GNSS Carrier-to-Noise density (C/No) color scales are somewhat arbitrary. What's considered a pass or fail would depend on the GNSS receiver, application requirements and the surroundings. At VeEX we try to provide the most generic scale possible.
Carrier-to-Noise density (C/No) color scales are somewhat arbitrary, as their significant levels may depend on the capabilities of the final GNSS receivers to be connected to the antenna under test. Some devices may consider 21 dB-Hz "Good" quality, while for others that same qualitative level may be at 28 dB-Hz. Sometimes the default "C/No Mask" setting can give you an idea of the minimum signal quality recommended by the manufacturer for a specific GNSS receiver. Network equipment manufacturers (NEM), test and measurement and monitoring/assurance vendors who have adopted the sky view functionality, use different color palettes and grading ranges, so direct comparisons would require full understanding of their specific scales.
The SkyView™ GNSS Antenna Reception Quality Pattern heat map (polar graph on the test set) uses a linear color scale to map C/No density levels for better differentiation on the screen. This helps in identifying and troubleshooting weak spots.
On the other hand, our SkyView report template (for Microsoft™ Excel), uses a simplified color scale that focuses on perceived quality levels. It maps RF signal reception quality into six distinctive and intuitive levels (ranges), for better contrast.
45 to 52+ dB-Hz, Excellent- 36 to 44 dB-Hz, Good
- 27 to 35 dB-Hz, Fair
- 18 to 26 dB-Hz, Marginal
- 9 to 17 dB-Hz, Poor
- 1 to 8 dB-Hz, Bad
Experienced Excel users can modify the ranges to better match the specific requirements for their equipment and/or applications. For example, one could create a modified report template for indoor antenna applications. However, it is recommended to maintain a common scale for all applications and just know how to translate the individual colors to their signal quality range. The color scales are always visible on the screen and in the Excel Report Template.
What passes inspection and what fails, would depend on the equipment, application requirements and the surrounding environment. Roof antennas are expected to be from yellow (towards the horizon, <20º) to full green towards the zenith (90º), while indoors antennas (with decent reception) should usually be in the range from orange to yellow.
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For more information about SkyView, visit our Knowledge Base page.