SL CFMI 4el Opt
Free Space Symmetric
101.100 MHz
10 6061-T6 wires, inches
rfs = -22		; 24.75
des = 0			; 0.00	
drs1 = 17.5		; 19.063
drs2 = 42.188		; 39.438
dia = .392
dia2 = .376		; 3/8" dia alum tubing
rfl = 30		; 31.813
dr1 = 26.25		; 23.188	
dr2 = 26		; 23.188

len = 27.75		; dr el half-length
sp = 1.824		; dr el upside dipole spacing	
nsp = -1.46		; dr el downside dipole spacing 

 1   0      -len   nsp   0       len   nsp    dia
 1   0      -len   sp    0       len    sp    dia
 1   0      -len   sp    0      -len   nsp    dia
 1   0       len   sp    0       len   nsp    dia

 1   rfs    -rfl   0    rfs     0.0    0    dia
 1   rfs     0.0   0    rfs     rfl    0    dia 
 1   drs1   -dr1   0    drs1    0.0    0    dia2
 1   drs1    0.0   0    drs1    dr1    0    dia2 
 1   drs2   -dr2   0    drs2    0.0    0    dia2
 1   drs2    0.0   0    drs2    dr2    0    dia2 
 1 source
 Wire 1, center

 This antenna was modeled from actual measurements of the Stellar Labs 4el
 FM antenna as modified by K6JRF for CFMI @ 101.1Mhz. AO analysis;
   9.33db F/G 
  12.32db F/B
  300 ohm feed impedance - 283 + j21 makes 
  SWR > 1.10:1.0

 In order to receive a mid-band FM station, it's is not quite what I would 
 like so it needs a bit of optimization. The elements lengths Ref, Dir 1 and
 Dir 2 s/b lengthened and spacings changed for reception @ 101.1Mhz 

 The antenna has a 300 to 75 stripline transformer built into the feed point
 making the transmission line (RG-6) a better way to send the signal to any
 FM tuner. Add three (3) ferrite line chokes (apx 1000 ohms) at the feed point 
 to further attenuate the common mode signal.