W3DZZ Trap Dipole for 80 through 10 meters
Free Space
14.150 MHz
4 wires, feet
6  0 -54 0   0 -32 0  #12
6  0 -32 0   0   0 0  #12
6  0   0 0   0  32 0  #12
6  0  32 0   0  54 0  #12
1 source
12,100,0
2 loads
Laplace Transform
6,2
0 1
8.2 0
0 4.92E-4
18,2
0 1
8.2 0
0 4.92E-4

The ARRL Antenna Book says this antenna is resonant at 3750, 7200, 14150, and
29500, with a very broad resonance on 15 meters, and that the antenna shows a
SWR of less than 2 to 1 on 20, 15, and 10 using a 75 ohm feedline.  MN computes
the resonance points somewhat higher.  Try lengthening the inner and outer
wires to bring the resonant frequencies more into line.