KiwiSDR Calibrated Noise Charts

On 2 of my 3 KiwiSDRs I have been running the wsprdaemon script to decode WSPR 24/7 on 14 bands from 2200-10m. The latest release (2.5a) is able to perform a receiver noise reading while collecting the 2 minute WSPR signal sample.

It produces calibrated noise charts for each band with the parameters of noise level in dBm in 1Hz and Temperature in K. Example below:


As far as the interpretation of the graphs is concerned, it’s a learning curve. Diurnal background noise level changes are a good sign for an effective receiving system. I noted on a previous post that I thought that my 30m WSPR reception was affected by vDSL – a look at the 30m chart shows no diurnal variation and has the highest dBm figure.

There is a website which has some other receivers results online, and this will prove very useful when more are added:

2 Replies to “KiwiSDR Calibrated Noise Charts”

  1. I use your WSPR results as a benchmark for the UK, I expect to get nearly the same results except a couple of bands, one where you have local QRM, and those where I do.
    If my results look slow then I check to see if you are in the normal range, if you are slow too I get on with something else.
    I recently tried adding a CB antenna (solaracon 99) to improve my higher HF results and it worked to some extent (17-10m) but adds back in the electrical field noise I struggle with (Big peak at 25Mhz). Swapped it for newer (Gainmaster) and that is useless except on 10m, even stronger 25MHz noise.

    If you could suppress that 30m noise issue I think it would make a big difference as the rest is very lively.
    I did consider trying a phased noise reduction filter here as my main sources of QRM are from the same two locations so should be able to tune for source and frequency of most benefit, not sure how wide the noise affect would be (mainly could it cover two bands like 21&24MHz).
    I have an older Wellbrook loop but here the extra gain just highlights the serious mains born noise. The current active antenna I have tried running under voltage and that seems to help or at least not be detrimental, lowest voltage on paper is 12V at the antenna, I was running at 9.5V at the feedpoint for a few days then 11.1V until this morning when I’ve gone to 12.1V at the feed.
    The noise plots have helped as I can see when a setting flatlines, before it was mainly comparing waterfalls or results.
    Never thought I’d get so interested in subject line WSPR but then I have given up on HF so many times due to QRM never thought I’d bother with HAM at all.

    1. Stu,

      Thank you for your very interesting and welcome comments. I’m currently on holiday so I will give a full response when I return as I wish to discuss the various issues you have raised in more depth.

      73 Geoff

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