Signal-to-noise ratio based scores

These ratios are calculated between the 95th percentile of power levels across the whole spectrum (signal), and the median power level (noise).

If you are a KiwiSDR owner trying to improve your setup, here are a number of leads from WA2ZKD:

• Have a reasonably good antenna and keep it away from known RFI sources
• Be conscious of things like MW BC overload and apply filters as required
• Avoid switching PSUs, some are quiet but most are not so try to use linear PSUs
• Understand Common Mode Interference, read up on it, apply the easy remedies like use of ferrite core and intermediate grounding on your feedline
• Watch for spurious using the [SPEC] display on a KiwiSDR client webpage, much noise can be noted by "lumps" of noise or spurs carriers at repeating spacing across a band
• ID noise spurious by turning things on/off within your dwelling or near the antenna

The Auto Scale button on the waterfall control tab will also give you instant, real-time signal and noise level metrics - as the WF max and WF min numbers - similar to these scores to evaluate the performance and impact of your improvements as you work on your receiver. "Internal" scores are computed and self-reported by KiwiSDR receivers themselves; you can access those statistics at http://<your_kiwi>:8073/snr You can also use the microkiwi_waterfall.py utility of the KiwiClient command-line suite to replicate external calculations of such scores by yourself. If you know of, or can contribute, a more comprehensive and in-depth guide to improving and getting the maximum out of your KiwiSDR, contact us and we'll gladly link it from here.

Disclaimer: shortwave reception is a complicated topic, and reducing it to a single number comes with no guarantee of getting a representative or useful result! The scores listed here are most relevant when comparing receivers located in the same area.

Note: Internal (self-reported) scores also vary throughout the day, and are usually higher during nighttime.

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