Gain ~ 4.5 + number of turns (3 turn minimum, 12 turn max) 
3 turns = 7 dbi 
4 turns = 8.5dbi 
5 turns = 9.5 dbi 
6 turns = 10.5 dbi 
7 turns = 11.25 dbi 
12 turns = 12.5 dbi