B&G H2000 Pilot *DISCONTINUED* - Manual (Page 153)

HB-0844-04
6-11
(c) Following or crossing the path of another vessel which has left
an aerated layer in the water.
6.3.4 Random Deep Depths
Symptom: Display shows random deep depths.
Possible Causes:
(a) Electrical noise. The depth sounder contains circuits and
software to reduce its susceptibility to electrical noise, however this
can still be a problem if not installed carefully or other equipment is
not correctly suppressed. The depth sounder measures the ambient
noise and this can be found for display by looking under the
PARAMTR Menu. When the boat is stationary electrical equipment
should be switched ON and OFF in turn while looking at the depth
and noise displays to try and determine the source of the problem.
(b) Acoustic Interference. Other depth sounders and sonar can
cause problems. However this is generally only when very close to
other boats for example when moored alongside in a crowded
marina. Also acoustic noise can be generated by water flow past the
transducer and various bits of mechanical machinery.
(c) Mid-water echoes. When outside the range of the depth
sounder it is possible that random depths are displayed due to mid-
water echoes from shoals of fish or aeration layers.