jks

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jks
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  • v1.79 Reboots

    Okay, I think I see something wrong now..

    WA2ZKD
  • Worried about time?

    [humor, sarcasm]

    Sure, but be careful. For some people this is a slippery slope into full-blown "time nuttery", e.g. Time-Nuts, LeapSecond.com. Believe me, I know. It starts with PPS-producing GPS modules. But then quickly escalates into buying a GPSDO and/or surplus rubidium OCXODO from that Ebay guy in China. All of a sudden you're building your own GPSDO. Then acquiring an old hp 5370A/B TI counter, or two, or three or ten. Perhaps even adding my CPU upgrade. Then you score your first cesium standard off Ebay. You might even get one with a semi-working beam tube. Pretty soon the Allen deviation/variation plots are flowing and three-corner hat comparisons being made. This list is maybe 2% of what's likely to happen.

    Now things really fall apart. You decide you need a hydrogen maser. So the sports car and/or summer home get sold to raise the cash required..

    Absolutely no cure, except to get distracted by something equally interesting/addictive.


    WA2ZKD
  • KiwiSDR Clock Lags?

    One thing I could do I suppose is have the Kiwi server occasionally check for NTPd running and restart it if necessary.

    Something like that always sounds simple. But when it comes to implementation there are always funny edge cases to consider and the possibility I'll release a version that bricks everyone's Kiwi. I've been lucky about that so far..
    WA2ZKD
  • Using BB Black wireless or BB Green wireless board

    Yes, a WiFi dongle on the end of a USB cable with some type 77 and/or 43 toroid cores as a common mode choke is a great idea. Be sure to use a 5V power supply of at least 2A. The Beagle manual warns about the increased current requirements when using WiFi dongles.

    A long Ethernet cable shouldn't be a problem (the spec is 100m max). Just use toroids as above at the Beagle end. Because Ethernet uses differential signaling it isn't much of a problem except for the EMI from elsewhere that rides down the cable common mode. Be sure not to use shielded Ethernet cable as this may cause a big ground loop depending on your equipment grounding.

    ajwhall
  • Using BB Black wireless or BB Green wireless board

    Hi Andrew,

    I need to add a FAQ about Kiwi WiFi connections. Let me tell you what I know.

    It has been successfully done with a USB dongle by Yuri at http://msk.swl.su:8073 (see his top bar photo). He runs a loop and the noise floor is clean. So there is no problem with HF interference from the dongle. There are software issues though. The Kiwi works, but doesn't display the local ip address properly, etc. I need to fix this.

    The BBG wireless (BBGW) is not physically compatible with Beagle capes due to how Seeed placed the USB-A connectors, i.e. you can't plug in a Kiwi board without it hitting the USB connectors. Now you could use some Beagle header extenders to build-up the header stack to get clearance. But I have not tried this yet. The electrical implications are unknown. And such a stack would obviously not fit in the plastic case. To see this problem look at an end-on photo of the BBGW at the Seeed site: https://www.seeedstudio.com/SeeedStudio-BeagleBone-Green-Wireless-p-2650.html

    The BeagleBone Black wireless (BBBW), which was recently introduced, is cape physically compatible. But I have not tried this one either.

    A while ago I ran an experiment where I brought a running BBGW close to a running Kiwi and noticed the HF noise floor rise. So that worried me. Note that the WiFI chip and output coaxes and antennas of the BBGW is at the end of the Beagle PCB nearest the Kiwi HF/GPS front-ends. Whereas the BBBW and use of a WiFi dongle on a BBB are at the other (safer) end where the power connection is.

    ajwhall