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la3rk

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la3rk
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  • Wideband noise around 1.6 MHz

    At least one source identified and reduced. My station pc is powered via the 12 volt supply. Even when off it supplies 5v via usb. The internal voltage controller sent significant noise back on the 12 v bus and was picked up by the outside antenna. Probably following the coax outside, my choke was not sufficiently effective below 2 mhz.

    Found by sniffing with a ferrite rod antenna while watching the spectrogram.

    There is also some noise on my mains ground, my mains filter had a straight through earth wire.

    My SNR ratio is improving, now seeing numbers around 25 dB (P90 level minus mean level, 0 to 30 MHz)

    73 de Olaf - LA3RK

    Powernumptycathalferris
  • Wideband noise around 1.6 MHz

    Basically a rewrite from microkiwi_waterfall.py in github, https://github.com/jks-prv/kiwiclient Microkiwi_waterfall.py gives you some statistics on a given frequency band. Data from this program is combined with a socalled round robin database/graphing tool, some crontabs and a minimal web page. Needs some python knowledge and local adjustments.

    Free for anyone to use, but I need to find a location to share the code. Current version attached, but you need to collect utilities from kiwiclient link above. Had to include as txt file, py extension not allowed.

    Python 3 recent version needed. Program is runnung on a local raspberry. I do not think such program should be used on a remote kiwi without owner accept.

    As to the variation in noise level approx every 30 min,, it seems to be connected to a Samsung freezer, noise coincides with run times on freezer. Change of levels betwwen day/night is propagation (peak levels) and less human activity night time, less overall noise.


    73 de Olaf - LA3RK


    Powernumpty