Antenna Gain Table

These are the manufacturer's provided gain tables to show gain or loss for various popular circular polarized antenna models used by LPFM and FM translator stations. 

Nicom BKG-77 & BKG-88

Bays Full Wave 0.85-spaced 0.5-spaced
1 -3 -3 -3
2 -0.05 2.14 -1.5
3 1.89 3.64 1.05
4 3.25 5.14 1.15
6 5.15 6.64 2.8
8 6.5 8.14 4.0

Nicom BKG1P

Bays Full Wave 0.85-spaced 0.5-spaced
1 2.14 2.14 2.14
2 5.1 4.75 4.1
3 4.91 6.64 4.58
4 8.1 8.01 6.7
6 9.5 9.64 8.9
8 10.9 10.5 9.6

Shively 6812b / c

Bays Full Wave 0.5-spaced
1 -3.39 -3.39
2 0.03 -1.51
3 1.92 0.08
4 3.21 1.19
5 4.20 2.10
6 4.99 2.84
8 6.26 4.04

SWR FMEC Plus

Bays Full Wave 0.75-spaced 0.5-spaced
1 -3.556 -3.556 -3.556
2 -0.182 -0.292 -1.580
3 1.746 1.449 0.052
4 3.105 2.660 1.183
5 4.133 3.619 2.103
6 4.997 4.403 2.842
8 6.346 5.640 4.026
10 7.389 6.818 4.954

ERI 100A

Bays Full Wave 0.5-spaced
1 -3.768 -3.768
2 -0.458 -2.007
4 2.833 0.704