SNR - Signal to Noise Ratio

Signal-to-noise ratio (SNR) is defined as the power ratio between a signal and background noise.

It is normally measured in decibels (dB).

dB value	Description
< 6dB	Poor. No sync, or intermittent sync problems.
7dB - 10dB	Fair. Vulnerable to conditions.
11dB-20dB	Good.
20dB-28dB	Very good.
29dB <	Excellent.