"Eternal" excellent SNR-ranking for some Kiwis?

From time to time, I check my own Kiwi's SNR-ranking. Being a night-owl,

I have the advantage to find my scores between 50 and 15 in the hours

after midnight, Around noon, however, it is mostly a two-digit number.

Finding certain Kiwis always in the top class, disregarding the time of day

and/or night, I wondered how that could be.

--> well some are simply cutting unfavourable ranges, such as the very

low VLF range. Others are "sportsmen" using the slogan "Notch as notch


Of course, every Kiwi-ower is free to "amend" his Kiwi, however, why do

I have the feeling that such an attitude has little to do with "ham spirit"?

Vy 73 de F1VAM


  • Hi,

    if you have a strong broadcasting station nearby you may have the SNR value you like. If you have local non-wideband QRN, you'll have high SNR. If you receive one single decent station on the entire HF bands but you have low noise because your antenna is totally deaf, you'll have high SNR.

    SNR values are entirely flawed, sorry. And no, you cannot fix them. A single 0-30MHz spectrum look to an expert eye gives FAR more information.

    I know that a single number is really appealing to the human mind to classify everything. People like it because it "gamifies" the improvement of the rx: you can sort by "quality", you may reach the top spots, etc.

    What a pity it doesn't work. If you run a correlation between SNR values and a subjective (expert) level of quality, you get almost zero.

    DISCLAIMER: I previously run a website computing SNR for all kiwis every hour.


    marco / IS0KYB

  • Thanks for your comment, Marco.

    Well, the ideal environment is "quiet rural", but even then, there is no "guarantee" that this will stay forever - one PV-system with "QRM-inverter" or even an "optimizer" can suddenly destroy the "paradise".

    Any Kiwi-operator should try and analyse the local trouble makers. Filters can help against strong local BC-stations, but unless the cause coarse intermodulation.

    Wide-band noise sources are more annoying.

    From time to time, I visit other Kiwis checking their displays for QRM patterns that are "famous", such as VDSL, PLC outside the (very helpful) notches, inverters working below 100 kHz et al.

    Yes, many people are "hungry" for simple issues - and solutions.

    As for SNR-tricks: Honesty could help in some cases rather than fraud and "beaming with pride"

    If you like, you can visit www.enams.de to find Thousands of spectrum records from Germany and other countries in and outside Europe. The site is in German, but www.deepl.com can easily remove that "hurdle".

    For any possible questions, you can mail me under vae@email.de

    Vy 73 de F1VAM


  • Thanks Wolfgang,

    I'll visit that website, seems interesting.



  • edited July 2022

    Quite agree with Marco's and Alsace's comments and that it would be possible to game these wideband SNR values intentionally. A site that I found quite interesting is https://rx-tx.info with screen shots of almost all public web SDRs.

    When updated frequently it might be possible to arrive at different quality / snr measures based on such waterfall snapshots using various computer vision techniques. Still it will be a challenge to translate and quantify our visual perception of better and clean waterfalls or spectra into an algorithm.

    Nice AI project me thinks..


  • Yes, Ben, that site is very helpful. One selects a country and quickly finds sites in the vicinity. Moreover, OpenwebRX is included.

    By the way: AI is already being applied in this project - www.enams.de. Terabytes of data are evaluated for a scientifically-based classification of the QRM radio amateurs are exposed to in their bands up to 30 MHz.

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