Narrowband Contacts

[vinny2005]

Hi from time to time i get narrowband contacts which sometimes can be very close and the spike can be big and its sometimes making a racket but theres no i.d to it on NB yet the line on BB is thick and making a lot of noise.

And also sometimes i cant assign trackers to contacts on the NB.

[LuftWolf]

The contacts with no NB signature are most likely biological, like shrimp or whales. Listen to the BB and you can tell from there.

In terms of not being able to assign a tracker to a contact in NB, make sure you have not only put the cursor on the right bearing, but also clicked on a distinct frequency line on the display, since NB trackers are assigned to a particular frequency.

[drEaPer]

If I have 2 trackers on, say, 500hz; one at 350° moving clockwise, one at 10° moving counterclockwise, will the sonar tracker get confused when both contacts pass each other, since they overlap and the trackers are both tracking that specific frequency? Could it be possible that the trackers get mixed up? (RL/Game)

Never thought about that before, but the question just jumped into mind when reading this thread.

[sonar732]

If I have 2 trackers on, say, 500hz; one at 350° moving clockwise, one at 10° moving counterclockwise, will the sonar tracker get confused when both contacts pass each other, since they overlap and the trackers are both tracking that specific frequency? Could it be possible that the trackers get mixed up? (RL/Game)

Never thought about that before, but the question just jumped into mind when reading this thread.

That depends on the bearing rate. If it's high, the trackers won't get confused...if it's low, then as a former sonar operator, we had to pay close attention to the different contacts to make sure that one of them didn't change course.

[drEaPer]

I guess in DW this isnt modelled, right?