Welcome to Subsim.
Having just recently switched from 1.4 to 1.5 I think I can help you out.
The sonar ping will work but in my experience you can't be too far away. What I've found is that if the target is at a very long range the active sonar will spin then stop then a short time later you'll hear the return 'pong'. At that point you should hit the 'send data to TDC' button and you'll see the range displayed in your message box.
If the target is well within active sonar range then you'll see the indicator stop before a full revolution and the return 'pong' but, if memory serves, you still have to hit the 'send data to TDC' button before you'll see the range stated in the message box.
One thing to remember: if there are warships about and you're using active sonar then be prepared to get a lot of attention!!!
Hope this helps.
