VEMCO – VR4-UWM Manual
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3.4
Unique to Acoustic Modem communication
3.4.1
Automatic tuning
When modem communication is established between the surface modem and the VR4-UWM, the lower half
of the screen shows the status of the communication. The VUE software will adjust the bit rate and ranging
period as needed to give optimum communication given existing conditions. The slider allows you to tell
VUE if you prefer the focus to be on reliable communication (move the slider to the left) or on retrieving the
data as quickly as possible (move the slider to the right).
The Success Rate will show one of the following results based on the rate of successful communication: Very
Poor, Poor, OK, Good, or Very Good. Poor ratings are caused by repeated errors encountered when
transmitting the data from the VR4-UWM to the surface. These errors also require the data to be re-
transmitted. To improve the rating, move the slider closer to the “Reliable” side of the scale. If the success
rate does not improve, then use Advanced Tuning (see section 3.4.3).
Only the bit rate is adjusted automatically. Use the Advanced tuning option
(section 3.4.2) if the power settings need to be adjusted, such as increasing
the power to compensate for an increased distance from the receiver or to
decrease the power to lessen the echoes produced in an acoustically
reflective area.
3.4.2
Advanced tuning
By default the VUE software has the modem tuning set to Automatic Tuning,
but there are times when it’s more desirable to select these settings yourself. To
take the modem communication settings off automatic, click the Advanced box
in the Automatic Tuning section of the window and make the desired
adjustments. This should be done with caution as the modem settings will not
automatically adjust for peak communication and could negatively affect
communication.
If you are unfamiliar with the settings necessary at a particular location, begin
with the settings shown in the sample shown at right and make further
adjustments as needed. These settings are a good starting point.
When to make adjustments, and what adjustments to make, depends on the unique conditions at the location
and time of communication. Some important points are listed below.
Automatic Tuning only
varies the bit rate. The
acoustic power level must
be changed manually.