VEMCO – VR100 Receiver Operating Manual – Page 12
2.2.5 Manually tracking a coded tag
After a channel in the VR100 has been setup to detect the coded pinger (see section 4.3.1.2.2) and the
pinger has been deployed, use the steps below to use the VR100 to track the pinger.
Tracking a tagged marine animal requires a directional hydrophone. The VR100 receiver is compatible
with the VH110 directional hydrophone. The directional hydrophone must be mounted on the end of a pole
so it can be rotated. It’s also helpful to mark which section of pole is facing in the same direction as the
black section of the hydrophone. This black section is the signal sensitive section of the hydrophone.
Tracking a coded tag is more difficult than tracking a continuous tag because coded tags transmit in ping
trains. A ping train is a burst of pings lasting 2-3 seconds followed with a delay that can be more than a
minute long (the delay length is determined by the customer at the time the tag is ordered). There is often
more than one tag in an area so you must determine which tag you’re tracking based on its ID number.
From the Main menu:
1.
Select Monitor by pressing the left selection button. A screen on the VR100 will appear similar to the
sample below.
2.
Press the channel number on the keypad to select the channel to be monitored.
3.
Use the left selection button to select the desired level of Detection Parameter (sere section 4.2). The
sample below has been set to Norm.
4.
Verify that the frequency shown is the desired
frequency. If it isn’t, then the channel setup must be
edited (see section 4.3.1.2).
5.
Deploy the omni-directional VH165 hydrophone
and listen for coded tags in the area. Make note of
the code numbers and code spaces that are identified
and displayed in the second and third lines on the
screen. In the adjacent sample screen, the tag with
codespace A69-1303 and ID number 154 was
identified.
6.
Remove the omni-directional hydrophone from the water and deploy the directional hydrophone.
7.
Use the audio output from either the speaker or the headphones to listen for the deployed pinger.
8.
Ensure the receiver is in manual gain mode and adjust the gain so that the pings are strong but not
saturating the receiver. Use the signal strength meter as a guide (signal strength varies from 0 to 105
dB).
9.
The length of time since the last ping was received is shown in the top left corner. If the length of time
is very large, the display will show 999 to indicate there haven’t been any recent detections.
10.
Slowly rotate the hydrophone rod in one direction. If the signal gets louder and stronger (the signal
strength level and bar graph increase) then continue to rotate the hydrophone in that direction. If the
signal gets softer and decreases, then reverse the rotation. When the signal is its strongest, the
hydrophone is pointing in the direction of the tag.
11.
Move in the direction the hydrophone is pointing and watch/listen to the signal strength. If the signal
strength decreases, repeat step 11 until it increases again.
12.
If necessary, adjust the gain so that the pings are strong but not saturating the receiver.
13.
Continue this process of following the signal strength and adjusting the gain until the signal strength is
strong in all directions (rotating the hydrophone doesn’t change the signal strength). The tag is below
the hydrophone.
LT: 26
09:32:01
A69-1303
35dB ▊▊▏
# 154
Norm CH1
M18 Mute
