CM ============================================================ CM TRAPPED DIPOLE: 80M / 40M / 20M / 15M / 10M (5-BAND) CM Parallel resonant coaxial traps, horizontal, 15m AGL CM NEC-2 / EZNEC compatible CM CM Architecture (one side from feed outward): CM Feed CM -> [10M trap at 2.64m] CM -> [15M trap at 3.54m] CM -> [20M trap at 5.26m] CM -> [40M trap at 10.05m] CM -> tip at 20.1m CM CM Note: 15M uses loading effect of traps, not isolated element. CM Standard W3DZZ / commercial multiband trap dipole topology. CM CM Trap parameters (all RG-213): CM 10M trap: f0=28.5 MHz, L=0.50uH, C=63pF, Q=55, Rp=4863 ohm CM 15M trap: f0=21.225MHz, L=0.74uH, C=75pF, Q=63, Rp=6246 ohm CM 20M trap: f0=14.175MHz, L=1.23uH, C=103pF, Q=77, Rp=8452 ohm CM 40M trap: f0=7.150 MHz, L=2.87uH, C=173pF, Q=109,Rp=14024 ohm CM CM Wire layout (half dipole, feed at center, wires go in -X direction): CM W1: 0.00 to -2.64m (inner, 10M element) CM W2: -2.64 to -3.54m (10M to 15M trap) CM W3: -3.54 to -5.26m (15M to 20M trap) CM W4: -5.26 to -10.05m (20M to 40M trap) CM W5:-10.05 to -20.10m (40M to tip) CM Mirror for +X side: W6-W10 CM ============================================================ CE CM Tag Segs X1 Y1 Z1 X2 Y2 Z2 Radius GW 1 3 0.0 0.0 15.0 -2.64 0.0 15.0 0.00095 GW 2 1 -2.64 0.0 15.0 -3.54 0.0 15.0 0.00095 GW 3 2 -3.54 0.0 15.0 -5.26 0.0 15.0 0.00095 GW 4 5 -5.26 0.0 15.0 -10.05 0.0 15.0 0.00095 GW 5 10 -10.05 0.0 15.0 -20.10 0.0 15.0 0.00095 GW 6 3 2.64 0.0 15.0 0.0 0.0 15.0 0.00095 GW 7 1 3.54 0.0 15.0 2.64 0.0 15.0 0.00095 GW 8 2 5.26 0.0 15.0 3.54 0.0 15.0 0.00095 GW 9 5 10.05 0.0 15.0 5.26 0.0 15.0 0.00095 GW 10 10 20.10 0.0 15.0 10.05 0.0 15.0 0.00095 GE 1 GN 2 0 0 0 13.0 0.005 CM Feed: Wire 1, segment 2 (near center) EX 0 1 2 0 1.0 0.0 CM === TRAP LOADS === CM 10M traps — wires 1 and 6, far end segments CM Rs=1.61 ohm, L=0.50uH, C=63pF LD 0 1 3 3 1.61 5.0e-7 6.3e-11 LD 0 6 3 3 1.61 5.0e-7 6.3e-11 CM 15M traps — wires 2 and 7, far end CM Rs=1.57 ohm, L=0.74uH, C=75pF LD 0 2 1 1 1.57 7.4e-7 7.5e-11 LD 0 7 1 1 1.57 7.4e-7 7.5e-11 CM 20M traps — wires 3 and 8, far end CM Rs=1.43 ohm, L=1.23uH, C=103pF LD 0 3 2 2 1.43 1.23e-6 1.03e-10 LD 0 8 2 2 1.43 1.23e-6 1.03e-10 CM 40M traps — wires 4 and 9, far end CM Rs=1.24 ohm, L=2.87uH, C=173pF LD 0 4 5 5 1.24 2.87e-6 1.73e-10 LD 0 9 5 5 1.24 2.87e-6 1.73e-10 CM Frequency sweep — 40M band FR 0 13 0 0 7.0 0.025 CM Radiation pattern at 7.15 MHz RP 0 37 73 1000 0.0 0.0 5.0 5.0 EN CM ============================================================ CM FREQUENCY SWEEPS FOR EACH BAND (edit FR card): CM 10M: FR 0 17 0 0 28.0 0.1 CM 15M: FR 0 23 0 0 21.0 0.02 CM 20M: FR 0 15 0 0 14.0 0.025 CM 40M: FR 0 13 0 0 7.0 0.025 CM 80M: FR 0 11 0 0 3.5 0.025 CM CM EXPECTED PERFORMANCE vs UNTRAPPED REFERENCE: CM 10M: ~1-2 dBd loss due to trap losses (Q=55) CM 15M: ~1-2 dBd loss CM 20M: ~0.5-1 dBd loss (higher Q=77) CM 40M: ~0.3-0.8 dBd loss (Q=109 traps) CM 80M: ~0.5-1.5 dBd loss (accumulated trap losses) CM CM TYPICAL IMPEDANCES AT RESONANCE: CM 10M: ~50-75 ohm (good direct match) CM 20M: ~60-80 ohm (good match) CM 40M: ~55-70 ohm (good match) CM 80M: ~45-65 ohm (acceptable) CM 15M: ~50-80 ohm CM ============================================================