Of course, YMMV since every environment is different - but these are some longer distance examples we have - 21 KM to the furthest, which is about 13 miles with still an MCS12 performance.... and that one has got some trees right around their yard, but fairly clear the rest of the way.
BUT - examples at:
7.07 KM = 4.4 miles = MCS 14/14
9.84 KM = 6.1 miles = MCS 15/13
12.69 KM = 7.9 miles = MCS 12/12
20.98 KM = 13 miles = MCS 12/12
