ok doing some semi scientific testing with 1 crash site, and 1 nut tree(or bush?) both in walking distance of my main base..
I found that I can detect the Nut from 29+ foundations away.. with single beep becoming faster beeps as I get closer to said nut..
However.. the Crash-sites.. the detector does not even go off past 12 foundations (though it does beep at 11 possibly..
I feel that players should be able to detect crash sites further away then 12 foundations.. cause at 12 foundations or less your probably being attacked by enemies that guard it anyway - or that seems to have been my experience when out exploring for crash sites for HDDs.
I also think it should only detect when crash-site has HDD still - figure if we have found it and opened it, we would have disabled its emergency beacon/locator so as not to confuse it with other sites..