VEMCO – VR100 Receiver Operating Manual – Page 32
D)
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
3.1.3).
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.
E)
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 3.1.3). 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 3.1.3).
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
F)
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.
G)
Detection Parameter:
The detection parameter determines what is identified as a received ping and what is considered
background noise (see section 5.3). The three detection parameter settings available are listed in Table
4.2-1. A more detailed explanation is found in section 5.2.
Table 4.2-1: Detection Parameter levels.
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.
