. I assume this is a BeagleBone Green? I'd be happy to send you a replacement.

    There is also another huge signal (-56 dBm) at 86.5 kHz that is about 2 kHz wide and has the classic look of a "spread spectrum" (flattop) clock. It has harmonics in the NDB band every 9.5 kHz but dies out at MF.

    KM4YRI

  • Help! display partly dead.

    jksjks
    v1.28, and a few releases afterwards, were completely FUBAR unfortunately.

    g1tvl

  • kiwi.bin fails on PMUX check

    jksjks
    In case anyone is interested I'll explain: For various reasons a user program (one with privileges) cannot directly change the pin mux (PMUX) that determines which device functions and attributes are assigned to the I/O pins of the Sitara processor used on the Beagle. This is specified by device (cape) overlay files used by the kernel and by some other mechanisms. So there is some checking code to make sure the pins are in the state the Kiwi server expects. The panic you saw occurred when one of the unused expansion pins on the P8 connector was detected to have been set as an input with a pull-up rather than a plain input with no pull-up or pull-down. More pins were in unexpected states as shown in the file you attached.

    Now this by itself is not a problem. But the real question is why is this different all of a sudden when there are hundreds of other units out there running without an issue? This is one of the reasons why the Kiwi is shipped with a fixed, known-working Debian distribution. To try and eliminate the side-effects of dependancies like these.


    KA7U

  • Do you want a Facebook Page for KiwiSDR?

    jksjks
    "A" on 2097 is one of HF pirate beacons. Some of the best info is on HF Underground: https://www.hfunderground.com/board/index.php/topic,9478.0.html

    For a discussion of military "letter/marker beacons", some of which are in the Kiwi dx list, see here: https://en.wikipedia.org/wiki/Letter_beacon

    I personally boycott Facebook, but you guys can obviously do what you want. But I won't be contributing there if you do.
    At some point we'll need subcategories for the Kiwi discussions here.

    PA0PJE

  • Is there any gain control?

    jksjks
    Hi Neil,

    If you press the "more" button on the lower right control panel you'll see various AGC parameters that can be adjusted. Changing the Threshold and Slope will effect the gain. There is also a Manual Gain slider that becomes active if you turn the AGC off.

    There is the volume control of course. There is no hardware gain control in the RF front-end. This was a cost tradeoff. 

    MA3101SWL