Vemco VR100 - Page 65

VEMCO – VR100 Manual 28 May 2018 59
Mute Audio
The audio heard from either the speaker or headphones is muted by pressing the right selection button
below the word “Mute” in the Monitor screen. When the Mute button is pressed, the audio is muted and
the word “Mute” briefly becomes “VOL00” to indicate that the volume is zero. The volume is restored at
the same level by pressing the Mute button again. The volume can be restored at a level above or below
the muted volume level by pressing the volume buttons on the front panel (see section 1.5.4).
When the volume level is changed, the “Mute” will change to “VOLXX” for a moment to indicate the
volume level. The XX in “VOLXX” is a numeric representation of the volume level.
Gain level
The number shown indicates the amount of gain the receiver is using, in decibels (dB). The gain can be
manually increased or decreased using the Gain buttons on the front panel (see section 1.5.4). The gain
moves in steps of 6 dB (decibels) and can be changed either manually or automatically. An “M” next to
the gain number indicates the gain is in manual mode while an “A” indicates it’s in automatic mode
(AGC – Automatic Gain Control). The mode is toggled between automatic and manual by pressing the
AGC button on the front panel of the receiver (see section 1.5.4).
NOTE: Since the VR100 receiver has a wide dynamic range, the gain setting is not critical in most
situations. A good setting for general use is to set the gain manually to 12 dB. If the reported signal
strength is consistently greater than 90 dB, reduce the manual gain setting. When working at extended
ranges or if the reported signal strength is consistently weak, increase manual gain setting. In some
adverse situations where the manual gain control does not provide adequate results, try using the AGC
mode
Channel number
The number next to the “CH” indicates the channel number being monitored. Press the number on the
keypad that corresponds with the channel number to monitor that channel.
Detection Parameter
The detection parameter determines what is identified as a received ping and what is considered
background noise (see section 6.9). The three detection parameter settings available are listed below. A
more detailed explanation is found in section 6.9.
Parameter
Name
Detection Level
When to Use It
Near
Background noise is almost never mistaken
as a real ping (called a false detect), but
some real pings may be mistaken as
background noise and blocked.
Use when the VR100 is receiving too
many echo signals on the Norm
setting, such as when the tags are in
an enclosed area like a tank.
Norm
Not as aggressive as Near and not as liberal
as Far. Most real pings will be detected but
some background noise may be mistaken as
real pings.
Use this level for almost all
applications.
Far
Nothing is blocked. This allows almost all
real pings to be received but background
noise will be mistaken as real pings.
Use when the tags are far from the
hydrophone or the signal is weak. This
could increase the range.