110' loaded dipole:
Here are NEC simulation results for a 110', 1.85 MHz dipole placed 50' above
'average' Sommerfield-Norton GND. The VSWR bandwidth is for the stated input
impedance. For example, the centered loaded case with a 1:4 balun, or a 90
deg section of 25 ohm line, or with a hairpin inductor.
The loading coils are assigned a Q of 300, which is attainable with close
wound #14 AWG THHN (house wire) on a 10 cm diameter PVC form.
center loading 62 uH coils 63% efficiency Rin = 12
ohms 3:1 VSWR bandwidth 14 kHz
coils 25% from feedpoint 77 uH coils 66% efficiency Rin = 15
ohms 3:1 VSWR bandwidth 15 kHz
coils 50% from feedpoint 114 uH coils 66% efficiency Rin = 20
ohms 3:1 VSWR bandwidth 14 kHz
coils 75% from feedpoint 220 uH coils 69% efficiency Rin = 30
ohms 3:1 VSWR bandwidth 12 kHz
Dave WX7G
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