LOU has covered the NDB/ADF useage in the Captain Sim aircraft well. I would only add the following regarding the expected range. It appears to me that the default setting in FSX is for between 20 and 50 nm which are low powered NDB's. So if your not getting it think about not using it or expecting to get a signal indication until you are within about 40 nm unless it is a locator beacon where were only good for 10-20 nm.

For many years the NDB was the radio navigation aid standard and in some countries the only available radio aid and some were very high powered indeed and the ranges exceptional, for example, in Australia where I used to fly maritime patrol aircraft the Sydney NDB could be picked up at 400 nm and similalry for the Perth NDB, Townsville was also very good and good be picked up at several hundred miles. The NDB approach was until very recently mandatory here in OZ for any Instrument Rating Renewal no matter if you never really used it, so you got to know them and their idisosynchrasies very well. And if your really wanted a flying and cockpit dexterity challenge try a twin locator approach quite a few of which still exist here in OZ (like at Darwin) and around the world,