[Pisces]

The hydrophone only has a maximum range of 34km (if you listen yourself). That is still a needle-head in the proverbial Atlantic haystack. It won't help you much if you don't know where to be looking for them.

The contact report icons of single units and convoys are only shown when they are in your immediate surroundings. I think it is some 250km by default. You can find these range settings in the file:

SilentHunterIII_installfolder\Data\Cfg\contacts.cf g

It is just a text file that you can open with notepad (Windows) or whatever equivalent simple text editor the Mac has. They are the first two lines. I don't know what the difference is between Opportunity and Important Radio contacts. But I feel there is no realism objection for increasing these ranges substantially. Radio operators of Uboats should have been able to receive messages from BdU at distances a lot more than that. It doesn't create more convoys or other contacts in the world. (That is all up to the campaign scenario files) But if they are there, and the campaign files feels you are lucky enough to deserve an icon to be given (based on random number generator, probability setting and time interval), you should see them further out on the map. And it will be up to you if they are worth it to go after them.