Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx
Page 16
4.8
Signal Spread
This can be used to determine the amount of “turbulence” affecting the signal quality and
used to reject the measurement if the spread (turbulence) is too great. A good flow would
return a spread value of around 50; anything above 100 would be considered poor.
Spread Channel Interpretation:
0-50
Excellent SPREAD
60-200 Average
SPREAD
200-500 Poor
SPREAD
Above 500 Above 500 gives unreliable velocity data.
4.9
Received Signal Strength Indicator (RSSI)
The RSSI channel is the measurement of the received signal power. RSSI values may
change significantly for each measurement because of the number of reflectors in the water
at any given time.
In turbulent water, the reflectors are more likely to be in suspension, resulting in higher
signal/RSSI values. Subsequently, the smoother flowing water “may” have fewer reflectors
and lower signal/RSSI values. However, signal/RSSI values are dependent, not only on the
turbulence but on fluid velocity as well.
RSSI Channel Interpretation:
0
No
Signal
3-200 Typical signal in water
>1000
Not usable Signal (Too Noisy)
