Might I suggest you make yourself one of these:
You can find the files necessary to build it in this thread:
http://www.subsim.com/radioroom/showthread.php?t=114351
You can find an *EXCELLENT* set of instructions, with examples, in this thread:
http://www.subsim.com/radioroom/showthread.php?t=126824
I swear by my angriffscheibe.