The Finco FM-5 is a dual-driven Yagi with ten elements on a 117″ boom. It was once manufactured by the Finney Company.
I modeled the antenna with the AO 9.67 Antenna Optimizer program. This image shows the antenna geometry.
This shows the segmentation of the driven elements and phasing line. Blue dots mark analysis segments. The red dot is the feedpoint.
Mike Bugaj used this FM-5 in the early 1970s at Anaheim, California. An instruction sheet is here.
Calculated performance is for 28 analysis segments per conductor halfwave. Forward gain includes mismatch and conductor losses. F/R is the ratio of forward power to that of the worst backlobe in the rear half-plane.
Frequency Impedance SWR Mismatch Conductor Forward F/R
MHz ohms Loss dB Loss dB Gain dBd dB
88 188+j60 1.70 0.30 0.02 7.14 21.58
89 183+j84 1.83 0.39 0.02 7.11 20.27
90 183+j104 1.93 0.46 0.01 7.13 19.10
91 187+j121 1.99 0.50 0.01 7.19 18.19
92 195+j135 2.00 0.51 0.01 7.29 17.43
93 207+j144 1.96 0.48 0.01 7.43 16.84
94 225+j147 1.87 0.42 0.02 7.62 16.37
95 246+j140 1.73 0.32 0.02 7.84 16.04
96 263+j118 1.55 0.21 0.02 8.08 15.80
97 269+j83 1.37 0.11 0.02 8.30 15.77
98 248+j38 1.27 0.06 0.02 8.46 15.98
99 212+j15 1.43 0.14 0.02 8.48 16.18
100 171+j13 1.76 0.34 0.02 8.36 16.47
101 138+j26 2.20 0.66 0.02 8.10 16.72
102 115+j47 2.70 1.03 0.02 7.77 16.86
103 102+j72 3.13 1.34 0.03 7.45 16.78
104 101+j96 3.32 1.48 0.03 7.27 16.50
105 114+j118 3.10 1.32 0.03 7.33 16.08
106 146+j119 2.46 0.85 0.03 7.62 15.91
107 160+j73 2.02 0.52 0.04 7.65 16.21
108 105+j40 2.92 1.19 0.05 6.52 17.44
Finco FM-5 Free Space 98 MHz 61 6063-T832 wires, inches rp = 0 de1p = 16 de2p = 33 d1p = 45 d2p = 57 d3p = 69 d4p = 81 d5p = 93 d6p = 105 d7p = 117 r = 35 de1 = 30 de2 = 23 d1 = 25.5 d2 = 25.5 d3 = 25.5 d4 = 24.5 d5 = 24.5 d6 = 23.5 d7 = 23.5 de1s = 10 de2s = 12 d = .375 ; Tubing diameter eqd = 1.35 ; Equivalent diameter of 0.5" sheath at bracket b = 2.3125 ; Bracket half-length w = .11 ; Phasing line diameter x1 = 27.5 xm = 29.5 x2 = 31.5 f = 21 1 rp -r 0 rp -b 0 d ; Reflector 1 rp -b 0 rp b 0 eqd 1 rp b 0 rp r 0 d 1 de1p -de1 -2 de1p -de1s -2 .375 ; Driven element 1 1 de1p -de1s -2 de1p -1 -2 .375 1 de1p 1 -2 de1p de1s -2 .375 1 de1p de1s -2 de1p de1 -2 .375 1 de1p -de1 0 de1p -de1s 0 .375 1 de1p -de1s 0 de1p -b 0 .375 1 de1p -b 0 de1p b 0 eqd 1 de1p b 0 de1p de1s 0 .375 1 de1p de1s 0 de1p de1 0 .375 1 de1p -de1 -2 de1p -de1 0 .375 1 de1p de1 -2 de1p de1 0 .375 1 de1p -de1s -2 de1p -de1s 0 .375 1 de1p de1s -2 de1p de1s 0 .375 1 de2p -de2 -2 de2p -de2s -2 .375 ; Driven element 2 1 de2p -de2s -2 de2p -1 -2 .375 1 de2p 1 -2 de2p de2s -2 .375 1 de2p de2s -2 de2p de2 -2 .375 1 de2p -de2 0 de2p -de2s 0 .375 1 de2p -de2s 0 de2p -b 0 .375 1 de2p -b 0 de2p b 0 eqd 1 de2p b 0 de2p de2s 0 .375 1 de2p de2s 0 de2p de2 0 .375 1 de2p -de2 -2 de2p -de2 0 .375 1 de2p de2 -2 de2p de2 0 .375 1 de2p -de2s -2 de2p -de2s 0 .375 1 de2p de2s -2 de2p de2s 0 .375 1 d1p -d1 0 d1p -b 0 d ; Directors 1 d1p -b 0 d1p b 0 eqd 1 d1p b 0 d1p d1 0 d 1 d2p -d2 0 d2p -b 0 d 1 d2p -b 0 d2p b 0 eqd 1 d2p b 0 d2p d2 0 d 1 d3p -d3 0 d3p -b 0 d 1 d3p -b 0 d3p b 0 eqd 1 d3p b 0 d3p d3 0 d 1 d4p -d4 0 d4p -b 0 d 1 d4p -b 0 d4p b 0 eqd 1 d4p b 0 d4p d4 0 d 1 d5p -d5 0 d5p -b 0 d 1 d5p -b 0 d5p b 0 eqd 1 d5p b 0 d5p d5 0 d 1 d6p -d6 0 d6p -b 0 d 1 d6p -b 0 d6p b 0 eqd 1 d6p b 0 d6p d6 0 d 1 d7p -d7 0 d7p -b 0 d 1 d7p -b 0 d7p b 0 eqd 1 d7p b 0 d7p d7 0 d 1 de1p -1 -2 f -1 -2 w ; Transmission line 1 f -1 -2 x1 -1 -2 w 1 x1 -1 -2 xm 0 -1.125 w 1 xm 0 -1.125 x2 1 -2 w 1 x2 1 -2 de2p 1 -2 w 1 de1p 1 -2 f 1 -2 w 1 f 1 -2 x1 1 -2 w 1 x1 1 -2 xm 0 -2.875 w 1 xm 0 -2.875 x2 -1 -2 w 1 x2 -1 -2 de2p -1 -2 w 2 f 1 -2 f -1 -2 w 1 source Wire 61, center This models the Finco FM-5 receiving antenna for the FM broadcast band. The elements use a 0.5"-diameter reinforcing sheath that I included in the mounting bracket model. It extends about 1.5" past the bracket, which I ignored.
88–108 MHz